[PATCH v7 11/15] bugreport: collect list of populated hooks

[Emily Shaffer <emilyshaffer@google.com>]

Occasionally a failure a user is seeing may be related to a specific
hook which is being run, perhaps without the user realizing. While the
contents of hooks can be sensitive - containing user data or process
information specific to the user's organization - simply knowing that a
hook is being run at a certain stage can help us to understand whether
something is going wrong.

Without a definitive list of hook names within the code, we compile our
own list from the documentation. This is likely prone to bitrot. To
reduce the amount of code humans need to read, we turn the list into a
string_list and iterate over it (as we are calling the same find_hook
operation on each string). However, since bugreport should primarily be
called by the user, the performance loss from massaging the string
seems acceptable.

Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
---
 Documentation/git-bugreport.txt |  1 +
 bugreport.c                     | 53 +++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+)

diff --git a/Documentation/git-bugreport.txt b/Documentation/git-bugreport.txt
index 4e9171d1bd..779c9c7fd9 100644
--- a/Documentation/git-bugreport.txt
+++ b/Documentation/git-bugreport.txt
@@ -31,6 +31,7 @@ The following information is captured automatically:
  - 'git remote-https --build-info'
  - $SHELL
  - Selected config values
+ - A list of enabled hooks
 
 OPTIONS
 -------
diff --git a/bugreport.c b/bugreport.c
index 1a9430a857..7e6147a935 100644
--- a/bugreport.c
+++ b/bugreport.c
@@ -9,6 +9,7 @@
 #include "config.h"
 #include "bugreport-config-safelist.h"
 #include "khash.h"
+#include "run-command.h"
 
 static void get_git_remote_https_version_info(struct strbuf *version_info)
 {
@@ -78,6 +79,55 @@ static void get_safelisted_config(struct strbuf *config_info)
 	}
 }
 
+static void get_populated_hooks(struct strbuf *hook_info, int nongit)
+{
+	/*
+	 * Doesn't look like there is a list of all possible hooks; so below is
+	 * a transcription of `git help hooks`.
+	 */
+	const char *hooks = "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-changex";
+	struct string_list hooks_list = STRING_LIST_INIT_DUP;
+	struct string_list_item *iter = NULL;
+
+
+	if (nongit) {
+		strbuf_addstr(hook_info,
+			"not run from a git repository - no hooks to show\n");
+		return;
+	}
+
+	string_list_split(&hooks_list, hooks, ',', -1);
+
+	for_each_string_list_item(iter, &hooks_list) {
+		if (find_hook(iter->string)) {
+			strbuf_addstr(hook_info, iter->string);
+			strbuf_complete_line(hook_info);
+		}
+	}
+}
+
 static const char * const bugreport_usage[] = {
 	N_("git bugreport [-o|--output-directory <file>] [-s|--suffix <format>]"),
 	NULL
@@ -166,6 +216,9 @@ int cmd_main(int argc, const char **argv)
 	get_header(&buffer, "Safelisted Config Info");
 	get_safelisted_config(&buffer);
 
+	get_header(&buffer, "Enabled Hooks");
+	get_populated_hooks(&buffer, nongit_ok);
+
 	report = fopen_for_writing(report_path.buf);
 
 	if (report == NULL) {
-- 
2.25.0.265.gbab2e86ba0-goog