fix(hooks): warn when preserved pre-commit hook does not dispatch pre-commit.d (#52)

README.md

@@ -8,7 +8,7 @@ Manage repo-level dependencies with an encrypted manifest and a gitignored clone
 A public observer sees only 'this repo uses modules' — no names, no pinned commits, no count.
 
 ![lang: bash](https://img.shields.io/badge/lang-bash-4EAA25?style=flat&logo=gnubash&logoColor=white)
-[![tests: 136 passing](https://img.shields.io/badge/tests-136%20passing-brightgreen?style=flat)](test/)
+[![tests: 138 passing](https://img.shields.io/badge/tests-138%20passing-brightgreen?style=flat)](test/)
 ![License: MIT](https://img.shields.io/badge/License-MIT-blue?style=flat)
 
 </div>
@@ -122,7 +122,7 @@ cd modules && mise trust && mise install
 mise run test
 ```
 
-**136 tests** across 13 suites, using [BATS](https://github.com/bats-core/bats-core). All tests use local git repos in temp directories — no network, no external dependencies.
+**138 tests** across 13 suites, using [BATS](https://github.com/bats-core/bats-core). All tests use local git repos in temp directories — no network, no external dependencies.
 
 The `git-mechanics` suite verifies git's behavior around gitignored nested repos. The `merge-driver` suite simulates concurrent pin bumps to validate the manifest merge logic. The `roundtrip` suite drives the full setup → add → lock → fresh-clone → unlock → init path end-to-end with git-crypt.
 

lib/hooks.sh

@@ -21,6 +21,12 @@ install_pre_commit_hooks() {
     mkdir -p "$hooks_dst"
     cp "$hooks_src/dispatcher" "$hooks_dst/pre-commit"
     chmod +x "$hooks_dst/pre-commit"
+  elif ! grep -q 'pre-commit\.d' "$hooks_dst/pre-commit" 2>/dev/null; then
+    echo "Warning: existing pre-commit hook at $hooks_dst/pre-commit" >&2
+    echo "         does not dispatch pre-commit.d/. The modules guards were" >&2
+    echo "         installed but may not run until this hook invokes them." >&2
+    echo "  To use the default dispatcher: rm $hooks_dst/pre-commit && mise run install-hooks" >&2
+    echo "  To keep your hook: update it to iterate files in ${hooks_dst}/pre-commit.d/" >&2
   fi
 
   mkdir -p "$hooks_dst/pre-commit.d"

test/hooks.bats

@@ -58,6 +58,40 @@ HOOK
   [ ! -e "$PARENT/.git/hooks/pre-commit.d/path-obfuscation" ]
 }
 
+@test "setup warns when preserved pre-commit does not dispatch pre-commit.d" {
+  local fresh="$BATS_TEST_TMPDIR/no-dispatch"
+  create_parent_repo "$fresh"
+  cat > "$fresh/.git/hooks/pre-commit" <<'EOF'
+#!/usr/bin/env bash
+echo "my custom hook"
+EOF
+  chmod +x "$fresh/.git/hooks/pre-commit"
+
+  export MODULES_CALLER_PWD="$fresh"
+  run modules setup
+
+  [ "$status" -eq 0 ]
+  echo "$output" | grep -q "does not dispatch pre-commit.d"
+}
+
+@test "setup quiet when preserved pre-commit dispatches pre-commit.d" {
+  local fresh="$BATS_TEST_TMPDIR/dispatches"
+  create_parent_repo "$fresh"
+  cat > "$fresh/.git/hooks/pre-commit" <<'DISPATCH'
+#!/usr/bin/env bash
+for hook in "$(dirname "$0")/pre-commit.d"/*; do
+  [ -x "$hook" ] && "$hook" || exit $?
+done
+DISPATCH
+  chmod +x "$fresh/.git/hooks/pre-commit"
+
+  export MODULES_CALLER_PWD="$fresh"
+  run modules setup
+
+  [ "$status" -eq 0 ]
+  ! echo "$output" | grep -q "does not dispatch pre-commit.d"
+}
+
 @test "setup removes obsolete path-obfuscation hook if present" {
   # Simulate upgrading from an old layout where path-obfuscation was installed
   cat > "$PARENT/.git/hooks/pre-commit.d/path-obfuscation" <<'EOF'