show-aur-changes: Add --output-dir and --grep flags

As a fix we also add the missing `-C` flag to `git mktree` which caused
a failure in certain conditions. When this script was initially added it
also missed an entry in the `Makefile` so it never actually got shipped
with the contrib package.

Assisted-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Signed-off-by: Christian Heusel <christian@heusel.eu>

Author: christian-heusel

Makefile

@@ -5,6 +5,7 @@ BINDIR = $(PREFIX)/bin
 BASH_SCRIPTS = \
 	admin/checkservices \
 	aur/review \
+	aur/show-aur-changes \
 	package/greposcope \
 	package/packages-signed-by \
 	package/parse-submodules \

aur/show-aur-changes

@@ -8,48 +8,64 @@ set -euo pipefail
 
 usage() {
   cat <<EOF
-Usage: $(basename "$0") [-d|--diff] [-f|--fetch] [-n|--days <n>] [-m|--meta <path>] [-p|--pattern <glob>] [-r|--repo <path>] [--clone <path>]
+Usage: $(basename "$0") [-d|--diff] [-f|--fetch] [-g|--grep <pattern>] [-n|--days <n>] [-m|--meta <path>] [-o|--output-dir <path>] [-p|--pattern <glob>] [-r|--repo <path>] [--clone <path>]
 
 Find AUR packages modified within a time window whose branches contain changes
 to files matching a given glob pattern.
 
 Options:
-  -d, --diff            Print the effective diff for each matched package
-  -f, --fetch           Sync the local mirror and metadata to the latest state before running
-  -n, --days <n>        Look-back window in days (default: 7)
-  -m, --meta <path>     Path to packages-meta-v1.json (default: packages-meta-v1.json in the aur repo root)
-  -p, --pattern <glob>  File pattern to inspect (default: *)
-  -r, --repo <path>     Path to the AUR git checkout (default: git repo of current directory)
-      --clone <path>    Clone the AUR mono repository to <path> and use it as the repo
-  -h, --help            Show this help text
+  -d, --diff               Print the effective diff for each matched package
+  -f, --fetch              Sync the local mirror and metadata to the latest state before running
+  -g, --grep <pattern>     Only include packages whose diff matches <pattern> (grep -E)
+  -n, --days <n>           Look-back window in days (default: 7)
+  -m, --meta <path>        Path to packages-meta-v1.json (default: packages-meta-v1.json in the aur repo root)
+  -o, --output-dir <path>  Write each package's diff to <path>/<package>.patch
+  -p, --pattern <glob>     File pattern to inspect (default: *)
+  -r, --repo <path>        Path to the AUR git checkout (default: git repo of current directory)
+      --clone <path>       Clone the AUR mono repository to <path> and use it as the repo
+  -h, --help               Show this help text
 
 Examples:
   $(basename "$0") --repo ~/Documents/shared_projects/aur --fetch --diff --days 1
+  $(basename "$0") --repo ~/Documents/shared_projects/aur --output-dir ~/patches --days 1
+  $(basename "$0") --repo ~/Documents/shared_projects/aur --grep "npm install" --days 7
 EOF
 }
 
 SHOW_DIFF=0
 FETCH=0
+GREP_PATTERN=""
 DAYS=7
 META_JSON=""
+OUTPUT_DIR=""
 PATTERN="*"
 REPO_ROOT=""
 CLONE_PATH=""
 while [[ "${1:-}" == -* ]]; do
   case "$1" in
-    -d|--diff)    SHOW_DIFF=1 ;;
-    -f|--fetch)   FETCH=1 ;;
-    -n|--days)    shift; DAYS="$1" ;;
-    -m|--meta)    shift; META_JSON="$1" ;;
-    -p|--pattern) shift; PATTERN="$1" ;;
-    -r|--repo)    shift; REPO_ROOT="$1" ;;
-    --clone)      shift; CLONE_PATH="$1" ;;
-    -h|--help)    usage; exit 0 ;;
+    -d|--diff)       SHOW_DIFF=1 ;;
+    -f|--fetch)      FETCH=1 ;;
+    -g|--grep)       shift; GREP_PATTERN="$1" ;;
+    -n|--days)       shift; DAYS="$1" ;;
+    -m|--meta)       shift; META_JSON="$1" ;;
+    -o|--output-dir) shift; OUTPUT_DIR="$1" ;;
+    -p|--pattern)    shift; PATTERN="$1" ;;
+    -r|--repo)       shift; REPO_ROOT="$1" ;;
+    --clone)         shift; CLONE_PATH="$1" ;;
+    -h|--help)       usage; exit 0 ;;
     *) echo "Unknown flag: $1" >&2; echo >&2; usage >&2; exit 1 ;;
   esac
   shift
 done
 
+if [[ -n "$OUTPUT_DIR" ]]; then
+  if [[ -e "$OUTPUT_DIR" && ! -d "$OUTPUT_DIR" ]]; then
+    echo "error: output-dir '$OUTPUT_DIR' exists but is not a directory" >&2
+    exit 1
+  fi
+  mkdir -p "$OUTPUT_DIR"
+fi
+
 if [[ -n "$CLONE_PATH" ]]; then
   echo "Cloning AUR mono repository to $CLONE_PATH ..." >&2
   git clone "$AUR_REPO_URL" "$CLONE_PATH"
@@ -98,28 +114,44 @@ for pkg in "${PKGS[@]}"; do
   fi
 
   # Check if there are any commits matching $PATTERN for this package since $CUTOFF
-  if git -C "$REPO_ROOT" log "origin/$pkg" --since="$SINCE_DATE" --name-only --format="" -- "$PATTERN" | grep -q .; then
-    echo "$pkg"
-
-    if (( SHOW_DIFF )); then
-      # Find the boundary commits for the range touching $PATTERN
-      mapfile -t commits < <(
-        git -C "$REPO_ROOT" log "origin/$pkg" --since="$SINCE_DATE" --format="%H" -- "$PATTERN"
-      )
-      newest="${commits[0]}"
-      oldest="${commits[-1]}"
-      # Diff from the parent of the oldest in-range commit (empty tree if root)
-      if git -C "$REPO_ROOT" rev-parse "${oldest}^" &>/dev/null; then
-        base="${oldest}^"
-      else
-        # So far this always outputs the magic value
-        # '4b825dc642cb6eb9a060e54bf8d69288fbee4904', but instead of hardcoding
-        # it we regenerate it each time to not rely on it
-        #
-        # https://stackoverflow.com/a/9766506
-        base="$(git mktree < /dev/null)"
-      fi
-      git -C "$REPO_ROOT" diff "$base" "$newest" -- "$PATTERN"
+  if ! git -C "$REPO_ROOT" log "origin/$pkg" --since="$SINCE_DATE" --name-only --format="" -- "$PATTERN" | grep -q .; then
+    continue
+  fi
+
+  diff_output=""
+  if (( SHOW_DIFF )) || [[ -n "$OUTPUT_DIR" ]] || [[ -n "$GREP_PATTERN" ]]; then
+    # Find the boundary commits for the range touching $PATTERN
+    mapfile -t commits < <(
+      git -C "$REPO_ROOT" log "origin/$pkg" --since="$SINCE_DATE" --format="%H" -- "$PATTERN"
+    )
+    newest="${commits[0]}"
+    oldest="${commits[-1]}"
+    # Diff from the parent of the oldest in-range commit (empty tree if root)
+    if git -C "$REPO_ROOT" rev-parse "${oldest}^" &>/dev/null; then
+      base="${oldest}^"
+    else
+      # So far this always outputs the magic value
+      # '4b825dc642cb6eb9a060e54bf8d69288fbee4904', but instead of hardcoding
+      # it we regenerate it each time to not rely on it
+      #
+      # https://stackoverflow.com/a/9766506
+      base="$(git -C "$REPO_ROOT" mktree < /dev/null)"
     fi
+    diff_output=$(git -C "$REPO_ROOT" diff "$base" "$newest" -- "$PATTERN")
+  fi
+
+  # Match against grep pattern if specified
+  if [[ -n "$GREP_PATTERN" ]] && ! grep -qE "$GREP_PATTERN" <<< "$diff_output"; then
+    continue
+  fi
+
+  echo "$pkg"
+
+  if (( SHOW_DIFF )) && [[ -n "$OUTPUT_DIR" ]]; then
+    printf '%s' "$diff_output" | tee "$OUTPUT_DIR/$pkg.patch"
+  elif (( SHOW_DIFF )); then
+    printf '%s' "$diff_output"
+  elif [[ -n "$OUTPUT_DIR" ]]; then
+    printf '%s' "$diff_output" > "$OUTPUT_DIR/$pkg.patch"
   fi
 done