[PATCH v3 5/9] 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>
---
 bugreport.c         | 44 ++++++++++++++++++++++++++++++++++++++++++++
 bugreport.h         |  6 ++++++
 builtin/bugreport.c |  4 ++++
 3 files changed, 54 insertions(+)

diff --git a/bugreport.c b/bugreport.c
index afa4836ab1..9d7f44ff28 100644
--- a/bugreport.c
+++ b/bugreport.c
@@ -103,3 +103,47 @@ void get_whitelisted_config(struct strbuf *config_info)
 	strbuf_reset(config_info);
 	strbuf_addbuf(config_info, &configs_and_values);
 }
+
+void get_populated_hooks(struct strbuf *hook_info)
+{
+	/*
+	 * Doesn't look like there is a list of all possible hooks; so below is
+	 * a transcription of `git help hook`.
+	 */
+	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;
+
+	strbuf_reset(hook_info);
+
+	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);
+		}
+	}
+}
diff --git a/bugreport.h b/bugreport.h
index 7413e7e1be..942a5436e3 100644
--- a/bugreport.h
+++ b/bugreport.h
@@ -12,3 +12,9 @@ void get_system_info(struct strbuf *sys_info);
  * config_info will be discarded.
  */
 void get_whitelisted_config(struct strbuf *sys_info);
+
+/**
+ * Adds the paths to all configured hooks (but not their contents). The previous
+ * contents of hook_info will be discarded.
+ */
+void get_populated_hooks(struct strbuf *hook_info);
diff --git a/builtin/bugreport.c b/builtin/bugreport.c
index 70fe0d2b85..a0eefba498 100644
--- a/builtin/bugreport.c
+++ b/builtin/bugreport.c
@@ -60,6 +60,10 @@ int cmd_bugreport(int argc, const char **argv, const char *prefix)
 	get_whitelisted_config(&buffer);
 	strbuf_write(&buffer, report);
 
+	add_header(report, "Populated Hooks");
+	get_populated_hooks(&buffer);
+	strbuf_write(&buffer, report);
+
 	fclose(report);
 
 	launch_editor(report_path.buf, NULL, NULL);
-- 
2.24.0.rc0.303.g954a862665-goog