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[PATCH v2 1/8] hook: add internal state alloc/free callbacks

From
Adrian Ratiu <adrian.ratiu@collabora.com>
Date
Feb 18, 2026, 22:23 UTC
Message-ID
<20260218222352.55393-2-adrian.ratiu@collabora.com>
In-Reply-To
<20260218222352.55393-1-adrian.ratiu@collabora.com>
Some hooks use opaque structs to keep internal state between callbacks.

Because hooks ran sequentially (jobs == 1) with one command per hook, these internal states could be allocated on the stack for each hook run.

Next commits add the ability to run multiple commands for each hook, so the states cannot be shared or stored on the stack anymore, especially since down the line we will also enable parallel execution (jobs > 1).

Add alloc/free helpers for each hook, doing a "deep" alloc/init & free of their internal opaque struct.

The alloc callback takes a context pointer, to initialize the struct at at the time of resource acquisition.

These callbacks must always be provided together: no alloc without free and no free without alloc, otherwise a BUG() is triggered.

Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
---
 builtin/receive-pack.c | 33 ++++++++++++++++++++++++++-------
 hook.c                 | 13 +++++++++++++
 hook.h                 | 25 ++++++++++++++++++++++++-
 refs.c                 | 24 +++++++++++++++++++-----
 transport.c            | 27 ++++++++++++++++++++-------
 5 files changed, 102 insertions(+), 20 deletions(-)
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 2d2b33d73d..f23772bc56 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -901,6 +901,26 @@ static int feed_receive_hook_cb(int hook_stdin_fd, void *pp_cb UNUSED, void *pp_
 	return state->cmd ? 0 : 1;  /* 0 = more to come, 1 = EOF */
 }
 
+static void *receive_hook_feed_state_alloc(void *feed_pipe_ctx)
+{
+	struct receive_hook_feed_state *init_state = feed_pipe_ctx;
+	struct receive_hook_feed_state *data = xcalloc(1, sizeof(*data));
+	data->report = init_state->report;
+	data->cmd = init_state->cmd;
+	data->skip_broken = init_state->skip_broken;
+	strbuf_init(&data->buf, 0);
+	return data;
+}
+
+static void receive_hook_feed_state_free(void *data)
+{
+	struct receive_hook_feed_state *d = data;
+	if (!d)
+		return;
+	strbuf_release(&d->buf);
+	free(d);
+}
+
 static int run_receive_hook(struct command *commands,
 			    const char *hook_name,
 			    int skip_broken,
@@ -908,7 +928,7 @@ static int run_receive_hook(struct command *commands,
 {
 	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
 	struct command *iter = commands;
-	struct receive_hook_feed_state feed_state;
+	struct receive_hook_feed_state feed_init_state = { 0 };
 	struct async sideband_async;
 	int sideband_async_started = 0;
 	int saved_stderr = -1;
@@ -938,16 +958,15 @@ static int run_receive_hook(struct command *commands,
 	prepare_sideband_async(&sideband_async, &saved_stderr, &sideband_async_started);
 
 	/* set up stdin callback */
-	feed_state.cmd = commands;
-	feed_state.skip_broken = skip_broken;
-	feed_state.report = NULL;
-	strbuf_init(&feed_state.buf, 0);
-	opt.feed_pipe_cb_data = &feed_state;
+	feed_init_state.cmd = commands;
+	feed_init_state.skip_broken = skip_broken;
+	opt.feed_pipe_ctx = &feed_init_state;
 	opt.feed_pipe = feed_receive_hook_cb;
+	opt.feed_pipe_cb_data_alloc = receive_hook_feed_state_alloc;
+	opt.feed_pipe_cb_data_free = receive_hook_feed_state_free;
 
 	ret = run_hooks_opt(the_repository, hook_name, &opt);
 
-	strbuf_release(&feed_state.buf);
 	finish_sideband_async(&sideband_async, saved_stderr, sideband_async_started);
 
 	return ret;
diff --git a/hook.c b/hook.c
index cde7198412..83ff658866 100644
--- a/hook.c
+++ b/hook.c
@@ -133,6 +133,8 @@ static int notify_hook_finished(int result,
 
 static void run_hooks_opt_clear(struct run_hooks_opt *options)
 {
+	if (options->feed_pipe_cb_data_free)
+		options->feed_pipe_cb_data_free(options->feed_pipe_cb_data);
 	strvec_clear(&options->env);
 	strvec_clear(&options->args);
 }
@@ -172,6 +174,17 @@ int run_hooks_opt(struct repository *r, const char *hook_name,
 	if (!options->jobs)
 		BUG("run_hooks_opt must be called with options.jobs >= 1");
 
+	/*
+	 * Ensure cb_data copy and free functions are either provided together,
+	 * or neither one is provided.
+	 */
+	if ((options->feed_pipe_cb_data_alloc && !options->feed_pipe_cb_data_free) ||
+	    (!options->feed_pipe_cb_data_alloc && options->feed_pipe_cb_data_free))
+		BUG("feed_pipe_cb_data_alloc and feed_pipe_cb_data_free must be set together");
+
+	if (options->feed_pipe_cb_data_alloc)
+		options->feed_pipe_cb_data = options->feed_pipe_cb_data_alloc(options->feed_pipe_ctx);
+
 	if (options->invoked_hook)
 		*options->invoked_hook = 0;
 
diff --git a/hook.h b/hook.h
index 20eb56fd63..a6bdc6f90f 100644
--- a/hook.h
+++ b/hook.h
@@ -5,6 +5,9 @@
 
 struct repository;
 
+typedef void (*cb_data_free_fn)(void *data);
+typedef void *(*cb_data_alloc_fn)(void *init_ctx);
+
 struct run_hooks_opt
 {
 	/* Environment vars to be set for each hook */
@@ -88,10 +91,30 @@ struct run_hooks_opt
 	 * It can be accessed directly via the third callback arg 'pp_task_cb':
 	 * struct ... *state = pp_task_cb;
 	 *
-	 * The caller is responsible for managing the memory for this data.
+	 * The caller is responsible for managing the memory for this data by
+	 * providing alloc/free callbacks to `run_hooks_opt`.
+	 *
 	 * Only useful when using `run_hooks_opt.feed_pipe`, otherwise ignore it.
 	 */
 	void *feed_pipe_cb_data;
+
+	/**
+	 * Some hooks need to create a fresh `feed_pipe_cb_data` internal state,
+	 * so they can keep track of progress without affecting one another.
+	 *
+	 * If provided, this function will be called to alloc & initialize the
+	 * `feed_pipe_cb_data` for each hook.
+	 *
+	 * The `feed_pipe_ctx` pointer can be used to pass initialization data.
+	 */
+	cb_data_alloc_fn feed_pipe_cb_data_alloc;
+
+	/**
+	 * Called to free the memory initialized by `feed_pipe_cb_data_alloc`.
+	 *
+	 * Must always be provided when `feed_pipe_cb_data_alloc` is provided.
+	 */
+	cb_data_free_fn feed_pipe_cb_data_free;
 };
 
 #define RUN_HOOKS_OPT_INIT { \
diff --git a/refs.c b/refs.c
index d432cfb78f..3c124fab29 100644
--- a/refs.c
+++ b/refs.c
@@ -2514,24 +2514,38 @@ static int transaction_hook_feed_stdin(int hook_stdin_fd, void *pp_cb, void *pp_
 	return 0; /* no more input to feed */
 }
 
+static void *transaction_feed_cb_data_alloc(void *feed_pipe_ctx UNUSED)
+{
+	struct transaction_feed_cb_data *data = xmalloc(sizeof(*data));
+	strbuf_init(&data->buf, 0);
+	data->index = 0;
+	return data;
+}
+
+static void transaction_feed_cb_data_free(void *data)
+{
+	struct transaction_feed_cb_data *d = data;
+	if (!d)
+		return;
+	strbuf_release(&d->buf);
+	free(d);
+}
+
 static int run_transaction_hook(struct ref_transaction *transaction,
 				const char *state)
 {
 	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
-	struct transaction_feed_cb_data feed_ctx = { 0 };
 	int ret = 0;
 
 	strvec_push(&opt.args, state);
 
 	opt.feed_pipe = transaction_hook_feed_stdin;
 	opt.feed_pipe_ctx = transaction;
-	opt.feed_pipe_cb_data = &feed_ctx;
-
-	strbuf_init(&feed_ctx.buf, 0);
+	opt.feed_pipe_cb_data_alloc = transaction_feed_cb_data_alloc;
+	opt.feed_pipe_cb_data_free = transaction_feed_cb_data_free;
 
 	ret = run_hooks_opt(transaction->ref_store->repo, "reference-transaction", &opt);
 
-	strbuf_release(&feed_ctx.buf);
 	return ret;
 }
 
diff --git a/transport.c b/transport.c
index ecf9e1f21c..1581aa0886 100644
--- a/transport.c
+++ b/transport.c
@@ -1357,21 +1357,36 @@ static int pre_push_hook_feed_stdin(int hook_stdin_fd, void *pp_cb UNUSED, void
 	return 0;
 }
 
+static void *pre_push_hook_data_alloc(void *feed_pipe_ctx)
+{
+	struct feed_pre_push_hook_data *data = xmalloc(sizeof(*data));
+	strbuf_init(&data->buf, 0);
+	data->refs = (struct ref *)feed_pipe_ctx;
+	return data;
+}
+
+static void pre_push_hook_data_free(void *data)
+{
+	struct feed_pre_push_hook_data *d = data;
+	if (!d)
+		return;
+	strbuf_release(&d->buf);
+	free(d);
+}
+
 static int run_pre_push_hook(struct transport *transport,
 			     struct ref *remote_refs)
 {
 	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
-	struct feed_pre_push_hook_data data;
 	int ret = 0;
 
 	strvec_push(&opt.args, transport->remote->name);
 	strvec_push(&opt.args, transport->url);
 
-	strbuf_init(&data.buf, 0);
-	data.refs = remote_refs;
-
 	opt.feed_pipe = pre_push_hook_feed_stdin;
-	opt.feed_pipe_cb_data = &data;
+	opt.feed_pipe_ctx = remote_refs;
+	opt.feed_pipe_cb_data_alloc = pre_push_hook_data_alloc;
+	opt.feed_pipe_cb_data_free = pre_push_hook_data_free;
 
 	/*
 	 * pre-push hooks expect stdout & stderr to be separate, so don't merge
@@ -1381,8 +1396,6 @@ static int run_pre_push_hook(struct transport *transport,
 
 	ret = run_hooks_opt(the_repository, "pre-push", &opt);
 
-	strbuf_release(&data.buf);
-
 	return ret;
 }
 
-- 
2.52.0.732.gb351b5166d.dirty
Previous: Adrian RatiuNext: Junio C Hamano
Message 22 of 71 in “Specify hooks via configs”
  1. 0/4 Specify hooks via configsAdrian Ratiu, Feb 4, 2026
  2. 2/4 hook: introduce "git hook list"Adrian Ratiu, Feb 4, 2026
  3. Patrick SteinhardtFeb 9, 2026
  4. Adrian RatiuFeb 9, 2026
  5. 3/4 hook: include hooks from the configAdrian Ratiu, Feb 4, 2026
  6. Patrick SteinhardtFeb 9, 2026
  7. Adrian RatiuFeb 9, 2026
  8. Patrick SteinhardtFeb 10, 2026
  9. Adrian RatiuFeb 10, 2026
  10. 1/4 hook: run a list of hooksAdrian Ratiu, Feb 4, 2026
  11. Junio C HamanoFeb 5, 2026
  12. Adrian RatiuFeb 6, 2026
  13. Patrick SteinhardtFeb 9, 2026
  14. Adrian RatiuFeb 9, 2026
  15. Patrick SteinhardtFeb 10, 2026
  16. 4/4 hook: allow out-of-repo 'git hook' invocationsAdrian Ratiu, Feb 4, 2026
  17. Junio C HamanoFeb 6, 2026
  18. 0/8 Specify hooks via configsAdrian Ratiu, Feb 18, 2026
  19. 2/8 hook: run a list of hooks to prepare for multihook supportAdrian Ratiu, Feb 18, 2026
  20. Patrick SteinhardtFeb 20, 2026
  21. Adrian RatiuFeb 20, 2026
  22. 1/8 hook: add internal state alloc/free callbacksAdrian Ratiu, Feb 18, 2026
  23. Junio C HamanoFeb 19, 2026
  24. Adrian RatiuFeb 20, 2026
  25. Junio C HamanoFeb 20, 2026
  26. Adrian RatiuFeb 20, 2026
  27. Patrick SteinhardtFeb 20, 2026
  28. Adrian RatiuFeb 20, 2026
  29. 3/8 hook: add "git hook list" commandAdrian Ratiu, Feb 18, 2026
  30. Patrick SteinhardtFeb 20, 2026
  31. Adrian RatiuFeb 20, 2026
  32. 5/8 hook: allow disabling config hooksAdrian Ratiu, Feb 18, 2026
  33. Patrick SteinhardtFeb 20, 2026
  34. Adrian RatiuFeb 20, 2026
  35. Patrick SteinhardtFeb 20, 2026
  36. Junio C HamanoFeb 20, 2026
  37. 6/8 hook: allow event = "" to overwrite previous valuesAdrian Ratiu, Feb 18, 2026
  38. 4/8 hook: include hooks from the configAdrian Ratiu, Feb 18, 2026
  39. Junio C HamanoFeb 19, 2026
  40. Adrian RatiuFeb 20, 2026
  41. Patrick SteinhardtFeb 20, 2026
  42. Adrian RatiuFeb 20, 2026
  43. 7/8 hook: allow out-of-repo 'git hook' invocationsAdrian Ratiu, Feb 18, 2026
  44. 8/8 hook: add -z option to "git hook list"Adrian Ratiu, Feb 18, 2026
  45. Junio C HamanoFeb 19, 2026
  46. Adrian RatiuFeb 20, 2026
  47. brian m. carlsonFeb 20, 2026
  48. Adrian RatiuFeb 21, 2026
  49. Adrian RatiuFeb 22, 2026
  50. Junio C HamanoFeb 25, 2026
  51. Adrian RatiuFeb 26, 2026
  52. brian m. carlsonFeb 25, 2026
  53. Adrian RatiuFeb 26, 2026
  54. 00/12 [next] Specify hooks via configsAdrian Ratiu, Mar 1, 2026
  55. 02/12 hook: run a list of hooks to prepare for multihook supportAdrian Ratiu, Mar 1, 2026
  56. 03/12 hook: add "git hook list" commandAdrian Ratiu, Mar 1, 2026
  57. 01/12 hook: add internal state alloc/free callbacksAdrian Ratiu, Mar 1, 2026
  58. 04/12 string-list: add unsorted_string_list_remove()Adrian Ratiu, Mar 1, 2026
  59. 06/12 hook: allow disabling config hooksAdrian Ratiu, Mar 1, 2026
  60. 05/12 hook: include hooks from the configAdrian Ratiu, Mar 1, 2026
  61. SZEDER GáborApr 6, 2026
  62. Adrian RatiuApr 8, 2026
  63. 07/12 hook: allow event = "" to overwrite previous valuesAdrian Ratiu, Mar 1, 2026
  64. 08/12 hook: allow out-of-repo 'git hook' invocationsAdrian Ratiu, Mar 1, 2026
  65. 09/12 hook: add -z option to "git hook list"Adrian Ratiu, Mar 1, 2026
  66. 10/12 hook: refactor hook_config_cache from strmap to named structAdrian Ratiu, Mar 1, 2026
  67. 11/12 hook: store and display scope for configured hooks in git hook listAdrian Ratiu, Mar 1, 2026
  68. 12/12 hook: show disabled hooks in "git hook list"Adrian Ratiu, Mar 1, 2026
  69. Junio C HamanoMar 2, 2026
  70. Adrian RatiuMar 2, 2026
  71. Junio C HamanoMar 2, 2026

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