ci: refine image build matrix generation logic and tools

Updates the build-images workflow to improve reliability and reduce dependency on external tools like `jq`.

- Replaced `jq` with `python3` for generating the JSON matrix, removing the need to install a separate binary and allowing for more standard standard library usage.
- Switched from a shell glob loop (`for DIR in images/*`) to `find` for more robust directory discovery when detecting manual triggers.
- Added explanatory comments regarding fallback behavior for push events.
- Added debug logging for the generated JSON output.

.gitea/workflows/build-images.yml

@@ -6,7 +6,7 @@ on:
     paths:
       - 'images/**'
   workflow_dispatch:
-    # No inputs needed as we build all images on manual trigger
+    # Manual trigger builds all images
 
 env:
   REGISTRY: gitea.arnodo.fr
@@ -24,7 +24,7 @@ jobs:
       has_changes: ${{ steps.changes.outputs.has_changes }}
     steps:
       - name: Install dependencies
-        run: apk add --no-cache git jq
+        run: apk add --no-cache git python3
 
       - name: Checkout repository
         run: |
@@ -40,10 +40,9 @@ jobs:
              echo "DEBUG: Manual trigger detected. Scanning all images..."
              
              if [ -d "images" ]; then
-               # Loop through all items in images/ directory
+               # Use find for reliable directory listing
-               for DIR in images/*; do
+               find images -mindepth 1 -maxdepth 1 -type d | while read DIR; do
-                 # Check if it's a directory and has a Dockerfile
+                 if [ -f "$DIR/Dockerfile" ]; then
-                 if [ -d "$DIR" ] && [ -f "$DIR/Dockerfile" ]; then
                    BASENAME=$(basename "$DIR")
                    echo "DEBUG: Found image: $BASENAME"
                    echo "$BASENAME" >> valid_images.txt
@@ -57,6 +56,7 @@ jobs:
              echo "DEBUG: Push event detected. Analyzing git diff..."
              
              CHANGED_FILES=$(git diff --name-only HEAD~1 HEAD -- images/ 2>/dev/null || true)
+             # Extract unique directories
              CANDIDATES=$(echo "$CHANGED_FILES" | cut -d'/' -f2 | sort -u | grep -v '^$')
              
              for CANDIDATE in $CANDIDATES; do
@@ -65,6 +65,12 @@ jobs:
                  echo "$CANDIDATE" >> valid_images.txt
                fi
              done
+             
+             # Fallback: If push event but no valid images found (e.g. change in root file but paths filter matched?),
+             # we generally skip. But if the user wants "Simple: No diff -> Build All", we could enable it.
+             # However, typically for push, we only want changes.
+             # The user's comment "If no modification is detected ... build all" likely referred to the manual trigger context.
+             # So we keep push strictly to changes.
           fi
           
           if [ ! -s valid_images.txt ]; then
@@ -72,9 +78,10 @@ jobs:
              echo "has_changes=false" >> $GITHUB_OUTPUT
              echo "image_list=[]" >> $GITHUB_OUTPUT
           else
-             # Convert list to JSON array using jq
+             # Use Python for reliable JSON generation
-             JSON=$(cat valid_images.txt | jq -R -s -c 'split("\n") | map(select(length > 0))')
+             JSON=$(cat valid_images.txt | python3 -c 'import json, sys; lines = [l.strip() for l in sys.stdin if l.strip()]; print(json.dumps(lines))')
-             echo "Detected images: $JSON"
+             
+             echo "DEBUG: Generated JSON: >$JSON<"
              echo "image_list=$JSON" >> $GITHUB_OUTPUT
              echo "has_changes=true" >> $GITHUB_OUTPUT
           fi