Fix git-lfs unnecessary hook installation

Fix an issue where git lfs install was running unnecessarily in repositories
without LFS files, causing hooks to be installed when they shouldn't be.

Changes:
- Update src/git-lfs/install.sh to properly check for empty git lfs ls-files output
- Add comprehensive test (test/git-lfs/noLfsFiles.sh) to verify hooks are not installed
  when no LFS files are present
- Update test scenarios to include the new test case

The fix changes the condition from checking command exit status to checking
if the output is empty, preventing unnecessary hook installation in non-LFS repos.

Author: yaegashi

src/git-lfs/install.sh

@@ -265,11 +265,18 @@ if [ "${AUTO_PULL}" != "true" ]; then
     exit 0
 fi
 
-# Check if repo is a git lfs repo.
-if ! git lfs ls-files > /dev/null 2>&1; then
+# Check if repo is a git lfs enabled repo by running 'git lfs ls-files'
+if ! ls_files_output=$(git lfs ls-files 2>&1); then
+    echo "(!) Skipping automatic 'git lfs pull' because 'git lfs ls-files' failed"
+    exit 0
+fi
+
+# Check if 'git lfs ls-files' output is empty
+if [ -z "$ls_files_output" ]; then
     echo "(!) Skipping automatic 'git lfs pull' because no git lfs files were detected"
     exit 0
 fi
+
 git lfs install
 git lfs pull
 EOF

test/git-lfs/noLfsFiles.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+
+set -e
+
+# Test for git-lfs behavior with repos that have no LFS files
+# This tests the fix for the issue where git lfs install was running unnecessarily
+
+# Optional: Import test library
+source dev-container-features-test-lib
+
+# Test that git-lfs is installed
+check "git-lfs version" git-lfs --version
+
+# Test the generated script exists
+check "pull script exists" test -f /usr/local/share/pull-git-lfs-artifacts.sh
+
+# We should already be in a git repository created by initializeCommand
+# Verify we're in a git repository
+check "in git repository" git rev-parse --is-inside-work-tree
+
+# Test that git lfs ls-files returns empty output
+check "git lfs ls-files returns empty output" test -z "$(git lfs ls-files 2>/dev/null)"
+
+# Verify no LFS hooks exist initially (the script should have already run during postCreateCommand)
+HOOKS_COUNT=$(find .git/hooks -type f ! -name '*.sample' | wc -l)
+check "no git hooks installed after postCreateCommand" test "$HOOKS_COUNT" -eq 0
+
+# Double check: specifically look for the hooks that git lfs install would create
+check "no post-merge hook" test ! -f .git/hooks/post-merge
+check "no pre-push hook" test ! -f .git/hooks/pre-push
+check "no post-commit hook" test ! -f .git/hooks/post-commit
+check "no post-checkout hook" test ! -f .git/hooks/post-checkout
+
+# Report results
+reportResults

test/git-lfs/scenarios.json

@@ -19,6 +19,14 @@
             }
         }
     },
+    "noLfsFiles": {
+        "image": "mcr.microsoft.com/devcontainers/base:ubuntu",
+        "initializeCommand": "git init && git config user.email '[email protected]' && git config user.name 'Test User' && echo 'regular file content' > regular.txt && git add regular.txt && git commit -m 'Initial commit without LFS'",
+        "remoteUser": "vscode",
+        "features": {
+            "git-lfs": {}
+        }
+    },
     "use_github": {
         "image": "mcr.microsoft.com/devcontainers/base:ubuntu",
         "remoteUser": "vscode",