Subject: [PATCH v2 4/5] receive-pack: read env from proc-receive output

From: Jiang Xin <[email-masked]>
Date: Sun, 8 Mar 2020 11:38:15 -0400

From: Jiang Xin <[email-masked]>

The “post-receive” hook may need the pull request ID generated by the
“proc-receive” hook.  The results can be passed between hooks by
environment variables.

Each line of the message received from the standard output of the
“proc-receive” hook in the key=value format is parsed as environment and
these variables will be sent to environment of the “post-receive” hook.

Signed-off-by: Jiang Xin <[email-masked]>
---
 builtin/receive-pack.c       | 38 ++++++++++++++++++--
 t/t5411-proc-receive-hook.sh | 70 ++++++++++++++++++++++++++++++++++++
 2 files changed, 105 insertions(+), 3 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 5aff682758..d854952410 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -87,6 +87,7 @@ static const char *nonce_status;
 static long nonce_stamp_slop;
 static timestamp_t nonce_stamp_slop_limit;
 static struct ref_transaction *transaction;
+struct argv_array post_receive_env_array;
 
 static enum {
 	KEEPALIVE_NEVER = 0,
@@ -694,7 +695,9 @@ struct receive_hook_feed_state {
 };
 
 typedef int (*feed_fn)(void *, const char **, size_t *);
+typedef void (*stdout_handler_fn)(int out);
 static int run_and_feed_hook(const char *hook_name, feed_fn feed,
+			     stdout_handler_fn stdout_handler,
 			     struct receive_hook_feed_state *feed_state)
 {
 	struct child_process proc = CHILD_PROCESS_INIT;
@@ -716,9 +719,15 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed,
 
 	proc.argv = argv;
 	proc.in = -1;
-	proc.stdout_to_stderr = 1;
+	if (stdout_handler)
+		proc.out = -1;
+	else
+		proc.stdout_to_stderr = 1;
 	proc.trace2_hook_name = hook_name;
 
+	if (!strcmp(hook_name, "post-receive") && post_receive_env_array.argc > 0)
+		argv_array_pushv(&proc.env_array, post_receive_env_array.argv);
+
 	if (feed_state->push_options) {
 		int i;
 		for (i = 0; i < feed_state->push_options->nr; i++)
@@ -763,6 +772,10 @@ static int run_and_feed_hook(const char *hook_name, feed_fn feed,
 			break;
 	}
 	close(proc.in);
+
+	if (stdout_handler)
+		stdout_handler(proc.out);
+
 	if (use_sideband)
 		finish_async(&muxer);
 
@@ -819,7 +832,7 @@ static int run_receive_hook(struct command *commands,
 		return 0;
 	state.cmd = commands;
 	state.push_options = push_options;
-	status = run_and_feed_hook(hook_name, feed_receive_hook, &state);
+	status = run_and_feed_hook(hook_name, feed_receive_hook, NULL, &state);
 	strbuf_release(&state.buf);
 	return status;
 }
@@ -853,6 +866,23 @@ static int run_update_hook(struct command *cmd)
 	return finish_command(&proc);
 }
 
+static void prepare_post_receive_env(int in)
+{
+	struct strbuf stdout_buf = STRBUF_INIT;
+
+	while (strbuf_getwholeline_fd(&stdout_buf, in, '\n') != EOF) {
+		char *p = stdout_buf.buf + stdout_buf.len -1;
+		if (*p =='\n')
+			*p = '\0';
+		p = strchr(stdout_buf.buf, '=');
+		if (p == NULL)
+			continue;
+		argv_array_push(&post_receive_env_array, stdout_buf.buf);
+		strbuf_reset(&stdout_buf);
+	}
+	strbuf_release(&stdout_buf);
+}
+
 static int run_proc_receive_hook(struct command *commands,
 				 const struct string_list *push_options)
 {
@@ -869,7 +899,8 @@ static int run_proc_receive_hook(struct command *commands,
 		return 0;
 	state.cmd = commands;
 	state.push_options = push_options;
-	status = run_and_feed_hook("proc-receive", feed_receive_hook, &state);
+	status = run_and_feed_hook("proc-receive",
+			feed_receive_hook, prepare_post_receive_env, &state);
 	strbuf_release(&state.buf);
 	return status;
 }
@@ -2040,6 +2071,7 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 	};
 
 	string_list_init(&proc_receive_refs, 0);
+	argv_array_init(&post_receive_env_array);
 
 	packet_trace_identity("receive-pack");
 
diff --git a/t/t5411-proc-receive-hook.sh b/t/t5411-proc-receive-hook.sh
index e3bb421078..6f35867e85 100755
--- a/t/t5411-proc-receive-hook.sh
+++ b/t/t5411-proc-receive-hook.sh
@@ -687,4 +687,74 @@ test_expect_success "(6) push both a normal and a special refs (declined)" '
 	test_cmp expect actual
 '
 
+test_expect_success "(7) restore pre-receive hook" '
+	mv $bare/hooks/pre-receive $bare/hooks/pre-receive.fail &&
+	mv $bare/hooks/pre-receive.ok $bare/hooks/pre-receive
+'
+
+test_expect_success "(7) new proc-receive and post-receive hooks (pass environment variables)" '
+	## proc-receive hook
+	mv $bare/hooks/proc-receive $bare/hooks/proc-receive.ok &&
+	cat >$bare/hooks/proc-receive <<-EOF &&
+	#!/bin/sh
+
+	printf >&2 "execute: proc-receive hook\n"
+
+	while read old new ref
+	do
+		printf >&2 ">> old: \$old, new: \$new, ref: \$ref.\n"
+	done
+
+	printf "GIT_VAR1=var1\n"
+	printf "GIT_VAR2=var2\n"
+	printf "AGIT_VAR1=foo\n"
+	printf "AGIT_VAR2=bar\n"
+	EOF
+	chmod a+x $bare/hooks/proc-receive &&
+
+	## post-receive hook
+	mv $bare/hooks/post-receive $bare/hooks/post-receive.ok &&
+	cat >$bare/hooks/post-receive <<-EOF &&
+	#!/bin/sh
+
+	printf >&2 "execute: post-receive hook\n"
+
+	while read old new ref
+	do
+		printf >&2 ">> old: \$old, new: \$new, ref: \$ref.\n"
+	done
+
+	for k in GIT_VAR1 GIT_VAR2 AGIT_VAR1 AGIT_VAR2
+	do
+		if test -n "\$(eval echo \\"\\\$\$k\")"
+		then
+			printf >&2 ">> has env: \$k=\$(eval echo \\"\\\$\$k\").\n"
+		fi
+	done
+	EOF
+	chmod a+x $bare/hooks/post-receive
+'
+
+test_expect_success "(7) push one special ref (show environments)" '
+	(
+		cd work &&
+		git push origin \
+			HEAD:refs/for/master/my/topic
+	) >out 2>&1 &&
+	grep "^remote:" out | sed -e "s/  *\$//g" >actual &&
+	cat >expect <<-EOF &&
+	remote: execute: pre-receive hook
+	remote: >> old: $ZERO_OID, new: $B, ref: refs/for/master/my/topic.
+	remote: execute: proc-receive hook
+	remote: >> old: $ZERO_OID, new: $B, ref: refs/for/master/my/topic.
+	remote: execute: post-receive hook
+	remote: >> old: $ZERO_OID, new: $B, ref: refs/for/master/my/topic.
+	remote: >> has env: GIT_VAR1=var1.
+	remote: >> has env: GIT_VAR2=var2.
+	remote: >> has env: AGIT_VAR1=foo.
+	remote: >> has env: AGIT_VAR2=bar.
+	EOF
+	test_cmp expect actual
+'
+
 test_done
-- 
2.26.0.rc0.5.gb02b988a14.dirty