[PATCH v5 0/3] hook: introduce the receive-report hook
- From
Karthik Nayak <karthik.188@gmail.com>
- Date
- Sep 1, 2026, 15:19 UTC
- Message-ID
- <20260901-758-introduce-hook-v5-0-35cdc6be3cc1@gmail.com>
- In-Reply-To
- <20260818-758-introduce-hook-v1-1-8a8d89e65838@gmail.com>
Introduce a new receive-report hook which kicks in after the reference transaction is complete, but before the report is sent to the client. The hook receives the pkt-line encoded report in its stdin and its stdout replaces the report transferred to the user. If the hook exits with a non-zero exit code, all references are marked as rejected.
The first patch, adds missing documentation to 'git-receive-pack.adoc'. The second patch refactors code and the third patch contains the new hook.
---
Changes in v5:
- Rewrote some of the commit messages and documentation.
- Renamed the function `generate_response` to `generate_report` to avoid
ambiguity.
- We now override the cmd's error_strings, this avoids the whole
precedence issue with the earlier series.
- Also add information about how we can override the unpack status to
fail the push and add a corresponding test.
- Thanks to Patrick for the review!
- Junio: This causes conflict with next ('jt/receive-pack-pluggable-writes')
similar to before, please let me know if its better for me to add that
dependency.
- Link to v4: https://patch.msgid.link/20260826-758-introduce-hook-v4-0-6b14975ad957@gmail.comChanges in v4: - Change the name of the hook to be 'receive-report' to avoid ambiguity. - Link to v3: https://patch.msgid.link/20260824-758-introduce-hook-v3-0-499526f0a062@gmail.com
Changes in v3: - Move out addition of proc-receive hook doc to 'git-receive-pack.adoc' into a new commit. - Add a new commit to move out the response generation in receive-pack to a new function. - Instead of die-ing on non-zero exit code, we modify each reference to indicate that the hook failed. - Instead of correctly listing out the protocol, link to linkgit:gitprotocol-pack[5], as the protocol also differs between v1 and v2. - Link to v2: https://patch.msgid.link/20260821-758-introduce-hook-v2-1-e90e2f7ac2cf@gmail.com
Changes in v2: - Modify the documentation and commit message to be more verbose. - Add documentation to 'git-receive-pack.adoc' - Use 'ret' as the variable name for the return code. - Modify the test to also check for the 'remote:'. - Link to v1: https://patch.msgid.link/20260818-758-introduce-hook-v1-1-8a8d89e65838@gmail.com
To: git@vger.kernel.org CC: ps@pks.im CC: gitster@pobox.com CC: jltobler@gmail.com CC: kristofferhaugsbakk@fastmail.com CC: phillip.wood123@gmail.com
---
Karthik Nayak (3):
doc: add proc-receive hook info in 'git-receive-pack.adoc'
receive-pack: move message generation to separate function
hook: introduce the receive-report hookDocumentation/git-receive-pack.adoc | 17 +++ Documentation/githooks.adoc | 47 ++++++++ builtin/receive-pack.c | 132 +++++++++++++++------ t/meson.build | 1 + t/t5412-receive-report-hook.sh | 224 ++++++++++++++++++++++++++++++++++++ 5 files changed, 384 insertions(+), 37 deletions(-)
Range-diff versus v4:
1: 6b173f391d < -: ---------- doc: add proc-receive hook info in 'git-receive-pack.adoc'
-: ---------- > 1: cb32302829 doc: add proc-receive hook info in 'git-receive-pack.adoc'
2: 24e3e651ff ! 2: ad3394490e receive-pack: move message generation to separate function
@@ Metadata
## Commit message ##
receive-pack: move message generation to separate function
- Post the reference transaction, both `report()` and `report_v2()`
- generate the message to be sent to the client. In v2, we also add
- reports for each reference if available. Since they share common code,
- move them to a common function. This will also help the following
- commit, where we will need to regenerate the message during hook
- failure.
+ After git-receive-pack(1) has committed the reference updates, we call
+ either `report()` or `report_v2()` to report to the client which of the
+ references we have updated successfully and which updates have failed.
+ The only difference between those two functions is that the latter also
+ knows to provide a more detailed report about how exactly a given
+ reference was updated.
+ In the next commit we're about to add another site that wants to
+ generate these reports. Refactor the logic into a shared function that
+ can easily be reused.
+
+ Helped-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
## builtin/receive-pack.c ##
@@ builtin/receive-pack.c: static void update_shallow_info(struct command *commands
-static void report(struct command *commands, const char *unpack_status)
+/*
+ * Generate the response to be sent to the client invoking 'git-receive-pack(1)'.
-+ * For v2 protocol, set `add_reports` to true, which will also add additional
++ * For v2 protocol, set `detailed_report` to true, which will also add detailed
+ * report per reference update.
+ */
-+static void generate_response(struct strbuf *buf, struct command *commands,
-+ const char *unpack_status, bool add_reports)
++static void generate_report(struct strbuf *buf, struct command *commands,
++ const char *unpack_status, bool detailed_report)
{
struct command *cmd;
- struct strbuf buf = STRBUF_INIT;
@@ builtin/receive-pack.c: static void update_shallow_info(struct command *commands
+ else
+ packet_buf_write(buf, "ok %s\n", cmd->ref_name);
+
-+ if (!add_reports || cmd->error_string)
++ if (!detailed_report || cmd->error_string)
continue;
- }
- packet_buf_write(&buf, "ok %s\n",
@@ builtin/receive-pack.c: static void update_shallow_info(struct command *commands
+{
+ struct strbuf buf = STRBUF_INIT;
+
-+ generate_response(&buf, commands, unpack_status, false);
++ generate_report(&buf, commands, unpack_status, false);
+
+ if (use_sideband)
+ send_sideband(1, 1, buf.buf, buf.len, use_sideband);
@@ builtin/receive-pack.c: static void update_shallow_info(struct command *commands
+{
+ struct strbuf buf = STRBUF_INIT;
+
-+ generate_response(&buf, commands, unpack_status, true);
++ generate_report(&buf, commands, unpack_status, true);
if (use_sideband)
send_sideband(1, 1, buf.buf, buf.len, use_sideband);
3: d6c98d2693 ! 3: a24ca1141d hook: introduce the receive-report hook
@@ Commit message
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
## Documentation/git-receive-pack.adoc ##
-@@ Documentation/git-receive-pack.adoc: requests. It handles refs whose names match the patterns defined by
- `receive.procReceiveRefs` and executes the actual ref updates. See
- linkgit:githooks[5] for the full protocol description.
+@@ Documentation/git-receive-pack.adoc: commands will be executed by this hook, instead of by the internal
+ `execute_commands()` function. This hook is responsible for updating
+ the relevant references and reporting the results back to 'receive-pack'.
+RECEIVE-REPORT HOOK
+-------------------
+This hook is invoked by 'git-receive-pack' after all the ref updates
+have been applied but before the report is sent to the client. The hook
+receives the complete report in pkt-line format on stdin and its stdout
-+replaces the report sent to the client. Allowing the hook to rewrite
++replaces the report sent to the client, which allows the hook to rewrite
+the outcomes or abort the push completely. See linkgit:githooks[5] for
+the full protocol description.
+
@@ Documentation/githooks.adoc: The exit status of the hook is ignored for any stat
+fully buffered by `receive-pack` before any data is sent to the client,
+so the hook's exit status is known before the client receives anything.
+
-+There are two distinct ways the hook can affect the push outcome:
++There are three distinct ways the hook can affect the push outcome:
++
++* To reject the push, modify the unpack status from `ok` to the required
++ error message. While `git-push` will fail, individual references may
++ still show success messages unless modified.
+
+* To reject individual ref updates while keeping `receive-pack` alive,
+ rewrite the corresponding `ok <refname>` lines to
-+ `ng <refname> <reason>` lines in the output and exit with status 0.
++ `ng <refname>[ <reason>]` lines in the output and exit with status 0.
+ The client will then mark those specific refs as rejected while
+ treating any `ok` refs as successful. The push as a whole is
+ considered failed if any ref is `ng`, and `git push` will exit with
@@ builtin/receive-pack.c: static int run_update_hook(struct command *cmd)
const char *refname)
{
@@ builtin/receive-pack.c: static void update_shallow_info(struct command *commands,
- * Generate the response to be sent to the client invoking 'git-receive-pack(1)'.
- * For v2 protocol, set `add_reports` to true, which will also add additional
- * report per reference update.
-+ * If `ref_error` is set, then all references will be rejected with the given
-+ * error message.
- */
- static void generate_response(struct strbuf *buf, struct command *commands,
-- const char *unpack_status, bool add_reports)
-+ const char *unpack_status, bool add_reports,
-+ const char *ref_error)
- {
- struct command *cmd;
-
-@@ builtin/receive-pack.c: static void generate_response(struct strbuf *buf, struct command *commands,
- if (cmd->error_string)
- packet_buf_write(buf, "ng %s %s\n",
- cmd->ref_name, cmd->error_string);
-+ else if (ref_error)
-+ packet_buf_write(buf, "ng %s %s\n",
-+ cmd->ref_name, ref_error);
- else
- packet_buf_write(buf, "ok %s\n", cmd->ref_name);
-
-- if (!add_reports || cmd->error_string)
-+ if (!add_reports || cmd->error_string || ref_error)
- continue;
+ free(ref_status);
+ }
- for (report = cmd->report; report; report = report->next) {
++static void override_cmds_error(struct command *commands, const char *err)
++{
++ for (struct command *cmd = commands; cmd; cmd = cmd->next) {
++ cmd->error_string = err;
++ }
++}
++
+ /*
+ * Generate the response to be sent to the client invoking 'git-receive-pack(1)'.
+ * For v2 protocol, set `detailed_report` to true, which will also add detailed
@@ builtin/receive-pack.c: static void report(struct command *commands, const char *unpack_status)
- {
- struct strbuf buf = STRBUF_INIT;
-- generate_response(&buf, commands, unpack_status, false);
-+ generate_response(&buf, commands, unpack_status, false, NULL);
-+
+ generate_report(&buf, commands, unpack_status, false);
+
+ if (run_receive_report_hook(&buf)) {
+ strbuf_reset(&buf);
-+ generate_response(&buf, commands, unpack_status, false,
-+ "receive-report hook failed");
++ override_cmds_error(commands, "receive-report hook failed");
++ generate_report(&buf, commands, unpack_status, false);
+ }
-
++
if (use_sideband)
send_sideband(1, 1, buf.buf, buf.len, use_sideband);
+ else
@@ builtin/receive-pack.c: static void report_v2(struct command *commands, const char *unpack_status)
- {
- struct strbuf buf = STRBUF_INIT;
-- generate_response(&buf, commands, unpack_status, true);
-+ generate_response(&buf, commands, unpack_status, true, NULL);
-+
+ generate_report(&buf, commands, unpack_status, true);
+
+ if (run_receive_report_hook(&buf)) {
+ strbuf_reset(&buf);
-+ generate_response(&buf, commands, unpack_status, true,
-+ "receive-report hook failed");
++ override_cmds_error(commands, "receive-report hook failed");
++ generate_report(&buf, commands, unpack_status, true);
+ }
-
++
if (use_sideband)
send_sideband(1, 1, buf.buf, buf.len, use_sideband);
+ else
## t/meson.build ##
@@ t/meson.build: integration_tests = [
@@ t/t5412-receive-report-hook.sh (new)
+ test_cmp expect actual
+'
+
++test_expect_success "hook can modify the unpack status" '
++ test_when_finished "rm -rf upstream" &&
++ test_when_finished "git -C workbench remote remove origin" &&
++
++ git init --bare upstream &&
++ git -C workbench remote add origin ../upstream &&
++ git -C workbench push origin $A:refs/heads/main &&
++
++ test_hook -C upstream --setup receive-report <<-\EOF &&
++ test-tool pkt-line unpack |
++ sed "s/^unpack ok$/unpack push failed due to server error/" |
++ test-tool pkt-line pack
++ EOF
++
++ test_must_fail git -C workbench push origin $B:refs/heads/main >out 2>&1 &&
++ test_grep "error: remote unpack failed: push failed due to server error" out &&
++ make_user_friendly_and_stable_output <out >actual &&
++ cat >expect <<-\EOF &&
++ To ../upstream
++ <COMMIT-A>..<COMMIT-B> <COMMIT-B> -> main
++ EOF
++ test_cmp expect actual
++'
++
+test_expect_success "hook can report a custom failure message" '
+ test_when_finished "rm -rf upstream" &&
+ test_when_finished "git -C workbench remote remove origin" &&--- base-commit: 11c6700f10234578d10523faf35656ca491425c9 change-id: 20260812-758-introduce-hook-5b3af9f1a7e8
Thanks - Karthik