From 6a509a53716aecddcbde869caa6fb942ba4c5b45 Mon Sep 17 00:00:00 2001
From: Bob Lail <lail@squareup.com>
Date: Mon, 20 Jul 2026 14:46:06 -0700
Subject: [PATCH] fix: Skip resolving `Subcommands()` if there are no more
 arguments to identify

---
 identification.go      |  5 +++++
 identification_test.go | 37 +++++++++++++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)

diff --git a/identification.go b/identification.go
index c863d1f..36324d4 100644
--- a/identification.go
+++ b/identification.go
@@ -66,6 +66,11 @@ func identify(cmd Command, args []string) (Command, []string, error) {
 			return def, args, nil
 		}
 		return nullCommand{parent: cmd, name: name}, rest, nil
+	} else if len(rest) == 0 {
+		// With no remaining args, there is nothing to descend into, so we don't
+		// resolve found's subcommands. This lets callers like `which` identify
+		// a command even when it doesn't fulfill a discovery contract.
+		return found, rest, nil
 	} else if subcmds, err := found.Subcommands(); err != nil {
 		return found, rest, err
 	} else if len(subcmds) > 0 {
diff --git a/identification_test.go b/identification_test.go
index d76d87f..4842730 100644
--- a/identification_test.go
+++ b/identification_test.go
@@ -1,6 +1,7 @@
 package exoskeleton
 
 import (
+	"errors"
 	"fmt"
 	"testing"
 
@@ -43,6 +44,42 @@ func TestIdentifyByAlias(t *testing.T) {
 	}
 }
 
+// A command discovered via a describe-based contract (e.g. OpenCLI) resolves
+// its subcommands lazily by shelling out. When the target doesn't implement the
+// describe flag, that resolution fails. Identifying such a command with no
+// remaining args must not trigger the resolution — locating the command should
+// not require running its describe flag.
+func TestIdentifyDoesNotResolveSubcommandsWithoutRemainingArgs(t *testing.T) {
+	described := false
+	failing := &executableCommand{
+		name:       "plain",
+		discoverer: &discoverer{},
+		cache:      nullCache{},
+		describe: func(cmd *executableCommand) (*commandDescriptor, error) {
+			described = true
+			return nil, errors.New("plain: error: unknown flag --help-opencli")
+		},
+	}
+
+	help := &builtinCommand{definition: &EmbeddedCommand{Name: `help`}}
+	complete := &builtinCommand{definition: &EmbeddedCommand{Name: `complete`}}
+	entrypoint := &Entrypoint{cmds: Commands{help, complete, failing}}
+
+	// No remaining args: subcommands must not be resolved.
+	cmd, rest, err := entrypoint.Identify([]string{"plain"})
+	assert.NoError(t, err)
+	assert.Equal(t, failing, cmd)
+	assert.Equal(t, []string{}, rest)
+	assert.False(t, described, "should not have attempted to describe the command")
+
+	// With a remaining positional arg, subcommands are resolved to look for a
+	// match — confirming the short-circuit is specific to the empty-rest case.
+	described = false
+	_, _, err = entrypoint.Identify([]string{"plain", "sub"})
+	assert.Error(t, err)
+	assert.True(t, described, "should have attempted to describe the command")
+}
+
 func TestIdentify(t *testing.T) {
 	// all
 	// ├── a