From e4e2d6eba30bb743efe1665eefea46b152b94790 Mon Sep 17 00:00:00 2001
From: Rada Kamysheva <rada.kamysheva@databricks.com>
Date: Thu, 18 Jun 2026 17:30:50 +0000
Subject: [PATCH 1/9] acc: add Windows reproduction for export-dir on illegal
 notebook name

Reproduces databricks/cli#5171: `workspace export-dir` aborts on Windows
when a notebook name contains a ':' (e.g. an untitled "New Notebook
<timestamp>"), because the colon is illegal in a local Windows filename
and os.Create fails. The name is legal on Linux/macOS, so the test is
gated to Windows via GOOS.

output.txt is intentionally omitted: the golden cannot be generated on a
non-Windows machine, so the Windows CI leg will surface the real output
to commit verbatim.
---
 .../export-dir-illegal-filename/notebook.py   |  2 ++
 .../export-dir-illegal-filename/out.test.toml |  6 ++++
 .../export-dir-illegal-filename/script        |  7 +++++
 .../export-dir-illegal-filename/test.toml     | 28 +++++++++++++++++++
 4 files changed, 43 insertions(+)
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/notebook.py
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/out.test.toml
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/script
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/test.toml

diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/notebook.py b/acceptance/cmd/workspace/export-dir-illegal-filename/notebook.py
new file mode 100644
index 00000000000..4914a7436d9
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/notebook.py
@@ -0,0 +1,2 @@
+# Databricks notebook source
+print("hello")
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/out.test.toml b/acceptance/cmd/workspace/export-dir-illegal-filename/out.test.toml
new file mode 100644
index 00000000000..fee96cc336e
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/out.test.toml
@@ -0,0 +1,6 @@
+Local = true
+Cloud = false
+GOOS.darwin = false
+GOOS.linux = false
+GOOS.windows = true
+EnvMatrix.DATABRICKS_BUNDLE_ENGINE = ["terraform", "direct"]
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/script b/acceptance/cmd/workspace/export-dir-illegal-filename/script
new file mode 100644
index 00000000000..015d2e245c9
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/script
@@ -0,0 +1,7 @@
+$CLI workspace import "/test-dir/New Notebook 2026-05-04 13:54:24.py" --file notebook.py --format AUTO --language PYTHON
+
+mkdir -p "$TEST_TMP_DIR/export"
+
+# On Windows the notebook name contains ':' which is illegal in a local filename,
+# so os.Create fails and the whole export aborts (databricks/cli#5171).
+musterr trace $CLI workspace export-dir /test-dir "$TEST_TMP_DIR/export"
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/test.toml b/acceptance/cmd/workspace/export-dir-illegal-filename/test.toml
new file mode 100644
index 00000000000..c8c749d4f76
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/test.toml
@@ -0,0 +1,28 @@
+Local = true
+Cloud = false
+
+# This reproduces databricks/cli#5171, which only manifests on Windows: a ':' in
+# the notebook name is a legal filename character on Linux/macOS but illegal on
+# Windows, so os.Create rejects the local target path there.
+[GOOS]
+darwin = false
+linux = false
+windows = true
+
+[Env]
+MSYS_NO_PATHCONV = "1"
+
+[[Server]]
+Pattern = "GET /api/2.0/workspace/list"
+Response.Body = '''
+{
+  "objects": [
+    {
+      "path": "/test-dir/New Notebook 2026-05-04 13:54:24",
+      "object_type": "NOTEBOOK",
+      "language": "PYTHON",
+      "object_id": 123
+    }
+  ]
+}
+'''

From 193a0e752d42b0a7cb8001d4596035663ce88217 Mon Sep 17 00:00:00 2001
From: Rada Kamysheva <rada.kamysheva@databricks.com>
Date: Thu, 18 Jun 2026 19:16:24 +0000
Subject: [PATCH 2/9] acc: add captured Windows golden for export-dir illegal
 filename

Captured verbatim from the Windows CI run of the test added in the
previous commit. Documents the current (buggy) behavior of #5171:
export-dir aborts on Windows when a notebook name contains ':'.
---
 .../cmd/workspace/export-dir-illegal-filename/output.txt      | 4 ++++
 1 file changed, 4 insertions(+)
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/output.txt

diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt
new file mode 100644
index 00000000000..c4ef07323d3
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt
@@ -0,0 +1,4 @@
+
+>>> [CLI] workspace export-dir /test-dir [TEST_TMP_DIR]/export
+Exporting files from /test-dir
+Error: open [TEST_TMP_DIR]\export\New Notebook [TIMESTAMP].py: The filename, directory name, or volume label syntax is incorrect.

From 3a7aca246e387cedd5b14560f98b01bb94e9e3a5 Mon Sep 17 00:00:00 2001
From: Rada Kamysheva <rada.kamysheva@databricks.com>
Date: Thu, 18 Jun 2026 19:30:56 +0000
Subject: [PATCH 3/9] Skip workspace objects with names illegal as local files
 in export-dir

A workspace object name can be illegal as a local filename (e.g. the ':'
in an untitled "New Notebook 2026-05-04 13:54:24" on Windows), which made
os.Create fail and abort the entire export. Skip such files with a
warning and continue, matching the existing skip paths for non-exportable
and oversized objects.

Detection uses a build-tagged helper checking the Windows
ERROR_INVALID_NAME code; on other platforms no filename character (other
than '/' and NUL, which cannot appear in a workspace object name) is
illegal, so it is a no-op.

Flips the Windows-gated acceptance test from asserting the abort to
expecting skip-with-warning. Fixes #5171.
---
 NEXT_CHANGELOG.md                             |  1 +
 .../export-dir-illegal-filename/output.txt    |  3 ++-
 .../export-dir-illegal-filename/script        |  6 +++---
 cmd/workspace/workspace/export_dir.go         |  7 +++++++
 cmd/workspace/workspace/export_dir_other.go   | 11 ++++++++++
 cmd/workspace/workspace/export_dir_windows.go | 21 +++++++++++++++++++
 6 files changed, 45 insertions(+), 4 deletions(-)
 create mode 100644 cmd/workspace/workspace/export_dir_other.go
 create mode 100644 cmd/workspace/workspace/export_dir_windows.go

diff --git a/NEXT_CHANGELOG.md b/NEXT_CHANGELOG.md
index 1f46a0a57c6..6343eb4a1f4 100644
--- a/NEXT_CHANGELOG.md
+++ b/NEXT_CHANGELOG.md
@@ -5,6 +5,7 @@
 ### Notable Changes
 
 ### CLI
+* `workspace export-dir` no longer aborts when a workspace object's name is not a legal local filename (e.g. a notebook named `New Notebook 2026-05-04 13:54:24` whose `:` is illegal on Windows). Such files are now skipped with a warning and the export completes ([#5171](https://github.com/databricks/cli/issues/5171)).
 
 ### Bundles
 * `bundle run` now prints the modern job run URL (`/jobs/<id>/runs/<id>`) so that non-admin users permitted to view the run are taken to the run instead of the workspace homepage.
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt
index c4ef07323d3..c234e37825d 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt
@@ -1,4 +1,5 @@
 
 >>> [CLI] workspace export-dir /test-dir [TEST_TMP_DIR]/export
 Exporting files from /test-dir
-Error: open [TEST_TMP_DIR]\export\New Notebook [TIMESTAMP].py: The filename, directory name, or volume label syntax is incorrect.
+/test-dir/New Notebook [TIMESTAMP] (skipped; invalid name for local file system)
+Export complete
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/script b/acceptance/cmd/workspace/export-dir-illegal-filename/script
index 015d2e245c9..37b90688fd1 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/script
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/script
@@ -2,6 +2,6 @@ $CLI workspace import "/test-dir/New Notebook 2026-05-04 13:54:24.py" --file not
 
 mkdir -p "$TEST_TMP_DIR/export"
 
-# On Windows the notebook name contains ':' which is illegal in a local filename,
-# so os.Create fails and the whole export aborts (databricks/cli#5171).
-musterr trace $CLI workspace export-dir /test-dir "$TEST_TMP_DIR/export"
+# On Windows the notebook name contains ':' which is illegal in a local filename.
+# export-dir should skip it with a warning and still complete (databricks/cli#5171).
+trace $CLI workspace export-dir /test-dir "$TEST_TMP_DIR/export"
diff --git a/cmd/workspace/workspace/export_dir.go b/cmd/workspace/workspace/export_dir.go
index e7965bcda91..f06d7d16b2f 100644
--- a/cmd/workspace/workspace/export_dir.go
+++ b/cmd/workspace/workspace/export_dir.go
@@ -125,6 +125,13 @@ func (opts *exportDirOptions) callback(ctx context.Context, workspaceFiler filer
 		// create the file
 		f, err := os.Create(targetPath)
 		if err != nil {
+			// A workspace name can be illegal as a local filename (e.g. a ':'
+			// in "New Notebook 2026-05-04 13:54:24" on Windows). Skip those with
+			// a warning rather than aborting the whole export (#5171).
+			if isInvalidLocalNameError(err) {
+				cmdio.LogString(ctx, sourcePath+" (skipped; invalid name for local file system)")
+				return nil
+			}
 			return err
 		}
 		defer f.Close()
diff --git a/cmd/workspace/workspace/export_dir_other.go b/cmd/workspace/workspace/export_dir_other.go
new file mode 100644
index 00000000000..e2cd1741d17
--- /dev/null
+++ b/cmd/workspace/workspace/export_dir_other.go
@@ -0,0 +1,11 @@
+//go:build !windows
+
+package workspace
+
+// isInvalidLocalNameError reports whether err means the workspace object could
+// not be written because its name is not a legal filename on the local OS. On
+// non-Windows platforms the only bytes illegal in a filename are '/' and NUL,
+// neither of which can appear in a workspace object name, so this never fires.
+func isInvalidLocalNameError(err error) bool {
+	return false
+}
diff --git a/cmd/workspace/workspace/export_dir_windows.go b/cmd/workspace/workspace/export_dir_windows.go
new file mode 100644
index 00000000000..d1276ce2b3f
--- /dev/null
+++ b/cmd/workspace/workspace/export_dir_windows.go
@@ -0,0 +1,21 @@
+//go:build windows
+
+package workspace
+
+import (
+	"errors"
+	"syscall"
+)
+
+// errorInvalidName is the Windows ERROR_INVALID_NAME code. The file APIs return
+// it when a path contains characters that are illegal in a local filename, such
+// as the ':' in a notebook named "New Notebook 2026-05-04 13:54:24". It is not
+// declared in the standard syscall package, so we use the well-known code.
+// https://learn.microsoft.com/en-us/windows/win32/debug/system-error-codes--0-499-
+const errorInvalidName = syscall.Errno(0x7b)
+
+// isInvalidLocalNameError reports whether err means the workspace object could
+// not be written because its name is not a legal filename on the local OS.
+func isInvalidLocalNameError(err error) bool {
+	return errors.Is(err, errorInvalidName)
+}

From bba3ce77c0e3751a99f93ee0ed6f6564c8fe9096 Mon Sep 17 00:00:00 2001
From: Rada Kamysheva <rada.kamysheva@databricks.com>
Date: Thu, 18 Jun 2026 19:37:26 +0000
Subject: [PATCH 4/9] Add boundary unit test for isInvalidLocalNameError

Locks in the narrow contract that only the Windows ERROR_INVALID_NAME
error is treated as skippable, while permission, not-exist, generic, and
nil errors are not. The acceptance test only exercises the positive
(invalid-name) path, so this guards against accidentally broadening the
check and silently dropping files on real I/O failures.
---
 .../workspace/export_dir_windows_test.go      | 56 +++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 cmd/workspace/workspace/export_dir_windows_test.go

diff --git a/cmd/workspace/workspace/export_dir_windows_test.go b/cmd/workspace/workspace/export_dir_windows_test.go
new file mode 100644
index 00000000000..aba1e735aa4
--- /dev/null
+++ b/cmd/workspace/workspace/export_dir_windows_test.go
@@ -0,0 +1,56 @@
+//go:build windows
+
+package workspace
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+	"syscall"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// The narrow contract: only the Windows "invalid file name" error is treated as
+// skippable. Genuine failures (permission, missing path, anything else) must not
+// be swallowed, otherwise export-dir would silently drop files on real errors.
+func TestIsInvalidLocalNameError(t *testing.T) {
+	tests := []struct {
+		name string
+		err  error
+		want bool
+	}{
+		{
+			name: "invalid name wrapped in PathError",
+			err:  &os.PathError{Op: "open", Path: `C:\tmp\New Notebook 13:54:24.py`, Err: syscall.Errno(0x7b)},
+			want: true,
+		},
+		{
+			name: "permission denied is not skipped",
+			err:  fs.ErrPermission,
+			want: false,
+		},
+		{
+			name: "not exist is not skipped",
+			err:  fs.ErrNotExist,
+			want: false,
+		},
+		{
+			name: "generic error is not skipped",
+			err:  errors.New("boom"),
+			want: false,
+		},
+		{
+			name: "nil is not skipped",
+			err:  nil,
+			want: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, isInvalidLocalNameError(tt.err))
+		})
+	}
+}

From 50a000c6831f566833c7812c3e0cf698f1be29f1 Mon Sep 17 00:00:00 2001
From: Rada Kamysheva <rada.kamysheva@databricks.com>
Date: Fri, 19 Jun 2026 12:55:31 +0000
Subject: [PATCH 5/9] acc: run export-dir illegal-filename test on all OSes

The test reproducing databricks/cli#5171 was gated to Windows only because a
':' in the notebook name is illegal as a local filename on Windows but legal on
Linux/macOS, so export-dir skips it there and exports it everywhere else.

Run it on every OS and capture the divergent output in out.<goos>.txt. Teach the
acceptance runner to compare only the current OS's out.<goos>.txt and skip the
others (extending the existing variant-skip machinery), since otherwise the
non-current goldens would fail as "Missing output file".

Add a fake WorkspaceList handler so the imported notebook is listed and actually
exported, replacing the hardcoded [[Server]] list stub.
---
 acceptance/acceptance_test.go                 | 32 +++++++++++++++----
 .../out.darwin.txt                            |  5 +++
 .../export-dir-illegal-filename/out.linux.txt |  5 +++
 .../export-dir-illegal-filename/out.test.toml |  3 --
 .../out.windows.txt                           |  5 +++
 .../export-dir-illegal-filename/output.txt    |  5 +--
 .../export-dir-illegal-filename/script        | 15 +++++++--
 .../export-dir-illegal-filename/test.toml     | 31 ++++++------------
 libs/testserver/fake_workspace.go             | 26 +++++++++++++++
 libs/testserver/handlers.go                   |  5 +++
 10 files changed, 93 insertions(+), 39 deletions(-)
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/out.darwin.txt
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/out.linux.txt
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/out.windows.txt

diff --git a/acceptance/acceptance_test.go b/acceptance/acceptance_test.go
index 2d3326b23d6..09bd0fd973a 100644
--- a/acceptance/acceptance_test.go
+++ b/acceptance/acceptance_test.go
@@ -1633,18 +1633,38 @@ type pathFilter struct {
 	// contains substrings from the variants other than current.
 	// E.g. if EnvVaryOutput is DATABRICKS_BUNDLE_ENGINE and current test running DATABRICKS_BUNDLE_ENGINE="terraform" then
 	// notSelected contains ".direct." meaning if filename contains that (e.g. out.deploy.direct.txt) then we ignore it here.
+	// It also contains the infixes of every GOOS other than runtime.GOOS, so out.<goos>.txt files for other OSes are ignored.
 	notSelected []string
 }
 
-// preparePathFilter builds filter based on EnvVaryOutput and current variant env.
+// osVariants are the GOOS values that can tag an output file (e.g.
+// out.windows.txt). Files tagged with an OS other than runtime.GOOS are skipped
+// during comparison, so a single test can capture per-OS output differences
+// (see cmd/workspace/export-dir-illegal-filename, databricks/cli#5171).
+var osVariants = []string{"darwin", "linux", "windows"}
+
+// preparePathFilter builds filter based on the current GOOS and EnvVaryOutput.
 func preparePathFilter(config internal.TestConfig, customEnv []string) pathFilter {
+	var notSelected []string
+	for _, goos := range osVariants {
+		if goos != runtime.GOOS {
+			notSelected = append(notSelected, "."+goos+".")
+		}
+	}
+	notSelected = append(notSelected, envVaryNotSelected(config, customEnv)...)
+	return pathFilter{notSelected: notSelected}
+}
+
+// envVaryNotSelected returns the infixes of EnvVaryOutput variants other than
+// the one selected for the current test run.
+func envVaryNotSelected(config internal.TestConfig, customEnv []string) []string {
 	if config.EnvVaryOutput == nil {
-		return pathFilter{}
+		return nil
 	}
 	key := *config.EnvVaryOutput
 	vals := config.EnvMatrix[key]
 	if len(vals) <= 1 {
-		return pathFilter{}
+		return nil
 	}
 	selected := ""
 	for _, kv := range customEnv {
@@ -1655,7 +1675,7 @@ func preparePathFilter(config internal.TestConfig, customEnv []string) pathFilte
 		}
 	}
 	if selected == "" {
-		return pathFilter{}
+		return nil
 	}
 	var others []string
 	for _, v := range vals {
@@ -1664,9 +1684,7 @@ func preparePathFilter(config internal.TestConfig, customEnv []string) pathFilte
 		}
 		others = append(others, "."+v+".")
 	}
-	return pathFilter{
-		notSelected: others,
-	}
+	return others
 }
 
 // shouldSkip returns true if the given file belongs to a non-selected variant.
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/out.darwin.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/out.darwin.txt
new file mode 100644
index 00000000000..846fd8cab36
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/out.darwin.txt
@@ -0,0 +1,5 @@
+
+>>> [CLI] workspace export-dir /test-dir [TEST_TMP_DIR]/export
+Exporting files from /test-dir
+/test-dir/New Notebook [TIMESTAMP] -> [TEST_TMP_DIR]/export/New Notebook [TIMESTAMP].py
+Export complete
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/out.linux.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/out.linux.txt
new file mode 100644
index 00000000000..846fd8cab36
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/out.linux.txt
@@ -0,0 +1,5 @@
+
+>>> [CLI] workspace export-dir /test-dir [TEST_TMP_DIR]/export
+Exporting files from /test-dir
+/test-dir/New Notebook [TIMESTAMP] -> [TEST_TMP_DIR]/export/New Notebook [TIMESTAMP].py
+Export complete
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/out.test.toml b/acceptance/cmd/workspace/export-dir-illegal-filename/out.test.toml
index fee96cc336e..f784a183258 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/out.test.toml
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/out.test.toml
@@ -1,6 +1,3 @@
 Local = true
 Cloud = false
-GOOS.darwin = false
-GOOS.linux = false
-GOOS.windows = true
 EnvMatrix.DATABRICKS_BUNDLE_ENGINE = ["terraform", "direct"]
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/out.windows.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/out.windows.txt
new file mode 100644
index 00000000000..c234e37825d
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/out.windows.txt
@@ -0,0 +1,5 @@
+
+>>> [CLI] workspace export-dir /test-dir [TEST_TMP_DIR]/export
+Exporting files from /test-dir
+/test-dir/New Notebook [TIMESTAMP] (skipped; invalid name for local file system)
+Export complete
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt
index c234e37825d..3ba158aa4b1 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt
@@ -1,5 +1,2 @@
 
->>> [CLI] workspace export-dir /test-dir [TEST_TMP_DIR]/export
-Exporting files from /test-dir
-/test-dir/New Notebook [TIMESTAMP] (skipped; invalid name for local file system)
-Export complete
+=== export-dir output is OS-specific; see out.<goos>.txt
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/script b/acceptance/cmd/workspace/export-dir-illegal-filename/script
index 37b90688fd1..9b5070885a2 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/script
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/script
@@ -2,6 +2,15 @@ $CLI workspace import "/test-dir/New Notebook 2026-05-04 13:54:24.py" --file not
 
 mkdir -p "$TEST_TMP_DIR/export"
 
-# On Windows the notebook name contains ':' which is illegal in a local filename.
-# export-dir should skip it with a warning and still complete (databricks/cli#5171).
-trace $CLI workspace export-dir /test-dir "$TEST_TMP_DIR/export"
+# The notebook name contains ':', which is illegal in a local filename on Windows
+# but legal on Linux/macOS. export-dir skips it with a warning on Windows and
+# exports it normally elsewhere (databricks/cli#5171). The output therefore
+# differs per OS, so capture it in out.<goos>.txt.
+case "$OSTYPE" in
+    msys | cygwin | win32) goos=windows ;;
+    darwin*) goos=darwin ;;
+    *) goos=linux ;;
+esac
+
+title "export-dir output is OS-specific; see out.<goos>.txt\n"
+trace $CLI workspace export-dir /test-dir "$TEST_TMP_DIR/export" >"out.$goos.txt" 2>&1
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/test.toml b/acceptance/cmd/workspace/export-dir-illegal-filename/test.toml
index c8c749d4f76..3dfbea904a5 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/test.toml
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/test.toml
@@ -1,28 +1,15 @@
 Local = true
 Cloud = false
 
-# This reproduces databricks/cli#5171, which only manifests on Windows: a ':' in
-# the notebook name is a legal filename character on Linux/macOS but illegal on
-# Windows, so os.Create rejects the local target path there.
-[GOOS]
-darwin = false
-linux = false
-windows = true
+# This reproduces databricks/cli#5171. The notebook name contains a ':', which is
+# a legal filename character on Linux/macOS but illegal on Windows. The export is
+# therefore skipped with a warning on Windows and succeeds elsewhere, so the test
+# runs on every OS and captures the divergent output in out.<goos>.txt.
+
+# output.txt only holds an OS-independent header; the captured output lives in
+# out.<goos>.txt. The exported notebook lands under the temp dir on Linux/macOS;
+# it is not part of the comparison, only the captured output is.
+Ignore = ["export/"]
 
 [Env]
 MSYS_NO_PATHCONV = "1"
-
-[[Server]]
-Pattern = "GET /api/2.0/workspace/list"
-Response.Body = '''
-{
-  "objects": [
-    {
-      "path": "/test-dir/New Notebook 2026-05-04 13:54:24",
-      "object_type": "NOTEBOOK",
-      "language": "PYTHON",
-      "object_id": 123
-    }
-  ]
-}
-'''
diff --git a/libs/testserver/fake_workspace.go b/libs/testserver/fake_workspace.go
index d2925fb1e38..9b7a6fcc91c 100644
--- a/libs/testserver/fake_workspace.go
+++ b/libs/testserver/fake_workspace.go
@@ -8,6 +8,7 @@ import (
 	"os"
 	"path"
 	"path/filepath"
+	"slices"
 	"strings"
 	"sync"
 	"time"
@@ -370,6 +371,31 @@ func (s *FakeWorkspace) WorkspaceGetStatus(path string) Response {
 	}
 }
 
+func (s *FakeWorkspace) WorkspaceList(listPath string) Response {
+	defer s.LockUnlock()()
+
+	var objects []workspace.ObjectInfo
+
+	for filePath, entry := range s.files {
+		if path.Dir(filePath) == listPath {
+			objects = append(objects, entry.Info)
+		}
+	}
+	for dirPath, dirInfo := range s.directories {
+		if dirPath != listPath && path.Dir(dirPath) == listPath {
+			objects = append(objects, dirInfo)
+		}
+	}
+
+	slices.SortFunc(objects, func(a, b workspace.ObjectInfo) int {
+		return strings.Compare(a.Path, b.Path)
+	})
+
+	return Response{
+		Body: workspace.ListResponse{Objects: objects},
+	}
+}
+
 func (s *FakeWorkspace) WorkspaceMkdirs(request workspace.Mkdirs) {
 	defer s.LockUnlock()()
 	s.directories[request.Path] = workspace.ObjectInfo{
diff --git a/libs/testserver/handlers.go b/libs/testserver/handlers.go
index 8f611a7c7c9..0756af5d0ff 100644
--- a/libs/testserver/handlers.go
+++ b/libs/testserver/handlers.go
@@ -79,6 +79,11 @@ func AddDefaultHandlers(server *Server) {
 		return req.Workspace.WorkspaceGetStatus(path)
 	})
 
+	server.Handle("GET", "/api/2.0/workspace/list", func(req Request) any {
+		path := req.URL.Query().Get("path")
+		return req.Workspace.WorkspaceList(path)
+	})
+
 	server.Handle("POST", "/api/2.0/workspace/mkdirs", func(req Request) any {
 		var request workspace.Mkdirs
 		if err := json.Unmarshal(req.Body, &request); err != nil {

From ffbf66e314ea695098677b3572185f76c21b294f Mon Sep 17 00:00:00 2001
From: Rada Kamysheva <rada.kamysheva@databricks.com>
Date: Mon, 22 Jun 2026 06:14:22 +0000
Subject: [PATCH 6/9] acc: split export-dir illegal-filename test by OS instead
 of in-runner GOOS filtering

Revert the per-GOOS output filtering added to the acceptance runner
(osVariants / preparePathFilter) and instead express the OS-specific behaviour
with two GOOS-gated leaf tests that share a single _script and notebook fixture:

  export-dir-illegal-filename/
    _script        # import + export-dir, shared by both leaves
    notebook.py    # shared fixture, referenced via $TESTDIR/../notebook.py
    posix/         # GOOS.windows = false  -> notebook exported
    windows/       # GOOS.{linux,darwin} = false -> skipped with a warning

The ':' in the notebook name is legal on Linux/macOS but illegal as a local
Windows filename, so export-dir skips it on Windows (databricks/cli#5171). The
two captured outputs differ, but everything else is shared, so the leaves only
carry their GOOS gate and golden. This keeps OS knowledge out of the shared
acceptance runner.
---
 acceptance/acceptance_test.go                 | 32 ++++---------------
 .../export-dir-illegal-filename/_script       |  9 ++++++
 .../export-dir-illegal-filename/out.linux.txt |  5 ---
 .../export-dir-illegal-filename/output.txt    |  2 --
 .../{ => posix}/out.test.toml                 |  1 +
 .../{out.darwin.txt => posix/output.txt}      |  0
 .../export-dir-illegal-filename/posix/script  |  1 +
 .../posix/test.toml                           |  3 ++
 .../export-dir-illegal-filename/script        | 16 ----------
 .../export-dir-illegal-filename/test.toml     | 13 ++++----
 .../windows/out.test.toml                     |  5 +++
 .../{out.windows.txt => windows/output.txt}   |  0
 .../windows/script                            |  1 +
 .../windows/test.toml                         |  4 +++
 14 files changed, 37 insertions(+), 55 deletions(-)
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/_script
 delete mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/out.linux.txt
 delete mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/output.txt
 rename acceptance/cmd/workspace/export-dir-illegal-filename/{ => posix}/out.test.toml (80%)
 rename acceptance/cmd/workspace/export-dir-illegal-filename/{out.darwin.txt => posix/output.txt} (100%)
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/posix/script
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/posix/test.toml
 delete mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/script
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/windows/out.test.toml
 rename acceptance/cmd/workspace/export-dir-illegal-filename/{out.windows.txt => windows/output.txt} (100%)
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/windows/script
 create mode 100644 acceptance/cmd/workspace/export-dir-illegal-filename/windows/test.toml

diff --git a/acceptance/acceptance_test.go b/acceptance/acceptance_test.go
index 09bd0fd973a..2d3326b23d6 100644
--- a/acceptance/acceptance_test.go
+++ b/acceptance/acceptance_test.go
@@ -1633,38 +1633,18 @@ type pathFilter struct {
 	// contains substrings from the variants other than current.
 	// E.g. if EnvVaryOutput is DATABRICKS_BUNDLE_ENGINE and current test running DATABRICKS_BUNDLE_ENGINE="terraform" then
 	// notSelected contains ".direct." meaning if filename contains that (e.g. out.deploy.direct.txt) then we ignore it here.
-	// It also contains the infixes of every GOOS other than runtime.GOOS, so out.<goos>.txt files for other OSes are ignored.
 	notSelected []string
 }
 
-// osVariants are the GOOS values that can tag an output file (e.g.
-// out.windows.txt). Files tagged with an OS other than runtime.GOOS are skipped
-// during comparison, so a single test can capture per-OS output differences
-// (see cmd/workspace/export-dir-illegal-filename, databricks/cli#5171).
-var osVariants = []string{"darwin", "linux", "windows"}
-
-// preparePathFilter builds filter based on the current GOOS and EnvVaryOutput.
+// preparePathFilter builds filter based on EnvVaryOutput and current variant env.
 func preparePathFilter(config internal.TestConfig, customEnv []string) pathFilter {
-	var notSelected []string
-	for _, goos := range osVariants {
-		if goos != runtime.GOOS {
-			notSelected = append(notSelected, "."+goos+".")
-		}
-	}
-	notSelected = append(notSelected, envVaryNotSelected(config, customEnv)...)
-	return pathFilter{notSelected: notSelected}
-}
-
-// envVaryNotSelected returns the infixes of EnvVaryOutput variants other than
-// the one selected for the current test run.
-func envVaryNotSelected(config internal.TestConfig, customEnv []string) []string {
 	if config.EnvVaryOutput == nil {
-		return nil
+		return pathFilter{}
 	}
 	key := *config.EnvVaryOutput
 	vals := config.EnvMatrix[key]
 	if len(vals) <= 1 {
-		return nil
+		return pathFilter{}
 	}
 	selected := ""
 	for _, kv := range customEnv {
@@ -1675,7 +1655,7 @@ func envVaryNotSelected(config internal.TestConfig, customEnv []string) []string
 		}
 	}
 	if selected == "" {
-		return nil
+		return pathFilter{}
 	}
 	var others []string
 	for _, v := range vals {
@@ -1684,7 +1664,9 @@ func envVaryNotSelected(config internal.TestConfig, customEnv []string) []string
 		}
 		others = append(others, "."+v+".")
 	}
-	return others
+	return pathFilter{
+		notSelected: others,
+	}
 }
 
 // shouldSkip returns true if the given file belongs to a non-selected variant.
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/_script b/acceptance/cmd/workspace/export-dir-illegal-filename/_script
new file mode 100644
index 00000000000..02aa74de7e0
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/_script
@@ -0,0 +1,9 @@
+# Shared by the posix/ and windows/ leaf tests, which differ only in their GOOS
+# gate and golden output. The notebook name contains ':', which is a legal local
+# filename character on Linux/macOS but illegal on Windows, so export-dir skips it
+# with a warning on Windows and exports it normally elsewhere (databricks/cli#5171).
+$CLI workspace import "/test-dir/New Notebook 2026-05-04 13:54:24.py" --file "$TESTDIR/../notebook.py" --format AUTO --language PYTHON
+
+mkdir -p "$TEST_TMP_DIR/export"
+
+trace $CLI workspace export-dir /test-dir "$TEST_TMP_DIR/export"
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/out.linux.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/out.linux.txt
deleted file mode 100644
index 846fd8cab36..00000000000
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/out.linux.txt
+++ /dev/null
@@ -1,5 +0,0 @@
-
->>> [CLI] workspace export-dir /test-dir [TEST_TMP_DIR]/export
-Exporting files from /test-dir
-/test-dir/New Notebook [TIMESTAMP] -> [TEST_TMP_DIR]/export/New Notebook [TIMESTAMP].py
-Export complete
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt
deleted file mode 100644
index 3ba158aa4b1..00000000000
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/output.txt
+++ /dev/null
@@ -1,2 +0,0 @@
-
-=== export-dir output is OS-specific; see out.<goos>.txt
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/out.test.toml b/acceptance/cmd/workspace/export-dir-illegal-filename/posix/out.test.toml
similarity index 80%
rename from acceptance/cmd/workspace/export-dir-illegal-filename/out.test.toml
rename to acceptance/cmd/workspace/export-dir-illegal-filename/posix/out.test.toml
index f784a183258..1baaa898c5b 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/out.test.toml
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/posix/out.test.toml
@@ -1,3 +1,4 @@
 Local = true
 Cloud = false
+GOOS.windows = false
 EnvMatrix.DATABRICKS_BUNDLE_ENGINE = ["terraform", "direct"]
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/out.darwin.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/posix/output.txt
similarity index 100%
rename from acceptance/cmd/workspace/export-dir-illegal-filename/out.darwin.txt
rename to acceptance/cmd/workspace/export-dir-illegal-filename/posix/output.txt
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/posix/script b/acceptance/cmd/workspace/export-dir-illegal-filename/posix/script
new file mode 100644
index 00000000000..6125f11b143
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/posix/script
@@ -0,0 +1 @@
+source "$TESTDIR/../_script"
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/posix/test.toml b/acceptance/cmd/workspace/export-dir-illegal-filename/posix/test.toml
new file mode 100644
index 00000000000..96be3f28dce
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/posix/test.toml
@@ -0,0 +1,3 @@
+# The ':' in the notebook name is a legal local filename on Linux/macOS, so the
+# notebook is exported. Windows diverges and is covered by ../windows.
+GOOS.windows = false
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/script b/acceptance/cmd/workspace/export-dir-illegal-filename/script
deleted file mode 100644
index 9b5070885a2..00000000000
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/script
+++ /dev/null
@@ -1,16 +0,0 @@
-$CLI workspace import "/test-dir/New Notebook 2026-05-04 13:54:24.py" --file notebook.py --format AUTO --language PYTHON
-
-mkdir -p "$TEST_TMP_DIR/export"
-
-# The notebook name contains ':', which is illegal in a local filename on Windows
-# but legal on Linux/macOS. export-dir skips it with a warning on Windows and
-# exports it normally elsewhere (databricks/cli#5171). The output therefore
-# differs per OS, so capture it in out.<goos>.txt.
-case "$OSTYPE" in
-    msys | cygwin | win32) goos=windows ;;
-    darwin*) goos=darwin ;;
-    *) goos=linux ;;
-esac
-
-title "export-dir output is OS-specific; see out.<goos>.txt\n"
-trace $CLI workspace export-dir /test-dir "$TEST_TMP_DIR/export" >"out.$goos.txt" 2>&1
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/test.toml b/acceptance/cmd/workspace/export-dir-illegal-filename/test.toml
index 3dfbea904a5..20b44bad782 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/test.toml
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/test.toml
@@ -1,14 +1,13 @@
 Local = true
 Cloud = false
 
-# This reproduces databricks/cli#5171. The notebook name contains a ':', which is
-# a legal filename character on Linux/macOS but illegal on Windows. The export is
-# therefore skipped with a warning on Windows and succeeds elsewhere, so the test
-# runs on every OS and captures the divergent output in out.<goos>.txt.
+# This reproduces databricks/cli#5171. The behaviour is OS-specific (see _script),
+# so the actual test cases live in the posix/ and windows/ leaf directories, each
+# GOOS-gated with its own golden. This directory only holds the shared _script,
+# the notebook fixture, and the config they inherit.
 
-# output.txt only holds an OS-independent header; the captured output lives in
-# out.<goos>.txt. The exported notebook lands under the temp dir on Linux/macOS;
-# it is not part of the comparison, only the captured output is.
+# The exported notebook lands under $TEST_TMP_DIR/export and is not part of the
+# comparison; only the captured command output is.
 Ignore = ["export/"]
 
 [Env]
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/windows/out.test.toml b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/out.test.toml
new file mode 100644
index 00000000000..8471d88c7f3
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/out.test.toml
@@ -0,0 +1,5 @@
+Local = true
+Cloud = false
+GOOS.darwin = false
+GOOS.linux = false
+EnvMatrix.DATABRICKS_BUNDLE_ENGINE = ["terraform", "direct"]
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/out.windows.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt
similarity index 100%
rename from acceptance/cmd/workspace/export-dir-illegal-filename/out.windows.txt
rename to acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/windows/script b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/script
new file mode 100644
index 00000000000..6125f11b143
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/script
@@ -0,0 +1 @@
+source "$TESTDIR/../_script"
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/windows/test.toml b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/test.toml
new file mode 100644
index 00000000000..ba1520ad133
--- /dev/null
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/test.toml
@@ -0,0 +1,4 @@
+# The ':' in the notebook name is illegal as a local Windows filename, so
+# export-dir skips it with a warning. Linux/macOS are covered by ../posix.
+GOOS.linux = false
+GOOS.darwin = false

From 47a2aa8a5681cfc9ffcefad106b45735f6388166 Mon Sep 17 00:00:00 2001
From: Rada Kamysheva <rada.kamysheva@databricks.com>
Date: Mon, 22 Jun 2026 13:39:44 +0000
Subject: [PATCH 7/9] Rename workspace objects with locally-illegal names in
 export-dir instead of skipping

Previously export-dir skipped workspace objects whose names are not legal
local filenames (e.g. the ':' in "New Notebook 2026-05-04 13:54:24" on
Windows). Skipping silently dropped the file. Now the object is exported
under a sanitized name (illegal characters replaced with '_') and a
warning is emitted, so the content is preserved.

Adds a build-tagged sanitizeLocalName helper (Windows replaces the
reserved set plus control characters; no-op elsewhere) and a unit test
covering it. Flips the Windows-gated acceptance golden from skip to
rename-with-warning. Relates to #5171.
---
 NEXT_CHANGELOG.md                             |  2 +-
 .../export-dir-illegal-filename/_script       |  5 +--
 .../windows/output.txt                        |  3 +-
 .../windows/test.toml                         |  3 +-
 cmd/workspace/workspace/export_dir.go         | 17 +++++----
 cmd/workspace/workspace/export_dir_other.go   |  7 ++++
 cmd/workspace/workspace/export_dir_windows.go | 17 +++++++++
 .../workspace/export_dir_windows_test.go      | 35 +++++++++++++++++++
 8 files changed, 78 insertions(+), 11 deletions(-)

diff --git a/NEXT_CHANGELOG.md b/NEXT_CHANGELOG.md
index 6343eb4a1f4..4ad8ebccffd 100644
--- a/NEXT_CHANGELOG.md
+++ b/NEXT_CHANGELOG.md
@@ -5,7 +5,7 @@
 ### Notable Changes
 
 ### CLI
-* `workspace export-dir` no longer aborts when a workspace object's name is not a legal local filename (e.g. a notebook named `New Notebook 2026-05-04 13:54:24` whose `:` is illegal on Windows). Such files are now skipped with a warning and the export completes ([#5171](https://github.com/databricks/cli/issues/5171)).
+* `workspace export-dir` no longer aborts when a workspace object's name is not a legal local filename (e.g. a notebook named `New Notebook 2026-05-04 13:54:24` whose `:` is illegal on Windows). Such files are now exported under a sanitized name with a warning and the export completes ([#5171](https://github.com/databricks/cli/issues/5171)).
 
 ### Bundles
 * `bundle run` now prints the modern job run URL (`/jobs/<id>/runs/<id>`) so that non-admin users permitted to view the run are taken to the run instead of the workspace homepage.
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/_script b/acceptance/cmd/workspace/export-dir-illegal-filename/_script
index 02aa74de7e0..50af95c6962 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/_script
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/_script
@@ -1,7 +1,8 @@
 # Shared by the posix/ and windows/ leaf tests, which differ only in their GOOS
 # gate and golden output. The notebook name contains ':', which is a legal local
-# filename character on Linux/macOS but illegal on Windows, so export-dir skips it
-# with a warning on Windows and exports it normally elsewhere (databricks/cli#5171).
+# filename character on Linux/macOS but illegal on Windows, so export-dir renames
+# it to a legal name with a warning on Windows and exports it normally elsewhere
+# (databricks/cli#5171).
 $CLI workspace import "/test-dir/New Notebook 2026-05-04 13:54:24.py" --file "$TESTDIR/../notebook.py" --format AUTO --language PYTHON
 
 mkdir -p "$TEST_TMP_DIR/export"
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt
index c234e37825d..7cde3c92f51 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt
@@ -1,5 +1,6 @@
 
 >>> [CLI] workspace export-dir /test-dir [TEST_TMP_DIR]/export
 Exporting files from /test-dir
-/test-dir/New Notebook [TIMESTAMP] (skipped; invalid name for local file system)
+Warn: /test-dir/New Notebook [TIMESTAMP]: name is not valid for the local file system, exporting as "New Notebook 2026-05-04 13_54_24.py"
+/test-dir/New Notebook [TIMESTAMP] -> [TEST_TMP_DIR]\export\New Notebook 2026-05-04 13_54_24.py
 Export complete
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/windows/test.toml b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/test.toml
index ba1520ad133..9893864def7 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/windows/test.toml
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/test.toml
@@ -1,4 +1,5 @@
 # The ':' in the notebook name is illegal as a local Windows filename, so
-# export-dir skips it with a warning. Linux/macOS are covered by ../posix.
+# export-dir renames it to a legal name with a warning. Linux/macOS are covered
+# by ../posix.
 GOOS.linux = false
 GOOS.darwin = false
diff --git a/cmd/workspace/workspace/export_dir.go b/cmd/workspace/workspace/export_dir.go
index f06d7d16b2f..77056f4d28c 100644
--- a/cmd/workspace/workspace/export_dir.go
+++ b/cmd/workspace/workspace/export_dir.go
@@ -16,6 +16,7 @@ import (
 	"github.com/databricks/cli/libs/cmdctx"
 	"github.com/databricks/cli/libs/cmdio"
 	"github.com/databricks/cli/libs/filer"
+	"github.com/databricks/cli/libs/log"
 	"github.com/databricks/cli/libs/notebook"
 	"github.com/databricks/databricks-sdk-go/apierr"
 	"github.com/databricks/databricks-sdk-go/service/workspace"
@@ -126,13 +127,17 @@ func (opts *exportDirOptions) callback(ctx context.Context, workspaceFiler filer
 		f, err := os.Create(targetPath)
 		if err != nil {
 			// A workspace name can be illegal as a local filename (e.g. a ':'
-			// in "New Notebook 2026-05-04 13:54:24" on Windows). Skip those with
-			// a warning rather than aborting the whole export (#5171).
-			if isInvalidLocalNameError(err) {
-				cmdio.LogString(ctx, sourcePath+" (skipped; invalid name for local file system)")
-				return nil
+			// in "New Notebook 2026-05-04 13:54:24" on Windows). Rename it to a
+			// legal name with a warning rather than aborting the export (#5171).
+			if !isInvalidLocalNameError(err) {
+				return err
+			}
+			targetPath = filepath.Join(filepath.Dir(targetPath), sanitizeLocalName(filepath.Base(targetPath)))
+			log.Warnf(ctx, "%s: name is not valid for the local file system, exporting as %q", sourcePath, filepath.Base(targetPath))
+			f, err = os.Create(targetPath)
+			if err != nil {
+				return err
 			}
-			return err
 		}
 		defer f.Close()
 
diff --git a/cmd/workspace/workspace/export_dir_other.go b/cmd/workspace/workspace/export_dir_other.go
index e2cd1741d17..3ada8e8d3eb 100644
--- a/cmd/workspace/workspace/export_dir_other.go
+++ b/cmd/workspace/workspace/export_dir_other.go
@@ -9,3 +9,10 @@ package workspace
 func isInvalidLocalNameError(err error) bool {
 	return false
 }
+
+// sanitizeLocalName is a no-op on non-Windows platforms. It exists to satisfy
+// the call in export_dir.go, which is only reached when isInvalidLocalNameError
+// returns true, so this is never invoked here.
+func sanitizeLocalName(name string) string {
+	return name
+}
diff --git a/cmd/workspace/workspace/export_dir_windows.go b/cmd/workspace/workspace/export_dir_windows.go
index d1276ce2b3f..40881e0d4e1 100644
--- a/cmd/workspace/workspace/export_dir_windows.go
+++ b/cmd/workspace/workspace/export_dir_windows.go
@@ -4,6 +4,7 @@ package workspace
 
 import (
 	"errors"
+	"strings"
 	"syscall"
 )
 
@@ -19,3 +20,19 @@ const errorInvalidName = syscall.Errno(0x7b)
 func isInvalidLocalNameError(err error) bool {
 	return errors.Is(err, errorInvalidName)
 }
+
+// reservedNameChars are the characters that are illegal in a Windows filename.
+// https://learn.microsoft.com/en-us/windows/win32/fileio/naming-a-file
+const reservedNameChars = `<>:"/\|?*`
+
+// sanitizeLocalName replaces characters that are illegal in a Windows filename
+// (the reserved set plus ASCII control characters) with '_' so an object whose
+// name is invalid locally can still be written under a legal name.
+func sanitizeLocalName(name string) string {
+	return strings.Map(func(r rune) rune {
+		if r < 0x20 || strings.ContainsRune(reservedNameChars, r) {
+			return '_'
+		}
+		return r
+	}, name)
+}
diff --git a/cmd/workspace/workspace/export_dir_windows_test.go b/cmd/workspace/workspace/export_dir_windows_test.go
index aba1e735aa4..9bdd3e67086 100644
--- a/cmd/workspace/workspace/export_dir_windows_test.go
+++ b/cmd/workspace/workspace/export_dir_windows_test.go
@@ -54,3 +54,38 @@ func TestIsInvalidLocalNameError(t *testing.T) {
 		})
 	}
 }
+
+func TestSanitizeLocalName(t *testing.T) {
+	tests := []struct {
+		name string
+		in   string
+		want string
+	}{
+		{
+			name: "colons replaced",
+			in:   "New Notebook 2026-05-04 13:54:24.py",
+			want: "New Notebook 2026-05-04 13_54_24.py",
+		},
+		{
+			name: "all reserved characters replaced",
+			in:   `a<b>c:d"e|f?g*h`,
+			want: "a_b_c_d_e_f_g_h",
+		},
+		{
+			name: "control character replaced",
+			in:   "a\tb",
+			want: "a_b",
+		},
+		{
+			name: "legal name unchanged",
+			in:   "hello world.py",
+			want: "hello world.py",
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			assert.Equal(t, tt.want, sanitizeLocalName(tt.in))
+		})
+	}
+}

From 44366dde17c21457b35cd27f5a4b13454b54c7bb Mon Sep 17 00:00:00 2001
From: Rada Kamysheva <rada.kamysheva@databricks.com>
Date: Tue, 23 Jun 2026 11:59:24 +0000
Subject: [PATCH 8/9] acc: address review on export-dir illegal-filename test

Rename the fixture notebook to "New Notebook a:b" so the acceptance
timestamp redaction no longer applies and the golden stays literal.
Drop the unreachable control-character branch in sanitizeLocalName,
since workspace object names cannot contain control characters.
---
 .../cmd/workspace/export-dir-illegal-filename/_script      | 7 ++++---
 .../workspace/export-dir-illegal-filename/posix/output.txt | 2 +-
 .../export-dir-illegal-filename/windows/output.txt         | 4 ++--
 cmd/workspace/workspace/export_dir_windows.go              | 6 +++---
 cmd/workspace/workspace/export_dir_windows_test.go         | 5 -----
 5 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/_script b/acceptance/cmd/workspace/export-dir-illegal-filename/_script
index 50af95c6962..705b8394d07 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/_script
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/_script
@@ -1,9 +1,10 @@
 # Shared by the posix/ and windows/ leaf tests, which differ only in their GOOS
 # gate and golden output. The notebook name contains ':', which is a legal local
 # filename character on Linux/macOS but illegal on Windows, so export-dir renames
-# it to a legal name with a warning on Windows and exports it normally elsewhere
-# (databricks/cli#5171).
-$CLI workspace import "/test-dir/New Notebook 2026-05-04 13:54:24.py" --file "$TESTDIR/../notebook.py" --format AUTO --language PYTHON
+# it to a legal name with a warning on Windows and exports it normally elsewhere.
+# The real #5171 trigger is the auto-generated "New Notebook <timestamp>" name;
+# we use a plain "a:b" here so the timestamp redaction doesn't obscure the golden.
+$CLI workspace import "/test-dir/New Notebook a:b.py" --file "$TESTDIR/../notebook.py" --format AUTO --language PYTHON
 
 mkdir -p "$TEST_TMP_DIR/export"
 
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/posix/output.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/posix/output.txt
index 846fd8cab36..5bf32c52229 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/posix/output.txt
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/posix/output.txt
@@ -1,5 +1,5 @@
 
 >>> [CLI] workspace export-dir /test-dir [TEST_TMP_DIR]/export
 Exporting files from /test-dir
-/test-dir/New Notebook [TIMESTAMP] -> [TEST_TMP_DIR]/export/New Notebook [TIMESTAMP].py
+/test-dir/New Notebook a:b -> [TEST_TMP_DIR]/export/New Notebook a:b.py
 Export complete
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt
index 7cde3c92f51..554ac73434d 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt
@@ -1,6 +1,6 @@
 
 >>> [CLI] workspace export-dir /test-dir [TEST_TMP_DIR]/export
 Exporting files from /test-dir
-Warn: /test-dir/New Notebook [TIMESTAMP]: name is not valid for the local file system, exporting as "New Notebook 2026-05-04 13_54_24.py"
-/test-dir/New Notebook [TIMESTAMP] -> [TEST_TMP_DIR]\export\New Notebook 2026-05-04 13_54_24.py
+Warn: /test-dir/New Notebook a:b: name is not valid for the local file system, exporting as "New Notebook a_b.py"
+/test-dir/New Notebook a:b -> [TEST_TMP_DIR]\export\New Notebook a_b.py
 Export complete
diff --git a/cmd/workspace/workspace/export_dir_windows.go b/cmd/workspace/workspace/export_dir_windows.go
index 40881e0d4e1..358846ca1e3 100644
--- a/cmd/workspace/workspace/export_dir_windows.go
+++ b/cmd/workspace/workspace/export_dir_windows.go
@@ -26,11 +26,11 @@ func isInvalidLocalNameError(err error) bool {
 const reservedNameChars = `<>:"/\|?*`
 
 // sanitizeLocalName replaces characters that are illegal in a Windows filename
-// (the reserved set plus ASCII control characters) with '_' so an object whose
-// name is invalid locally can still be written under a legal name.
+// with '_' so an object whose name is invalid locally can still be written under
+// a legal name.
 func sanitizeLocalName(name string) string {
 	return strings.Map(func(r rune) rune {
-		if r < 0x20 || strings.ContainsRune(reservedNameChars, r) {
+		if strings.ContainsRune(reservedNameChars, r) {
 			return '_'
 		}
 		return r
diff --git a/cmd/workspace/workspace/export_dir_windows_test.go b/cmd/workspace/workspace/export_dir_windows_test.go
index 9bdd3e67086..1a26f47383e 100644
--- a/cmd/workspace/workspace/export_dir_windows_test.go
+++ b/cmd/workspace/workspace/export_dir_windows_test.go
@@ -71,11 +71,6 @@ func TestSanitizeLocalName(t *testing.T) {
 			in:   `a<b>c:d"e|f?g*h`,
 			want: "a_b_c_d_e_f_g_h",
 		},
-		{
-			name: "control character replaced",
-			in:   "a\tb",
-			want: "a_b",
-		},
 		{
 			name: "legal name unchanged",
 			in:   "hello world.py",

From ce5e23d832cb314312cc3764b3e8d0f3cb7556c9 Mon Sep 17 00:00:00 2001
From: Rada Kamysheva <rada.kamysheva@databricks.com>
Date: Tue, 23 Jun 2026 12:55:52 +0000
Subject: [PATCH 9/9] acc: use two-colon name in export-dir illegal-filename
 test

A single ':' is the Windows alternate-data-stream separator, so
os.Create("New Notebook a:b.py") silently succeeds (writing stream
"b.py") instead of failing with ERROR_INVALID_NAME, leaving the Windows
golden unreproducible. Real #5171 names ("13:54:24") fail because they
contain two colons, which makes the stream type invalid. Switch the
fixture to "a:b:c" so it genuinely triggers the rename-with-warning path
on Windows, matching the unit test, while staying clear of the timestamp
redaction.
---
 .../cmd/workspace/export-dir-illegal-filename/_script  | 10 +++++++---
 .../export-dir-illegal-filename/posix/output.txt       |  2 +-
 .../export-dir-illegal-filename/windows/output.txt     |  4 ++--
 3 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/_script b/acceptance/cmd/workspace/export-dir-illegal-filename/_script
index 705b8394d07..8515606362c 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/_script
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/_script
@@ -2,9 +2,13 @@
 # gate and golden output. The notebook name contains ':', which is a legal local
 # filename character on Linux/macOS but illegal on Windows, so export-dir renames
 # it to a legal name with a warning on Windows and exports it normally elsewhere.
-# The real #5171 trigger is the auto-generated "New Notebook <timestamp>" name;
-# we use a plain "a:b" here so the timestamp redaction doesn't obscure the golden.
-$CLI workspace import "/test-dir/New Notebook a:b.py" --file "$TESTDIR/../notebook.py" --format AUTO --language PYTHON
+# The real #5171 trigger is the auto-generated "New Notebook <timestamp>" name.
+# We use two colons ("a:b:c") rather than one: a single ':' is the Windows
+# alternate-data-stream separator, so os.Create("New Notebook a:b.py") silently
+# succeeds (writing stream "b.py") instead of failing with ERROR_INVALID_NAME.
+# Two colons make the stream type invalid, which is what real timestamp names
+# ("13:54:24") hit. A plain name keeps the timestamp redaction out of the golden.
+$CLI workspace import "/test-dir/New Notebook a:b:c.py" --file "$TESTDIR/../notebook.py" --format AUTO --language PYTHON
 
 mkdir -p "$TEST_TMP_DIR/export"
 
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/posix/output.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/posix/output.txt
index 5bf32c52229..c540d77622e 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/posix/output.txt
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/posix/output.txt
@@ -1,5 +1,5 @@
 
 >>> [CLI] workspace export-dir /test-dir [TEST_TMP_DIR]/export
 Exporting files from /test-dir
-/test-dir/New Notebook a:b -> [TEST_TMP_DIR]/export/New Notebook a:b.py
+/test-dir/New Notebook a:b:c -> [TEST_TMP_DIR]/export/New Notebook a:b:c.py
 Export complete
diff --git a/acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt
index 554ac73434d..e2d1f680ddf 100644
--- a/acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt
+++ b/acceptance/cmd/workspace/export-dir-illegal-filename/windows/output.txt
@@ -1,6 +1,6 @@
 
 >>> [CLI] workspace export-dir /test-dir [TEST_TMP_DIR]/export
 Exporting files from /test-dir
-Warn: /test-dir/New Notebook a:b: name is not valid for the local file system, exporting as "New Notebook a_b.py"
-/test-dir/New Notebook a:b -> [TEST_TMP_DIR]\export\New Notebook a_b.py
+Warn: /test-dir/New Notebook a:b:c: name is not valid for the local file system, exporting as "New Notebook a_b_c.py"
+/test-dir/New Notebook a:b:c -> [TEST_TMP_DIR]\export\New Notebook a_b_c.py
 Export complete