[PATCH v5] add: support pre-add hook
- From
- Chandra Kethi-Reddy via GitGitGadget <gitgitgadget@gmail.com>
- Date
- Mar 5, 2026, 12:37 UTC
- Message-ID
- <pull.2045.v5.git.1772714253412.gitgitgadget@gmail.com>
- In-Reply-To
- <pull.2045.v4.git.1772710566599.gitgitgadget@gmail.com>
From: Chandra Kethi-Reddy <chandrakr@pm.me>
"git add" has no hook that lets users inspect what is about to be staged. Users who want to reject certain paths or content must wrap the command in a shell alias or wait for pre-commit, which fires too late to prevent staging.
Introduce a "pre-add" hook so that users can inspect or reject proposed index updates at staging time.
$1 -- index path used by this invocation (may not exist yet) $2 -- lockfile path containing proposed staged index state
Hook authors can inspect the result with ordinary Git commands:
GIT_INDEX_FILE="$2" git diff --cached --name-only HEAD
Both files should be treated as read-only. Exiting with non-zero status rejects the update and leaves the index unchanged.
The hook accepts or rejects the entire proposed update. Per-path filtering is not supported.
The hook is bypassed with "--no-verify" and is not invoked for --interactive, --patch, --edit, or --dry-run, nor by "git commit -a" which stages through its own code path.
Signed-off-by: Chandra Kethi-Reddy <chandrakr@pm.me>
---
add: support pre-add hook
Summary
=======
* v5 switches from find_hook() to hook_exists() for early hook
detection so hooks configured via core.hooksPath are discovered
* Add a tests exercises config-based hook discovery
* Fixed Windows CI failures with correct path formatting in the
relevant test
Notes
=====
* This design intentionally trades ODB prevention for correctness of
hook inputs: blobs may already be written to object storage when the
hook runs, but hook rejection still leaves the on-disk index
unchanged
* AI Disclosure: Codex and Claude Code CLI were used to assist
drafting. All tests, code, and docs were committed by hand.Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-2045%2Fshatachandra%2Fpre-add-hooks-v5 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-2045/shatachandra/pre-add-hooks-v5 Pull-Request: https://github.com/gitgitgadget/git/pull/2045
Range-diff vs v4:
1: 9383395bb0 ! 1: fc58c4cba2 add: support pre-add hook
@@ builtin/add.c: int cmd_add(int argc,
string_list_clear(&only_match_skip_worktree, 0);
}
-+ if (!show_only && !no_verify && find_hook(repo, "pre-add")) {
++ if (!show_only && !no_verify && hook_exists(repo, "pre-add")) {
+ run_pre_add = 1;
+ orig_index_path = absolute_pathdup(repo_get_index_file(repo));
+ }
@@ t/t3706-pre-add-hook.sh (new)
+ git commit -m "initial"
+'
+
++test_expect_success 'hook found via core.hooksPath' '
++ test_when_finished "git reset --hard &&
++ rm -rf custom-hooks &&
++ git config --unset core.hooksPath" &&
++ mkdir custom-hooks &&
++ write_script custom-hooks/pre-add <<-\EOF &&
++ echo invoked >hook-ran
++ EOF
++ git config core.hooksPath custom-hooks &&
++ echo changed >>file &&
++ git add file &&
++ test_path_is_file hook-ran &&
++ rm -f hook-ran
++'
++
+test_expect_success 'hook receives index-path and lockfile-path arguments' '
+ test_when_finished "git reset --hard &&
+ rm -f staged expect-count arg-count arg-one arg-two \
@@ t/t3706-pre-add-hook.sh (new)
+ EOF
+ echo changed >>file &&
+ GIT_INDEX_FILE=alt-index git add file &&
-+ echo "$PWD/alt-index" >expect-index &&
++ test-tool path-utils absolute_path alt-index >expect-index &&
+ test_cmp expect-index arg-one &&
-+ echo "$PWD/alt-index.lock" >expect-lockpath &&
++ test-tool path-utils absolute_path alt-index.lock >expect-lockpath &&
+ test_cmp expect-lockpath arg-two
+'
+Documentation/git-add.adoc | 10 +- Documentation/githooks.adoc | 30 ++++ builtin/add.c | 38 ++++- read-cache-ll.h | 3 + read-cache.c | 9 +- t/meson.build | 1 + t/t3706-pre-add-hook.sh | 304 ++++++++++++++++++++++++++++++++++++ 7 files changed, 388 insertions(+), 7 deletions(-) create mode 100755 t/t3706-pre-add-hook.sh
diff --git a/Documentation/git-add.adoc b/Documentation/git-add.adoc index 6192daeb03..a3ff4ced83 100644 --- a/Documentation/git-add.adoc +++ b/Documentation/git-add.adoc @@ -11,7 +11,7 @@ SYNOPSIS git add [--verbose | -v] [--dry-run | -n] [--force | -f] [--interactive | -i] [--patch | -p] [--edit | -e] [--[no-]all | -A | --[no-]ignore-removal | [--update | -u]] [--sparse] [--intent-to-add | -N] [--refresh] [--ignore-errors] [--ignore-missing] [--renormalize] - [--chmod=(+|-)x] [--pathspec-from-file=<file> [--pathspec-file-nul]] + [--no-verify] [--chmod=(+|-)x] [--pathspec-from-file=<file> [--pathspec-file-nul]] [--] [<pathspec>...] DESCRIPTION @@ -42,10 +42,11 @@ use the `--force` option to add ignored files. If you specify the exact filename of an ignored file, `git add` will fail with a list of ignored files. Otherwise it will silently ignore the file. +A `pre-add` hook can be used to reject `git add` (see linkgit:githooks[5]). + Please see linkgit:git-commit[1] for alternative ways to add content to a commit. - OPTIONS ------- `<pathspec>...`:: @@ -163,6 +164,10 @@ for `git add --no-all <pathspec>...`, i.e. ignored removed files. Don't add the file(s), but only refresh their stat() information in the index. +`--no-verify`:: + Bypass the `pre-add` hook if it exists. See linkgit:githooks[5] for + more information about hooks. + `--ignore-errors`:: If some files could not be added because of errors indexing them, do not abort the operation, but continue adding the @@ -451,6 +456,7 @@ linkgit:git-reset[1] linkgit:git-mv[1] linkgit:git-commit[1] linkgit:git-update-index[1] +linkgit:githooks[5] GIT --- diff --git a/Documentation/githooks.adoc b/Documentation/githooks.adoc index 056553788d..90945a590e 100644 --- a/Documentation/githooks.adoc +++ b/Documentation/githooks.adoc @@ -94,6 +94,36 @@ and is invoked after the patch is applied and a commit is made. This hook is meant primarily for notification, and cannot affect the outcome of `git am`. +pre-add +~~~~~~~ + +This hook is invoked by linkgit:git-add[1], and can be bypassed with the +`--no-verify` option. It is not invoked for `--interactive`, `--patch`, +`--edit`, or `--dry-run`. + +It takes two arguments: the path to the index file for this invocation +of `git add`, and the path to the lockfile containing the proposed +index after staging. If no index exists yet, the first argument names +a path that does not exist and should be treated as an empty index. + +The hook is invoked after the index has been updated in memory and +written to the lockfile, but before it is committed to the final index +path. Exiting with a non-zero status causes `git add` to reject the +proposed state, roll back the lockfile, and leave the index unchanged. +Exiting with zero status allows the index update to be committed. The +hook accepts or rejects the entire proposed update; per-path filtering +is not supported. Both files should be treated as read-only by the hook. + +Hook authors may set `GIT_INDEX_FILE="$1"` to inspect the current index +state and `GIT_INDEX_FILE="$2"` to inspect the proposed index state. + +This hook can be used to prevent staging of files based on names, content, +or sizes (e.g., to block `.env` files, secret keys, or large files). + +This hook is not invoked by `git commit -a` or `git commit --include` +which still can run the `pre-commit` hook, providing a control point at +commit time. + pre-commit ~~~~~~~~~~ diff --git a/builtin/add.c b/builtin/add.c index 32709794b3..f35994ff0f 100644 --- a/builtin/add.c +++ b/builtin/add.c @@ -25,6 +25,8 @@ #include "strvec.h" #include "submodule.h" #include "add-interactive.h" +#include "hook.h" +#include "abspath.h" static const char * const builtin_add_usage[] = { N_("git add [<options>] [--] <pathspec>..."), @@ -36,6 +38,7 @@ static int take_worktree_changes; static int add_renormalize; static int pathspec_file_nul; static int include_sparse; +static int no_verify; static const char *pathspec_from_file; static int chmod_pathspec(struct repository *repo, @@ -271,6 +274,7 @@ static struct option builtin_add_options[] = { OPT_BOOL( 0 , "refresh", &refresh_only, N_("don't add, only refresh the index")), OPT_BOOL( 0 , "ignore-errors", &ignore_add_errors, N_("just skip files which cannot be added because of errors")), OPT_BOOL( 0 , "ignore-missing", &ignore_missing, N_("check if - even missing - files are ignored in dry run")), + OPT_BOOL( 0 , "no-verify", &no_verify, N_("bypass pre-add hook")), OPT_BOOL(0, "sparse", &include_sparse, N_("allow updating entries outside of the sparse-checkout cone")), OPT_STRING(0, "chmod", &chmod_arg, "(+|-)x", N_("override the executable bit of the listed files")), @@ -391,6 +395,8 @@ int cmd_add(int argc, char *ps_matched = NULL; struct lock_file lock_file = LOCK_INIT; struct odb_transaction *transaction; + int run_pre_add = 0; + char *orig_index_path = NULL; repo_config(repo, add_config, NULL); @@ -576,6 +582,11 @@ int cmd_add(int argc, string_list_clear(&only_match_skip_worktree, 0); } + if (!show_only && !no_verify && hook_exists(repo, "pre-add")) { + run_pre_add = 1; + orig_index_path = absolute_pathdup(repo_get_index_file(repo)); + } + transaction = odb_transaction_begin(repo->objects); ps_matched = xcalloc(pathspec.nr, 1); @@ -598,9 +609,30 @@ int cmd_add(int argc, odb_transaction_commit(transaction); finish: - if (write_locked_index(repo->index, &lock_file, - COMMIT_LOCK | SKIP_IF_UNCHANGED)) - die(_("unable to write new index file")); + if (run_pre_add && repo->index->cache_changed) { + struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT; + + if (write_locked_index(repo->index, &lock_file, + SKIP_INDEX_CHANGE_HOOK)) + die(_("unable to write proposed index")); + + strvec_push(&opt.args, orig_index_path); + strvec_push(&opt.args, get_lock_file_path(&lock_file)); + if (run_hooks_opt(repo, "pre-add", &opt)) { + rollback_lock_file(&lock_file); /* hook rejected */ + exit_status = 1; + } else if (commit_lock_file(&lock_file)) { + die(_("unable to write new index file")); + } else { + emit_post_index_change(repo->index); + } + } else { + if (write_locked_index(repo->index, &lock_file, + COMMIT_LOCK | SKIP_IF_UNCHANGED)) + die(_("unable to write new index file")); + } + + free(orig_index_path); free(ps_matched); dir_clear(&dir); diff --git a/read-cache-ll.h b/read-cache-ll.h index 71b49d9af4..eed1d74d99 100644 --- a/read-cache-ll.h +++ b/read-cache-ll.h @@ -284,6 +284,9 @@ int is_index_unborn(struct index_state *); /* For use with `write_locked_index()`. */ #define COMMIT_LOCK (1 << 0) #define SKIP_IF_UNCHANGED (1 << 1) +#define SKIP_INDEX_CHANGE_HOOK (1 << 2) + +void emit_post_index_change(struct index_state *istate); /* * Write the index while holding an already-taken lock. Close the lock, diff --git a/read-cache.c b/read-cache.c index 0c07c3aef7..dfe8d8e4d7 100644 --- a/read-cache.c +++ b/read-cache.c @@ -3161,13 +3161,18 @@ static int do_write_locked_index(struct index_state *istate, else ret = close_lock_file_gently(lock); + if (!(flags & SKIP_INDEX_CHANGE_HOOK)) + emit_post_index_change(istate); + return ret; +} + +void emit_post_index_change(struct index_state *istate) +{ run_hooks_l(the_repository, "post-index-change", istate->updated_workdir ? "1" : "0", istate->updated_skipworktree ? "1" : "0", NULL); istate->updated_workdir = 0; istate->updated_skipworktree = 0; - - return ret; } static int write_split_index(struct index_state *istate, diff --git a/t/meson.build b/t/meson.build index f80e366cff..2419a9adbb 100644 --- a/t/meson.build +++ b/t/meson.build @@ -415,6 +415,7 @@ integration_tests = [ 't3703-add-magic-pathspec.sh', 't3704-add-pathspec-file.sh', 't3705-add-sparse-checkout.sh', + 't3706-pre-add-hook.sh', 't3800-mktag.sh', 't3900-i18n-commit.sh', 't3901-i18n-patch.sh', diff --git a/t/t3706-pre-add-hook.sh b/t/t3706-pre-add-hook.sh new file mode 100755 index 0000000000..352b79e5d6 --- /dev/null +++ b/t/t3706-pre-add-hook.sh @@ -0,0 +1,304 @@ +#!/bin/sh + +test_description='pre-add hook tests + +These tests run git add with and without pre-add hooks to ensure functionality. Largely derived from t7503 (pre-commit and pre-merge-commit hooks) and t5571 (pre-push hooks).' + +GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main +export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME + +. ./test-lib.sh + +test_expect_success 'with no hook' ' + test_when_finished "rm -f actual" && + echo content >file && + git add file && + test_path_is_missing actual +' + +test_expect_success POSIXPERM 'with non-executable hook' ' + test_when_finished "rm -f actual" && + test_hook pre-add <<-\EOF && + echo should-not-run >>actual + exit 1 + EOF + chmod -x .git/hooks/pre-add && + + echo content >file && + git add file && + test_path_is_missing actual +' + +test_expect_success '--no-verify with no hook' ' + echo content >file && + git add --no-verify file && + test_path_is_missing actual +' + +test_expect_success 'with succeeding hook' ' + test_when_finished "rm -f actual expected" && + echo "pre-add" >expected && + test_hook pre-add <<-\EOF && + echo pre-add >>actual + EOF + + echo content >file && + git add file && + test_cmp expected actual +' + +test_expect_success 'with failing hook' ' + test_when_finished "rm -f actual" && + test_hook pre-add <<-\EOF && + echo pre-add-rejected >>actual + exit 1 + EOF + + echo content >file && + test_must_fail git add file +' + +test_expect_success '--no-verify with failing hook' ' + test_when_finished "rm -f actual" && + test_hook pre-add <<-\EOF && + echo should-not-run >>actual + exit 1 + EOF + + echo content >file && + git add --no-verify file && + test_path_is_missing actual +' + +test_expect_success 'setup for path-based tests' ' + git add file && + git commit -m "initial" +' + +test_expect_success 'hook found via core.hooksPath' ' + test_when_finished "git reset --hard && + rm -rf custom-hooks && + git config --unset core.hooksPath" && + mkdir custom-hooks && + write_script custom-hooks/pre-add <<-\EOF && + echo invoked >hook-ran + EOF + git config core.hooksPath custom-hooks && + echo changed >>file && + git add file && + test_path_is_file hook-ran && + rm -f hook-ran +' + +test_expect_success 'hook receives index-path and lockfile-path arguments' ' + test_when_finished "git reset --hard && + rm -f staged expect-count arg-count arg-one arg-two \ + expect-index expect-lockpath" && + echo staged >staged && + cat >expect-count <<-\EOF && + 2 + EOF + test_hook pre-add <<-\EOF && + echo "$#" >arg-count && + echo "$1" >arg-one && + echo "$2" >arg-two && + test "$1" != "$2" && + test -r "$2" + EOF + git add staged && + test_cmp expect-count arg-count && + printf "%s/index\n" "$(git rev-parse --absolute-git-dir)" >expect-index && + test_cmp expect-index arg-one && + sed "s/$/.lock/" expect-index >expect-lockpath && + test_cmp expect-lockpath arg-two +' + +test_expect_success 'hook rejection leaves final index unchanged' ' + test_when_finished "git reset --hard && rm -f reject index.before" && + cp .git/index index.before && + test_hook pre-add <<-\EOF && + exit 1 + EOF + echo reject >reject && + test_must_fail git add reject && + test_cmp_bin index.before .git/index && + test_path_is_missing .git/index.lock +' + +test_expect_success 'missing pre-existing index path treated as empty' ' + test_when_finished "git reset --hard && + rm -f newfile arg-one after.raw after expect-index" && + rm -f .git/index && + test_hook pre-add <<-\EOF && + echo "$1" >arg-one && + test ! -e "$1" && + GIT_INDEX_FILE="$2" git diff --cached --name-only HEAD >after.raw && + sort after.raw >after + EOF + echo newfile >newfile && + git add newfile && + printf "%s/index\n" "$(git rev-parse --absolute-git-dir)" >expect-index && + test_cmp expect-index arg-one && + grep "^newfile$" after && + grep "^file$" after +' + +test_expect_success 'hook respects GIT_INDEX_FILE' ' + test_when_finished "git reset --hard && + rm -f arg-one arg-two expect-index expect-lockpath \ + alt-index alt-index.lock" && + test_hook pre-add <<-\EOF && + echo "$1" >arg-one && + echo "$2" >arg-two + EOF + echo changed >>file && + GIT_INDEX_FILE=alt-index git add file && + test-tool path-utils absolute_path alt-index >expect-index && + test_cmp expect-index arg-one && + test-tool path-utils absolute_path alt-index.lock >expect-lockpath && + test_cmp expect-lockpath arg-two +' + +test_expect_success 'setup for mixed-result tests' ' + echo "*.ignored" >.gitignore && + git add .gitignore && + git commit -m "add gitignore" +' + +test_expect_success 'mixed-result add invokes pre-add hook' ' + test_when_finished "git reset --hard && + rm -f bad.ignored index.before hook-ran proposed" && + echo changed >>file && + echo ignored >bad.ignored && + cp .git/index index.before && + test_hook pre-add <<-\EOF && + GIT_INDEX_FILE="$2" git diff --cached --name-only HEAD >proposed && + grep "^file$" proposed && + echo invoked >hook-ran && + exit 1 + EOF + test_must_fail git add file bad.ignored && + test_path_is_file hook-ran && + test_cmp_bin index.before .git/index && + test_path_is_missing .git/index.lock +' + +test_expect_success 'mixed-result add stages tracked update on approve' ' + test_when_finished "git reset --hard && + rm -f bad.ignored hook-ran staged proposed" && + echo changed >>file && + echo ignored >bad.ignored && + test_hook pre-add <<-\EOF && + GIT_INDEX_FILE="$2" git diff --cached --name-only HEAD >proposed && + grep "^file$" proposed && + echo invoked >hook-ran + EOF + test_must_fail git add file bad.ignored && + test_path_is_file hook-ran && + git diff --cached --name-only HEAD >staged && + grep "^file$" staged && + test_path_is_missing .git/index.lock +' + +test_expect_success 'post-index-change fires after pre-add approval' ' + test_when_finished "git reset --hard && + rm -f hook-order expect lockfile-present" && + test_hook pre-add <<-\EOF && + echo pre >>hook-order + EOF + test_hook post-index-change <<-\EOF && + if test -f ".git/index.lock" + then + echo locked >lockfile-present + fi + echo post >>hook-order + EOF + echo updated >>file && + git add file && + cat >expect <<-\EOF && + pre + post + EOF + test_cmp expect hook-order && + test_path_is_missing lockfile-present +' + +test_expect_success 'post-index-change is suppressed on pre-add rejection' ' + test_when_finished "git reset --hard && + rm -f index.before hook-order expect" && + cp .git/index index.before && + test_hook pre-add <<-\EOF && + echo pre >>hook-order && + exit 1 + EOF + test_hook post-index-change <<-\EOF && + echo post >>hook-order + EOF + echo reject >>file && + test_must_fail git add file && + echo pre >expect && + test_cmp expect hook-order && + test_cmp_bin index.before .git/index && + test_path_is_missing .git/index.lock +' + +test_expect_success '--dry-run does not invoke hook' ' + test_when_finished "rm -f hook-ran dry" && + test_hook pre-add <<-\EOF && + echo invoked >hook-ran + EOF + echo dry >dry && + git add --dry-run dry && + test_path_is_missing hook-ran +' + +test_expect_success 'hook runs for git add -u' ' + test_when_finished "git reset --hard && rm -f hook-ran" && + test_hook pre-add <<-\EOF && + echo invoked >hook-ran + EOF + echo changed >>file && + git add -u && + test_path_is_file hook-ran +' + +test_expect_success 'hook example: block .env files' ' + test_when_finished "git reset --hard && + rm -f .env safe.txt new-paths" && + test_hook pre-add <<-\EOF && + GIT_INDEX_FILE="$2" git diff --cached --name-only HEAD >new-paths && + while read path + do + case "$path" in + *.env) + echo "error: $path must not be staged" >&2 + exit 1 + ;; + esac + done <new-paths + EOF + echo "DB_PASS=secret" >.env && + test_must_fail git add .env && + echo "safe content" >safe.txt && + git add safe.txt +' + +test_expect_success 'hook example: block secrets in content' ' + test_when_finished "git reset --hard && rm -f config.txt secret" && + test_hook pre-add <<-\EOF && + GIT_INDEX_FILE="$2" git diff --cached HEAD >secret && + if grep -q "API_KEY=" secret || + grep -q "SECRET_KEY=" secret || + grep -q "PRIVATE_KEY=" secret + then + echo "error: staged content contains secrets" >&2 + exit 1 + fi + EOF + echo "API_KEY=sksksk-live-12345" >config.txt && + test_must_fail git add config.txt && + echo "LOG_LEVEL=debug" >config.txt && + git add config.txt +' + +test_done base-commit: 7c02d39fc2ed2702223c7674f73150d9a7e61ba4
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