Merge branch 'ab/config-based-hooks-base' into seen

Restructuring of (a subset of) Emily's config-based-hooks series,
to demonstrate that a series can be presented as a more logical and
focused progression.

* ab/config-based-hooks-base: (30 commits)
  hook-list.h: add a generated list of hooks, like config-list.h
  hooks: fix a TOCTOU in "did we run a hook?" heuristic
  receive-pack: convert receive hooks to hook.h
  post-update: use hook.h library
  receive-pack: convert 'update' hook to hook.h
  hooks: allow callers to capture output
  run-command: allow capturing of collated output
  reference-transaction: use hook.h to run hooks
  transport: convert pre-push hook to use config
  hook: convert 'post-rewrite' hook in sequencer.c to hook.h
  hook: provide stdin by string_list or callback
  run-command: add stdin callback for parallelization
  am: convert 'post-rewrite' hook to hook.h
  hook: support passing stdin to hooks
  run-command: allow stdin for run_processes_parallel
  run-command: remove old run_hook_{le,ve}() hook API
  receive-pack: convert push-to-checkout hook to hook.h
  read-cache: convert post-index-change hook to use config
  commit: use hook.h to execute hooks
  git-p4: use 'git hook' to run hooks
  ...

Author: gitster

.gitignore

@@ -78,6 +78,7 @@
 /git-grep
 /git-hash-object
 /git-help
+/git-hook
 /git-http-backend
 /git-http-fetch
 /git-http-push
@@ -191,6 +192,7 @@
 /gitweb/static/gitweb.min.*
 /config-list.h
 /command-list.h
+/hook-list.h
 *.tar.gz
 *.dsc
 *.deb

Documentation/git-hook.txt

@@ -0,0 +1,49 @@
+git-hook(1)
+===========
+
+NAME
+----
+git-hook - run git hooks
+
+SYNOPSIS
+--------
+[verse]
+'git hook' run [--to-stdin=<path>] [--ignore-missing] <hook-name> [-- <hook-args>]
+
+DESCRIPTION
+-----------
+
+This command is an interface to git hooks (see linkgit:githooks[5]).
+Currently it only provides a convenience wrapper for running hooks for
+use by git itself. In the future it might gain other functionality.
+
+SUBCOMMANDS
+-----------
+
+run::
+
+	Run the `<hook-name>` hook. Any positional arguments to the
+	hook should be passed after an optional "--" (or
+	"--end-of-options"). See "OPTIONS" below for the arguments
+	this accepts.
+
+OPTIONS
+-------
+
+--to-stdin::
+	For "run"; Specify a file which will be streamed into the
+	hook's stdin. The hook will receive the entire file from
+	beginning to EOF.
+
+--ignore-missing::
+	Ignore any missing hook by quietly returning zero. Used for
+	tools that want to do a blind one-shot run of a hook that may
+	or may not be present.
+
+SEE ALSO
+--------
+linkgit:githooks[5]
+
+GIT
+---
+Part of the linkgit:git[1] suite

Documentation/githooks.txt

@@ -699,6 +699,10 @@ and "0" meaning they were not.
 Only one parameter should be set to "1" when the hook runs.  The hook
 running passing "1", "1" should not be possible.
 
+SEE ALSO
+--------
+linkgit:git-hook[1]
+
 GIT
 ---
 Part of the linkgit:git[1] suite

Makefile

@@ -830,6 +830,7 @@ XDIFF_LIB = xdiff/lib.a
 
 GENERATED_H += command-list.h
 GENERATED_H += config-list.h
+GENERATED_H += hook-list.h
 
 LIB_H := $(sort $(patsubst ./%,%,$(shell git ls-files '*.h' ':!t/' ':!Documentation/' 2>/dev/null || \
 	$(FIND) . \
@@ -915,6 +916,7 @@ LIB_OBJS += hash-lookup.o
 LIB_OBJS += hashmap.o
 LIB_OBJS += help.o
 LIB_OBJS += hex.o
+LIB_OBJS += hook.o
 LIB_OBJS += ident.o
 LIB_OBJS += json-writer.o
 LIB_OBJS += kwset.o
@@ -1116,6 +1118,7 @@ BUILTIN_OBJS += builtin/get-tar-commit-id.o
 BUILTIN_OBJS += builtin/grep.o
 BUILTIN_OBJS += builtin/hash-object.o
 BUILTIN_OBJS += builtin/help.o
+BUILTIN_OBJS += builtin/hook.o
 BUILTIN_OBJS += builtin/index-pack.o
 BUILTIN_OBJS += builtin/init-db.o
 BUILTIN_OBJS += builtin/interpret-trailers.o
@@ -2230,7 +2233,9 @@ git$X: git.o GIT-LDFLAGS $(BUILTIN_OBJS) $(GITLIBS)
 
 help.sp help.s help.o: command-list.h
 
-builtin/help.sp builtin/help.s builtin/help.o: config-list.h GIT-PREFIX
+hook.sp hook.s hook.o: hook-list.h
+
+builtin/help.sp builtin/help.s builtin/help.o: config-list.h hook-list.h GIT-PREFIX
 builtin/help.sp builtin/help.s builtin/help.o: EXTRA_CPPFLAGS = \
 	'-DGIT_HTML_PATH="$(htmldir_relative_SQ)"' \
 	'-DGIT_MAN_PATH="$(mandir_relative_SQ)"' \
@@ -2263,6 +2268,11 @@ command-list.h: $(wildcard Documentation/git*.txt)
 		$(patsubst %,--exclude-program %,$(EXCLUDED_PROGRAMS)) \
 		command-list.txt >$@+ && mv $@+ $@
 
+hook-list.h: generate-hooklist.sh
+hook-list.h: Documentation/githooks.txt
+	$(QUIET_GEN)$(SHELL_PATH) ./generate-hooklist.sh \
+		>$@+ && mv $@+ $@
+
 SCRIPT_DEFINES = $(SHELL_PATH_SQ):$(DIFF_SQ):$(GIT_VERSION):\
 	$(localedir_SQ):$(NO_CURL):$(USE_GETTEXT_SCHEME):$(SANE_TOOL_PATH_SQ):\
 	$(gitwebdir_SQ):$(PERL_PATH_SQ):$(SANE_TEXT_GREP):$(PAGER_ENV):\
@@ -2919,7 +2929,7 @@ $(SP_OBJ): %.sp: %.c GIT-CFLAGS FORCE
 .PHONY: sparse $(SP_OBJ)
 sparse: $(SP_OBJ)
 
-EXCEPT_HDRS := command-list.h config-list.h unicode-width.h compat/% xdiff/%
+EXCEPT_HDRS := command-list.h config-list.h hook-list.h unicode-width.h compat/% xdiff/%
 ifndef GCRYPT_SHA256
 	EXCEPT_HDRS += sha256/gcrypt.h
 endif
@@ -2941,7 +2951,7 @@ hdr-check: $(HCO)
 style:
 	git clang-format --style file --diff --extensions c,h
 
-check: config-list.h command-list.h
+check: config-list.h command-list.h hook-list.h
 	@if sparse; \
 	then \
 		echo >&2 "Use 'make sparse' instead"; \

builtin.h

@@ -165,6 +165,7 @@ int cmd_get_tar_commit_id(int argc, const char **argv, const char *prefix);
 int cmd_grep(int argc, const char **argv, const char *prefix);
 int cmd_hash_object(int argc, const char **argv, const char *prefix);
 int cmd_help(int argc, const char **argv, const char *prefix);
+int cmd_hook(int argc, const char **argv, const char *prefix);
 int cmd_index_pack(int argc, const char **argv, const char *prefix);
 int cmd_init_db(int argc, const char **argv, const char *prefix);
 int cmd_interpret_trailers(int argc, const char **argv, const char *prefix);

builtin/am.c

@@ -11,6 +11,7 @@
 #include "parse-options.h"
 #include "dir.h"
 #include "run-command.h"
+#include "hook.h"
 #include "quote.h"
 #include "tempfile.h"
 #include "lockfile.h"
@@ -444,9 +445,12 @@ static void am_destroy(const struct am_state *state)
 static int run_applypatch_msg_hook(struct am_state *state)
 {
 	int ret;
+	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
 
 	assert(state->msg);
-	ret = run_hook_le(NULL, "applypatch-msg", am_path(state, "final-commit"), NULL);
+	strvec_push(&opt.args, am_path(state, "final-commit"));
+	ret = run_hooks("applypatch-msg", &opt);
+	run_hooks_opt_clear(&opt);
 
 	if (!ret) {
 		FREE_AND_NULL(state->msg);
@@ -463,23 +467,15 @@ static int run_applypatch_msg_hook(struct am_state *state)
  */
 static int run_post_rewrite_hook(const struct am_state *state)
 {
-	struct child_process cp = CHILD_PROCESS_INIT;
-	const char *hook = find_hook("post-rewrite");
+	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
 	int ret;
 
-	if (!hook)
-		return 0;
-
-	strvec_push(&cp.args, hook);
-	strvec_push(&cp.args, "rebase");
+	strvec_push(&opt.args, "rebase");
+	opt.path_to_stdin = am_path(state, "rewritten");
 
-	cp.in = xopen(am_path(state, "rewritten"), O_RDONLY);
-	cp.stdout_to_stderr = 1;
-	cp.trace2_hook_name = "post-rewrite";
+	ret = run_hooks("post-rewrite", &opt);
 
-	ret = run_command(&cp);
-
-	close(cp.in);
+	run_hooks_opt_clear(&opt);
 	return ret;
 }
 
@@ -1606,9 +1602,13 @@ static void do_commit(const struct am_state *state)
 	struct commit_list *parents = NULL;
 	const char *reflog_msg, *author, *committer = NULL;
 	struct strbuf sb = STRBUF_INIT;
+	struct run_hooks_opt hook_opt_pre = RUN_HOOKS_OPT_INIT;
+	struct run_hooks_opt hook_opt_post = RUN_HOOKS_OPT_INIT;
 
-	if (run_hook_le(NULL, "pre-applypatch", NULL))
+	if (run_hooks("pre-applypatch", &hook_opt_pre)) {
+		run_hooks_opt_clear(&hook_opt_pre);
 		exit(1);
+	}
 
 	if (write_cache_as_tree(&tree, 0, NULL))
 		die(_("git write-tree failed to write a tree"));
@@ -1659,8 +1659,10 @@ static void do_commit(const struct am_state *state)
 		fclose(fp);
 	}
 
-	run_hook_le(NULL, "post-applypatch", NULL);
+	run_hooks("post-applypatch", &hook_opt_post);
 
+	run_hooks_opt_clear(&hook_opt_pre);
+	run_hooks_opt_clear(&hook_opt_post);
 	strbuf_release(&sb);
 }
 

builtin/bugreport.c

@@ -3,7 +3,8 @@
 #include "strbuf.h"
 #include "help.h"
 #include "compat/compiler.h"
-#include "run-command.h"
+#include "hook.h"
+#include "hook-list.h"
 
 
 static void get_system_info(struct strbuf *sys_info)
@@ -41,49 +42,20 @@ static void get_system_info(struct strbuf *sys_info)
 
 static void get_populated_hooks(struct strbuf *hook_info, int nongit)
 {
-	/*
-	 * NEEDSWORK: Doesn't look like there is a list of all possible hooks;
-	 * so below is a transcription of `git help hooks`. Later, this should
-	 * be replaced with some programmatically generated list (generated from
-	 * doc or else taken from some library which tells us about all the
-	 * hooks)
-	 */
-	static const char *hook[] = {
-		"applypatch-msg",
-		"pre-applypatch",
-		"post-applypatch",
-		"pre-commit",
-		"pre-merge-commit",
-		"prepare-commit-msg",
-		"commit-msg",
-		"post-commit",
-		"pre-rebase",
-		"post-checkout",
-		"post-merge",
-		"pre-push",
-		"pre-receive",
-		"update",
-		"post-receive",
-		"post-update",
-		"push-to-checkout",
-		"pre-auto-gc",
-		"post-rewrite",
-		"sendemail-validate",
-		"fsmonitor-watchman",
-		"p4-pre-submit",
-		"post-index-change",
-	};
-	int i;
+	const char **p;
 
 	if (nongit) {
 		strbuf_addstr(hook_info,
 			_("not run from a git repository - no hooks to show\n"));
 		return;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(hook); i++)
-		if (find_hook(hook[i]))
-			strbuf_addf(hook_info, "%s\n", hook[i]);
+	for (p = hook_name_list; *p; p++) {
+		const char *hook = *p;
+
+		if (hook_exists(hook))
+			strbuf_addf(hook_info, "%s\n", hook);
+	}
 }
 
 static const char * const bugreport_usage[] = {

builtin/checkout.c

@@ -9,6 +9,7 @@
 #include "config.h"
 #include "diff.h"
 #include "dir.h"
+#include "hook.h"
 #include "ll-merge.h"
 #include "lockfile.h"
 #include "merge-recursive.h"
@@ -106,13 +107,19 @@ struct branch_info {
 static int post_checkout_hook(struct commit *old_commit, struct commit *new_commit,
 			      int changed)
 {
-	return run_hook_le(NULL, "post-checkout",
-			   oid_to_hex(old_commit ? &old_commit->object.oid : null_oid()),
-			   oid_to_hex(new_commit ? &new_commit->object.oid : null_oid()),
-			   changed ? "1" : "0", NULL);
+	struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
+	int rc;
+
 	/* "new_commit" can be NULL when checking out from the index before
 	   a commit exists. */
-
+	strvec_pushl(&opt.args,
+		     oid_to_hex(old_commit ? &old_commit->object.oid : null_oid()),
+		     oid_to_hex(new_commit ? &new_commit->object.oid : null_oid()),
+		     changed ? "1" : "0",
+		     NULL);
+	rc = run_hooks("post-checkout", &opt);
+	run_hooks_opt_clear(&opt);
+	return rc;
 }
 
 static int update_some(const struct object_id *oid, struct strbuf *base,

builtin/clone.c

@@ -32,6 +32,7 @@
 #include "connected.h"
 #include "packfile.h"
 #include "list-objects-filter-options.h"
+#include "hook.h"
 
 /*
  * Overall FIXMEs:
@@ -775,6 +776,7 @@ static int checkout(int submodule_progress)
 	struct tree *tree;
 	struct tree_desc t;
 	int err = 0;
+	struct run_hooks_opt hook_opt = RUN_HOOKS_OPT_INIT;
 
 	if (option_no_checkout)
 		return 0;
@@ -820,8 +822,9 @@ static int checkout(int submodule_progress)
 	if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
 		die(_("unable to write new index file"));
 
-	err |= run_hook_le(NULL, "post-checkout", oid_to_hex(null_oid()),
-			   oid_to_hex(&oid), "1", NULL);
+	strvec_pushl(&hook_opt.args, oid_to_hex(null_oid()), oid_to_hex(&oid), "1", NULL);
+	err |= run_hooks("post-checkout", &hook_opt);
+	run_hooks_opt_clear(&hook_opt);
 
 	if (!err && (option_recurse_submodules.nr > 0)) {
 		struct strvec args = STRVEC_INIT;