From eda5abad72da6c6f33fb2dc28518c4bbb08f5089 Mon Sep 17 00:00:00 2001
From: Metin Cakircali <metin.cakircali@ecmwf.int>
Date: Thu, 21 May 2026 17:51:52 +0200
Subject: [PATCH 01/10] shallow clone

---
 cmake/ecbuild_git.cmake | 24 +++++++++++++++++++-----
 1 file changed, 19 insertions(+), 5 deletions(-)

diff --git a/cmake/ecbuild_git.cmake b/cmake/ecbuild_git.cmake
index 13763c17..cc8eaf10 100644
--- a/cmake/ecbuild_git.cmake
+++ b/cmake/ecbuild_git.cmake
@@ -64,7 +64,7 @@ endif()
 
 function( ecbuild_git )
 
-  set( options UPDATE NOREMOTE MANUAL RECURSIVE )
+  set( options UPDATE NOREMOTE MANUAL RECURSIVE SHALLOW )
   set( single_value_args PROJECT DIR URL TAG BRANCH )
   set( multi_value_args )
   cmake_parse_arguments( _PAR "${options}" "${single_value_args}" "${multi_value_args}" ${_FIRST_ARG} ${ARGN} )
@@ -98,13 +98,23 @@ function( ecbuild_git )
 
     if( NOT EXISTS "${_PAR_DIR}" )
 
+      set( _clone_args )
+      if( _PAR_SHALLOW )
+        list( APPEND _clone_args "--depth" "1" )
+        if( DEFINED _PAR_BRANCH )
+          list( APPEND _clone_args "--branch" "${_PAR_BRANCH}" )
+        elseif( DEFINED _PAR_TAG )
+          list( APPEND _clone_args "--branch" "${_PAR_TAG}" )
+        endif()
+      endif()
+
       ecbuild_info( "Cloning ${_PAR_PROJECT} from ${_PAR_URL} into ${_PAR_DIR}...")
       execute_process(
-        COMMAND ${GIT_EXECUTABLE} "clone" ${_PAR_URL} ${clone_args} ${_PAR_DIR} "-q"
+        COMMAND ${GIT_EXECUTABLE} "clone" ${_PAR_URL} ${_clone_args} ${_PAR_DIR} "-q"
         RESULT_VARIABLE nok ERROR_VARIABLE error
         WORKING_DIRECTORY "${PARENT_DIR}")
       if(nok)
-        ecbuild_critical("${_PAR_DIR} git clone failed:\n  ${GIT_EXECUTABLE} clone ${_PAR_URL} ${clone_args} ${_PAR_DIR} -q\n  ${error}\n")
+        ecbuild_critical("${_PAR_DIR} git clone failed:\n  ${GIT_EXECUTABLE} clone ${_PAR_URL} ${_clone_args} ${_PAR_DIR} -q\n  ${error}\n")
       endif()
       ecbuild_info( "${_PAR_DIR} retrieved.")
       set( _needs_switch 1 )
@@ -235,8 +245,12 @@ function( ecbuild_git )
       endif() ####################################################################################
 
       if( _PAR_RECURSIVE )
-        ecbuild_info("git submodule --quiet update --init --recursive @ ${ABS_PAR_DIR}")
-        execute_process( COMMAND "${GIT_EXECUTABLE}" submodule --quiet update --init --recursive
+        set( _submodule_args submodule --quiet update --init --recursive )
+        if( _PAR_SHALLOW )
+          list( APPEND _submodule_args "--depth" "1" )
+        endif()
+        ecbuild_info("git ${_submodule_args} @ ${ABS_PAR_DIR}")
+        execute_process( COMMAND "${GIT_EXECUTABLE}" ${_submodule_args}
                         RESULT_VARIABLE nok ERROR_VARIABLE error
                         WORKING_DIRECTORY "${ABS_PAR_DIR}")
         if(nok)

From c04134a5021bb7e66b4bb088aa480e3fa96ce7ab Mon Sep 17 00:00:00 2001
From: Metin Cakircali <metin.cakircali@ecmwf.int>
Date: Thu, 21 May 2026 18:59:49 +0200
Subject: [PATCH 02/10] add doc for shallow option

---
 cmake/ecbuild_git.cmake | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/cmake/ecbuild_git.cmake b/cmake/ecbuild_git.cmake
index cc8eaf10..49331a25 100644
--- a/cmake/ecbuild_git.cmake
+++ b/cmake/ecbuild_git.cmake
@@ -28,7 +28,8 @@ endif()
 #                [ BRANCH <gitbranch> | TAG <gittag> ]
 #                [ UPDATE | NOREMOTE ]
 #                [ MANUAL ]
-#                [ RECURSIVE ] )
+#                [ RECURSIVE ]
+#                [ SHALLOW ] )
 #
 # Options
 # -------
@@ -60,6 +61,10 @@ endif()
 # RECURSIVE : optional
 #   Do a recursive fetch or update
 #
+# SHALLOW : optional
+#   Do a shallow clone (``--depth 1``) on initial checkout.
+#   When combined with RECURSIVE, submodules are also fetched at depth 1.
+#
 ##############################################################################
 
 function( ecbuild_git )

From 39b22d3feb15f9a45aaff621b74af5adc3a3091e Mon Sep 17 00:00:00 2001
From: Metin Cakircali <metin.cakircali@ecmwf.int>
Date: Thu, 21 May 2026 19:10:01 +0200
Subject: [PATCH 03/10] skip fetch and pull when shallow

---
 cmake/ecbuild_git.cmake | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/cmake/ecbuild_git.cmake b/cmake/ecbuild_git.cmake
index 49331a25..1d4fafdf 100644
--- a/cmake/ecbuild_git.cmake
+++ b/cmake/ecbuild_git.cmake
@@ -204,7 +204,9 @@ function( ecbuild_git )
 
       # fetching latest tags and branches
 
-      if( NOT _PAR_NOREMOTE )
+      if( _PAR_SHALLOW )
+        ecbuild_info("${_PAR_DIR} is SHALLOW : Skipping fetch")
+      elseif( NOT _PAR_NOREMOTE )
 
         ecbuild_info("git fetch --all @ ${ABS_PAR_DIR}")
         execute_process( COMMAND "${GIT_EXECUTABLE}" fetch --all -q
@@ -236,10 +238,11 @@ function( ecbuild_git )
         ecbuild_critical("git checkout ${_gitref} on ${_PAR_DIR} failed:\n  ${GIT_EXECUTABLE} checkout -q ${_gitref}\n  ${error}")
       endif()
 
-      if( DEFINED _PAR_BRANCH AND _PAR_UPDATE ) #############################################################################
+      if( DEFINED _PAR_BRANCH AND _PAR_UPDATE AND NOT _PAR_SHALLOW ) #############################
 
         # Use git pull --ff-only, we WANT this to fail on upstream rebase and
         # we DON'T want merge commits here!
+        # Skipped for SHALLOW clones to avoid deepening history.
         execute_process( COMMAND "${GIT_EXECUTABLE}" pull -q --ff-only
                          RESULT_VARIABLE nok ERROR_VARIABLE error
                          WORKING_DIRECTORY "${ABS_PAR_DIR}")

From d543574ebcd77c9bf07ba2c1cec066a54faf6b5d Mon Sep 17 00:00:00 2001
From: Metin Cakircali <metin.cakircali@ecmwf.int>
Date: Thu, 21 May 2026 19:43:53 +0200
Subject: [PATCH 04/10] add doc for shallow option to ecbuild_bundle

---
 cmake/ecbuild_bundle.cmake | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/cmake/ecbuild_bundle.cmake b/cmake/ecbuild_bundle.cmake
index c68e5213..a6d0535d 100644
--- a/cmake/ecbuild_bundle.cmake
+++ b/cmake/ecbuild_bundle.cmake
@@ -66,7 +66,8 @@ endmacro()
 #                   [ BRANCH <gitbranch> | TAG <gittag> ]
 #                   [ UPDATE | NOREMOTE ]
 #                   [ MANUAL ]
-#                   [ RECURSIVE ] )
+#                   [ RECURSIVE ]
+#                   [ SHALLOW ] )
 #
 # Options
 # -------
@@ -101,6 +102,9 @@ endmacro()
 # RECURSIVE : optional
 #   Do a recursive fetch or update
 #
+# SHALLOW : optional
+#   Do a shallow clone (depth=1). See ``ecbuild_git`` for details.
+#
 # Usage
 # -----
 #

From bdacb96d9e77d4d92df92ae27b438a2c3eacf96c Mon Sep 17 00:00:00 2001
From: Metin Cakircali <metin.cakircali@ecmwf.int>
Date: Fri, 22 May 2026 09:32:12 +0200
Subject: [PATCH 05/10] guard commit id for shallow

---
 cmake/ecbuild_git.cmake | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/cmake/ecbuild_git.cmake b/cmake/ecbuild_git.cmake
index 1d4fafdf..93d6e5fc 100644
--- a/cmake/ecbuild_git.cmake
+++ b/cmake/ecbuild_git.cmake
@@ -64,6 +64,7 @@ endif()
 # SHALLOW : optional
 #   Do a shallow clone (``--depth 1``) on initial checkout.
 #   When combined with RECURSIVE, submodules are also fetched at depth 1.
+#   Cannot be combined with TAG when it's a commit ID (SHA)
 #
 ##############################################################################
 
@@ -86,6 +87,13 @@ function( ecbuild_git )
     ecbuild_critical("Unknown keywords given to ecbuild_git(): \"${_PAR_UNPARSED_ARGUMENTS}\"")
   endif()
 
+  if( _PAR_SHALLOW AND DEFINED _PAR_TAG )
+    string(LENGTH "${_PAR_TAG}" _tag_len)
+    if( _tag_len GREATER_EQUAL 7 AND _tag_len LESS_EQUAL 40 AND _PAR_TAG MATCHES "^[0-9a-fA-F]+$" )
+      ecbuild_critical("SHALLOW cloning cannot be used: TAG (${_PAR_TAG}) looks like a commit ID (SHA)!")
+    endif()
+  endif()
+
   if( ECBUILD_GIT )
 
     set( _needs_switch 0 )

From f20d7f2465f5c9c7c4c056afa2e9581ed868c125 Mon Sep 17 00:00:00 2001
From: Metin Cakircali <metin.cakircali@ecmwf.int>
Date: Fri, 22 May 2026 09:48:13 +0200
Subject: [PATCH 06/10] guard switching for shallow

---
 cmake/ecbuild_git.cmake | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/cmake/ecbuild_git.cmake b/cmake/ecbuild_git.cmake
index 93d6e5fc..69ba1af9 100644
--- a/cmake/ecbuild_git.cmake
+++ b/cmake/ecbuild_git.cmake
@@ -64,7 +64,8 @@ endif()
 # SHALLOW : optional
 #   Do a shallow clone (``--depth 1``) on initial checkout.
 #   When combined with RECURSIVE, submodules are also fetched at depth 1.
-#   Cannot be combined with TAG when it's a commit ID (SHA)
+#   Cannot be combined with TAG when it's a commit ID (SHA).
+#   SHALLOW is not switchable and will fail if UPDATE is requested on an existing shallow clone.
 #
 ##############################################################################
 
@@ -97,6 +98,7 @@ function( ecbuild_git )
   if( ECBUILD_GIT )
 
     set( _needs_switch 0 )
+    set( _created_repo 0 )
 
     get_filename_component( ABS_PAR_DIR "${_PAR_DIR}" ABSOLUTE )
     get_filename_component( PARENT_DIR  "${_PAR_DIR}/.." ABSOLUTE )
@@ -130,6 +132,7 @@ function( ecbuild_git )
         ecbuild_critical("${_PAR_DIR} git clone failed:\n  ${GIT_EXECUTABLE} clone ${_PAR_URL} ${_clone_args} ${_PAR_DIR} -q\n  ${error}\n")
       endif()
       ecbuild_info( "${_PAR_DIR} retrieved.")
+      set( _created_repo 1 )
       set( _needs_switch 1 )
 
     endif()
@@ -187,6 +190,10 @@ function( ecbuild_git )
       set( _needs_switch 1 )
     endif()
 
+    if( _PAR_SHALLOW AND _needs_switch AND NOT _created_repo )
+      ecbuild_critical("SHALLOW repository ${_PAR_DIR} is not switchable.")
+    endif()
+
     if( DEFINED _PAR_BRANCH AND _PAR_UPDATE AND NOT _PAR_NOREMOTE )
 
       add_custom_target( git_update_${_PAR_PROJECT}

From c8811ce4b0d1cdafd2d8f0aed28e93674a123fcf Mon Sep 17 00:00:00 2001
From: Metin Cakircali <metin.cakircali@ecmwf.int>
Date: Fri, 22 May 2026 15:01:30 +0200
Subject: [PATCH 07/10] guard pull for shallow

---
 cmake/ecbuild_git.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/cmake/ecbuild_git.cmake b/cmake/ecbuild_git.cmake
index 69ba1af9..54bb3bdc 100644
--- a/cmake/ecbuild_git.cmake
+++ b/cmake/ecbuild_git.cmake
@@ -194,7 +194,7 @@ function( ecbuild_git )
       ecbuild_critical("SHALLOW repository ${_PAR_DIR} is not switchable.")
     endif()
 
-    if( DEFINED _PAR_BRANCH AND _PAR_UPDATE AND NOT _PAR_NOREMOTE )
+    if( DEFINED _PAR_BRANCH AND _PAR_UPDATE AND NOT _PAR_NOREMOTE AND NOT _PAR_SHALLOW )
 
       add_custom_target( git_update_${_PAR_PROJECT}
                          COMMAND "${GIT_EXECUTABLE}" pull -q

From d9a0d6608fcfe2f5f3260c4a635802fb09707e6d Mon Sep 17 00:00:00 2001
From: Marcos Bento <Marcos.Bento@ecmwf.int>
Date: Wed, 27 May 2026 11:15:22 +0100
Subject: [PATCH 08/10] Add test for ecbuild_bundle with shallow option

---
 tests/CMakeLists.txt                          |   1 +
 tests/ecbuild_bundle_shallow/CMakeLists.txt   |  10 ++
 tests/ecbuild_bundle_shallow/run-test.sh      |  62 +++++++++
 .../setup-umbrella-bundle.sh                  |  44 +++++++
 .../setup-umbrella-project.sh                 | 118 ++++++++++++++++++
 5 files changed, 235 insertions(+)
 create mode 100644 tests/ecbuild_bundle_shallow/CMakeLists.txt
 create mode 100755 tests/ecbuild_bundle_shallow/run-test.sh
 create mode 100644 tests/ecbuild_bundle_shallow/setup-umbrella-bundle.sh
 create mode 100644 tests/ecbuild_bundle_shallow/setup-umbrella-project.sh

diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index d6b82683..9cecbc06 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -7,6 +7,7 @@ add_subdirectory( ecbuild_remove_fortran_flags ) # ECBUILD-484
 add_subdirectory( ecbuild_add_option )
 add_subdirectory( ecbuild_add_option_multiproject_defaults )
 add_subdirectory( ecbuild_add_flags )
+add_subdirectory( ecbuild_bundle_shallow )
 add_subdirectory( ecbuild_find_package )
 add_subdirectory( ecbuild_find_python )
 add_subdirectory( find_ecbuild )
diff --git a/tests/ecbuild_bundle_shallow/CMakeLists.txt b/tests/ecbuild_bundle_shallow/CMakeLists.txt
new file mode 100644
index 00000000..74a82e34
--- /dev/null
+++ b/tests/ecbuild_bundle_shallow/CMakeLists.txt
@@ -0,0 +1,10 @@
+
+ecbuild_add_test(
+  TARGET     test_ecbuild_bundle_shallow
+  TYPE       SCRIPT
+  COMMAND    ${CMAKE_CURRENT_SOURCE_DIR}/run-test.sh
+  ENVIRONMENT
+    CMAKE_SOURCE_DIR=${CMAKE_SOURCE_DIR}
+    CMAKE_CURRENT_SOURCE_DIR=${CMAKE_CURRENT_SOURCE_DIR}
+    CMAKE_CURRENT_BINARY_DIR=${CMAKE_CURRENT_BINARY_DIR}
+)
diff --git a/tests/ecbuild_bundle_shallow/run-test.sh b/tests/ecbuild_bundle_shallow/run-test.sh
new file mode 100755
index 00000000..12d415e1
--- /dev/null
+++ b/tests/ecbuild_bundle_shallow/run-test.sh
@@ -0,0 +1,62 @@
+#!/usr/bin/env bash
+
+set -e
+set -x
+
+HERE="$( cd $( dirname "${BASH_SOURCE[0]}" ) && pwd -P )"
+
+ECBUILD_PATH=${CMAKE_SOURCE_DIR}/bin
+SOURCE_TEST_DIR=${CMAKE_CURRENT_SOURCE_DIR}
+BINARY_TEST_DIR=${CMAKE_CURRENT_BINARY_DIR}
+
+# Git 2.38.1+ blocks local file:// submodule clones by default.
+# Allow them for the duration of this script only.
+export GIT_CONFIG_COUNT=1
+export GIT_CONFIG_KEY_0=protocol.file.allow
+export GIT_CONFIG_VALUE_0=always
+
+# Add ecbuild to path
+export PATH=$ECBUILD_PATH:$PATH
+
+# ---- cleanup -----------------------------------------
+rm -rf "${BINARY_TEST_DIR}/workspace"
+
+# ---- setup umbrella project (with submodules) --------
+cd "${BINARY_TEST_DIR}"
+bash "${SOURCE_TEST_DIR}/setup-umbrella-project.sh" \
+          "${BINARY_TEST_DIR}/workspace/projects"
+
+# ---- setup umbrella bundle ---------------------------
+cd "${BINARY_TEST_DIR}"
+bash "${SOURCE_TEST_DIR}/setup-umbrella-bundle.sh" \
+          "${BINARY_TEST_DIR}/workspace/bundle" \
+          "${BINARY_TEST_DIR}/workspace/projects/umbrella"
+
+# ---- configure umbrella bundle -----------------------
+cd ${BINARY_TEST_DIR}/workspace
+mkdir build
+cd build
+ecbuild --prefix=$(pwd)/install -- ../bundle
+
+# ---- check shallowness (umbrella) --------------------
+cd ${BINARY_TEST_DIR}/workspace/bundle/umbrella
+
+if [[ "$(git rev-parse --is-shallow-repository)" == "true" ]]; then
+    echo "Submodule is shallow: PASS"
+    exit 0
+else
+    echo "Submodule is not shallow: FAIL"
+    exit 1
+fi
+
+# ---- check shallowness (umbrella submodules) ---------
+for sub in alpha beta gamma; do
+    cd "${BINARY_TEST_DIR}/workspace/bundle/umbrella/${sub}"
+
+    if [[ "$(git rev-parse --is-shallow-repository)" == "true" ]]; then
+        echo "Submodule $sub is shallow: PASS"
+    else
+        echo "Submodule $sub is not shallow: FAIL"
+        exit 1
+    fi
+done
diff --git a/tests/ecbuild_bundle_shallow/setup-umbrella-bundle.sh b/tests/ecbuild_bundle_shallow/setup-umbrella-bundle.sh
new file mode 100644
index 00000000..13c6e139
--- /dev/null
+++ b/tests/ecbuild_bundle_shallow/setup-umbrella-bundle.sh
@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+
+set -e
+set -u
+set -o pipefail
+
+# ─────────────────────────────────────────────
+# Configuration
+# ─────────────────────────────────────────────
+BASE_DIR="${1:-$(pwd)/bundle}"
+UMBRELLA_DIR="${2:-$(pwd)/projects/umbrella}"
+
+echo "==> Creating bundle workspace at: $BASE_DIR"
+mkdir -p "$BASE_DIR"
+cd "$BASE_DIR"
+
+# ─────────────────────────────────────────────
+# Create the umbrella bundle
+# ─────────────────────────────────────────────
+cat > CMakeLists.txt <<EOF
+
+cmake_minimum_required(VERSION 3.18 FATAL_ERROR)
+
+find_package( ecbuild 3.12 REQUIRED HINTS ${CMAKE_SOURCE_DIR} )
+
+project( umbrella-bundle LANGUAGES NONE )
+
+ecbuild_bundle_initialize()
+
+ecbuild_bundle(
+  PROJECT umbrella
+  GIT "${UMBRELLA_DIR}"
+  BRANCH main
+  RECURSIVE
+  SHALLOW
+)
+
+ecbuild_bundle_finalize()
+
+EOF
+
+cat > VERSION <<EOF
+0.0.1
+EOF
diff --git a/tests/ecbuild_bundle_shallow/setup-umbrella-project.sh b/tests/ecbuild_bundle_shallow/setup-umbrella-project.sh
new file mode 100644
index 00000000..4aed86de
--- /dev/null
+++ b/tests/ecbuild_bundle_shallow/setup-umbrella-project.sh
@@ -0,0 +1,118 @@
+#!/usr/bin/env bash
+
+set -e
+set -u
+set -o pipefail
+
+# ─────────────────────────────────────────────
+# Configuration
+# ─────────────────────────────────────────────
+BASE_DIR="${1:-$(pwd)/projects}"
+
+PROJECTS=(alpha beta gamma)
+UMBRELLA="umbrella"
+
+echo "==> Creating workspace at: $BASE_DIR"
+mkdir -p "$BASE_DIR"
+cd "$BASE_DIR"
+
+# ─────────────────────────────────────────────
+# Helper: make a commit
+# ─────────────────────────────────────────────
+commit() {
+    git add -A
+    git commit -m "$1"
+}
+
+# ─────────────────────────────────────────────
+# Create the 3 dummy projects
+# ─────────────────────────────────────────────
+for proj in "${PROJECTS[@]}"; do
+    echo ""
+    echo "──> Setting up project: $proj"
+    mkdir -p "$proj"
+    cd "$proj"
+    git init -b main
+    git config user.email "demo@example.com"
+    git config user.name  "Demo User"
+
+    # Initial commit with README
+    cat > README.md <<EOF
+# Project $proj
+EOF
+    commit "Initial commit: add README"
+
+    # Second commit — add a source file
+    mkdir -p src
+    cat > "src/$proj.sh" <<EOF
+#!/usr/bin/env bash
+echo "Hello from $proj!"
+EOF
+    chmod +x "src/$proj.sh"
+    commit "Add src/$proj.sh"
+
+    # Third commit — update README with usage
+    cat >> README.md <<EOF
+## Usage
+
+\`\`\`bash
+bash src/$proj.sh
+\`\`\`
+EOF
+    commit "docs: add usage section to README"
+
+    # Fourth commit — add a config file
+    cat > config.env <<EOF
+PROJECT_NAME=$proj
+VERSION=0.1.0
+ENABLED=true
+EOF
+    commit "Add config.env"
+
+    echo "    $proj: $(git log --oneline | wc -l | tr -d ' ') commits"
+    cd ..
+done
+
+# ─────────────────────────────────────────────
+# Create the umbrella project with submodules
+# ─────────────────────────────────────────────
+echo ""
+echo "──> Setting up umbrella project: $UMBRELLA"
+mkdir -p "$UMBRELLA"
+cd "$UMBRELLA"
+git init -b main
+git config user.email "demo@example.com"
+git config user.name  "Demo User"
+
+# Initial README
+cat > README.md <<EOF
+# Umbrella Project
+EOF
+
+cat > CMakeLists.txt <<EOF
+
+cmake_minimum_required(VERSION 3.18 FATAL_ERROR)
+
+project( umbrella LANGUAGES NONE )
+
+EOF
+
+commit "Initial commit: add README"
+
+# Add each project as a submodule (using absolute local paths)
+for proj in "${PROJECTS[@]}"; do
+    SUBMOD_PATH="$(cd "../$proj" && pwd)"
+    git submodule add "$SUBMOD_PATH" "$proj"
+    echo "    added submodule: modules/$proj  ->  $SUBMOD_PATH"
+done
+commit "Add submodules: alpha, beta, gamma"
+
+# A follow-up commit that records a pinned state
+cat >> README.md <<EOF
+
+## Notes
+
+Submodule remotes point to local sibling directories for demo purposes.
+Replace the URLs in \`.gitmodules\` with real remote URLs before sharing.
+EOF
+commit "docs: note about submodule remote URLs"

From 2914bc92146cbe8a16455451817fabb9c6d0459c Mon Sep 17 00:00:00 2001
From: Metin Cakircali <metin.cakircali@ecmwf.int>
Date: Wed, 27 May 2026 13:13:31 +0200
Subject: [PATCH 09/10] fix test shallow option

---
 .../ecbuild_bundle_shallow/setup-umbrella-bundle.sh |  5 ++++-
 .../setup-umbrella-project.sh                       | 13 +++++++++----
 2 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/tests/ecbuild_bundle_shallow/setup-umbrella-bundle.sh b/tests/ecbuild_bundle_shallow/setup-umbrella-bundle.sh
index 13c6e139..3902ab82 100644
--- a/tests/ecbuild_bundle_shallow/setup-umbrella-bundle.sh
+++ b/tests/ecbuild_bundle_shallow/setup-umbrella-bundle.sh
@@ -17,6 +17,9 @@ cd "$BASE_DIR"
 # ─────────────────────────────────────────────
 # Create the umbrella bundle
 # ─────────────────────────────────────────────
+
+UMBRELLA_GIT="file://$(dirname "${UMBRELLA_DIR}")/../bare-repos/$(basename "${UMBRELLA_DIR}").git"
+
 cat > CMakeLists.txt <<EOF
 
 cmake_minimum_required(VERSION 3.18 FATAL_ERROR)
@@ -29,7 +32,7 @@ ecbuild_bundle_initialize()
 
 ecbuild_bundle(
   PROJECT umbrella
-  GIT "${UMBRELLA_DIR}"
+  GIT "${UMBRELLA_GIT}"
   BRANCH main
   RECURSIVE
   SHALLOW
diff --git a/tests/ecbuild_bundle_shallow/setup-umbrella-project.sh b/tests/ecbuild_bundle_shallow/setup-umbrella-project.sh
index 4aed86de..f81dbf89 100644
--- a/tests/ecbuild_bundle_shallow/setup-umbrella-project.sh
+++ b/tests/ecbuild_bundle_shallow/setup-umbrella-project.sh
@@ -99,11 +99,13 @@ EOF
 
 commit "Initial commit: add README"
 
-# Add each project as a submodule (using absolute local paths)
+# IMPORTANT: create each project as a submodule using file:// URL
+# to honor shallow clones (--depth 1)
+BARE_DIR="$BASE_DIR/../bare-repos"
+mkdir -p "$BARE_DIR"
 for proj in "${PROJECTS[@]}"; do
-    SUBMOD_PATH="$(cd "../$proj" && pwd)"
-    git submodule add "$SUBMOD_PATH" "$proj"
-    echo "    added submodule: modules/$proj  ->  $SUBMOD_PATH"
+    git clone --bare "$BASE_DIR/$proj" "$BARE_DIR/$proj.git" >/dev/null 2>&1
+    git submodule add "file://$BARE_DIR/$proj.git" "$proj"
 done
 commit "Add submodules: alpha, beta, gamma"
 
@@ -116,3 +118,6 @@ Submodule remotes point to local sibling directories for demo purposes.
 Replace the URLs in \`.gitmodules\` with real remote URLs before sharing.
 EOF
 commit "docs: note about submodule remote URLs"
+
+# IMPORTANT: bare repo to ensure shallow clone behavior is honored
+git clone --bare "$(pwd)" "$BARE_DIR/$UMBRELLA.git" >/dev/null 2>&1

From 4a25639bd1d6a5e8185ff6b80a2da031868c9763 Mon Sep 17 00:00:00 2001
From: Metin Cakircali <metin.cakircali@ecmwf.int>
Date: Wed, 27 May 2026 13:25:30 +0200
Subject: [PATCH 10/10] add warning for update + shallow

---
 cmake/ecbuild_git.cmake | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/cmake/ecbuild_git.cmake b/cmake/ecbuild_git.cmake
index 54bb3bdc..6a35113d 100644
--- a/cmake/ecbuild_git.cmake
+++ b/cmake/ecbuild_git.cmake
@@ -84,6 +84,10 @@ function( ecbuild_git )
     ecbuild_critical( "Cannot pass both NOREMOTE and UPDATE in macro ecbuild_git" )
   endif()
 
+  if( _PAR_UPDATE AND _PAR_SHALLOW )
+    ecbuild_warn("UPDATE and SHALLOW conflict — shallow clones aren't switchable; UPDATE may be ignored or fail.")
+  endif()
+
   if(_PAR_UNPARSED_ARGUMENTS)
     ecbuild_critical("Unknown keywords given to ecbuild_git(): \"${_PAR_UNPARSED_ARGUMENTS}\"")
   endif()