Re: [PATCH 31/31] hook-list.h: add a generated list of hooks, like config-list.h

Resolve a long-standing TODO item in bugreport.c of there being no
centralized listing of hooks, this fixes a bug with the bugreport
listing only knowing about 1/4 of the p4 hooks. It didn't know about
the "reference-transaction" hook either.

We can now make sure this is kept up-to-date, as the hook.c library
will die if asked to find a hook we don't know about yet. The only
(undocumented) exception is the artificial "test-hook" used in our own
test suite. Move some of the tests away from the "does-not-exist"
pseudo-hook, and test for the new behavior.

Signed-off-by: Ævar Arnfjörð Bjarmason <redacted>
---
 .gitignore           |  1 +
 Makefile             | 14 +++++++++++---
 builtin/bugreport.c  | 44 ++++++++------------------------------------
 generate-hooklist.sh | 20 ++++++++++++++++++++
 hook.c               | 22 ++++++++++++++++++++++
 t/t1800-hook.sh      | 14 +++++++++++---
 6 files changed, 73 insertions(+), 42 deletions(-)
 create mode 100755 generate-hooklist.sh

diff --git a/.gitignore b/.gitignore
index de39dc9961b..66189ca3cdc 100644
--- a/.gitignore
+++ b/.gitignore

@@ -191,6 +191,7 @@
 /gitweb/static/gitweb.min.*
 /config-list.h
 /command-list.h
+/hook-list.h
 *.tar.gz
 *.dsc
 *.deb

diff --git a/Makefile b/Makefile
index a6b71a0fbed..d0532f3c744 100644
--- a/Makefile
+++ b/Makefile

@@ -817,6 +817,7 @@ 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) . \

@@ -2207,7 +2208,9 @@ 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)"' \

@@ -2240,6 +2243,11 @@ 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):\

@@ -2890,7 +2898,7 @@ $(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

@@ -2912,7 +2920,7 @@ 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"; \

diff --git a/builtin/bugreport.c b/builtin/bugreport.c
index 941c8d5e270..a7a1fcb8a7a 100644
--- a/builtin/bugreport.c
+++ b/builtin/bugreport.c

@@ -4,6 +4,7 @@
 #include "help.h"
 #include "compat/compiler.h"
 #include "hook.h"
+#include "hook-list.h"
 
 
 static void get_system_info(struct strbuf *sys_info)

@@ -41,39 +42,7 @@ 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,

@@ -81,9 +50,12 @@ static void get_populated_hooks(struct strbuf *hook_info, int nongit)
 		return;
 	}
 
-	for (i = 0; i < ARRAY_SIZE(hook); i++)
-		if (hook_exists(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[] = {

diff --git a/generate-hooklist.sh b/generate-hooklist.sh
new file mode 100755
index 00000000000..25a7207b276
--- /dev/null
+++ b/generate-hooklist.sh

@@ -0,0 +1,20 @@
+#!/bin/sh
+
+echo "/* Automatically generated by generate-hooklist.sh */"
+
+print_hook_list () {
+	cat <<EOF
+static const char *hook_name_list[] = {
+EOF
+	grep -C1 -h '^~~~' Documentation/githooks.txt |
+	grep '^[a-z0-9][a-z0-9-]*$' |
+	sort |
+	sed 's/^.*$/	"&",/'
+	cat <<EOF
+	NULL,
+};
+EOF
+}
+