@matheusbsbs / matheus-bagliano / commits / a8ae923f85

refs: support symrefs in 'reference-transaction' hook

The 'reference-transaction' hook runs whenever a reference update is made to the system. In a previous commit, we added the `old_target` and `new_target` fields to the `reference_transaction_update()`. In following commits we'll also add the code to handle symref's in the reference backends. Support symrefs also in the 'reference-transaction' hook, by modifying the current format: <old-oid> SP <new-oid> SP <ref-name> LF to be be: <old-value> SP <new-value> SP <ref-name> LF where for regular refs the output would not change and remain the same. But when either 'old-value' or 'new-value' is a symref, we print the ref as 'ref:<ref-target>'. This does break backward compatibility, but the 'reference-transaction' hook's documentation always stated that support for symbolic references may be added in the future. We do not add any tests in this commit since there is no git command which activates this flow, in an upcoming commit, we'll start using transaction based symref updates as the default, we'll add tests there for the hook too. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Karthik Nayak committed May 7, 2024 at 14:58 UTC a8ae923f85da6434c3faf9c39719d6d5e5c77e65

2 files changed +25 -9

Documentation/githooks.txt

+9 -5

@@ -486,7 +486,7 @@ reference-transaction

486 This hook is invoked by any Git command that performs reference

487 updates. It executes whenever a reference transaction is prepared,

488 committed or aborted and may thus get called multiple times. The hook

489 -does not cover symbolic references (but that may change in the future).

489 +also supports symbolic reference updates.

490

491 The hook takes exactly one argument, which is the current state the

492 given reference transaction is in:

@@ -503,16 +503,20 @@ given reference transaction is in:

503 For each reference update that was added to the transaction, the hook

504 receives on standard input a line of the format:

505

506 - <old-oid> SP <new-oid> SP <ref-name> LF

506 + <old-value> SP <new-value> SP <ref-name> LF

507

508 -where `<old-oid>` is the old object name passed into the reference

509 -transaction, `<new-oid>` is the new object name to be stored in the

508 +where `<old-value>` is the old object name passed into the reference

509 +transaction, `<new-value>` is the new object name to be stored in the

510 ref and `<ref-name>` is the full name of the ref. When force updating

511 the reference regardless of its current value or when the reference is

512 -to be created anew, `<old-oid>` is the all-zeroes object name. To

512 +to be created anew, `<old-value>` is the all-zeroes object name. To

513 distinguish these cases, you can inspect the current value of

514 `<ref-name>` via `git rev-parse`.

515

516 +For symbolic reference updates the `<old_value>` and `<new-value>`

517 +fields could denote references instead of objects. A reference will be

518 +denoted with a 'ref:' prefix, like `ref:<ref-target>`.

519 +

520 The exit status of the hook is ignored for any state except for the

521 "prepared" state. In the "prepared" state, a non-zero exit status will

522 cause the transaction to be aborted. The hook will not be called with

refs.c

+16 -4

@@ -2350,10 +2350,22 @@ static int run_transaction_hook(struct ref_transaction *transaction,

2350 struct ref_update *update = transaction->updates[i];

2351

2352 strbuf_reset(&buf);

2353 - strbuf_addf(&buf, "%s %s %s\n",

2354 - oid_to_hex(&update->old_oid),

2355 - oid_to_hex(&update->new_oid),

2356 - update->refname);

2353 +

2354 + if (!(update->flags & REF_HAVE_OLD))

2355 + strbuf_addf(&buf, "%s ", oid_to_hex(null_oid()));

2356 + else if (update->old_target)

2357 + strbuf_addf(&buf, "ref:%s ", update->old_target);

2358 + else

2359 + strbuf_addf(&buf, "%s ", oid_to_hex(&update->old_oid));

2360 +

2361 + if (!(update->flags & REF_HAVE_NEW))

2362 + strbuf_addf(&buf, "%s ", oid_to_hex(null_oid()));

2363 + else if (update->new_target)

2364 + strbuf_addf(&buf, "ref:%s ", update->new_target);

2365 + else

2366 + strbuf_addf(&buf, "%s ", oid_to_hex(&update->new_oid));

2367 +

2368 + strbuf_addf(&buf, "%s\n", update->refname);

2369

2370 if (write_in_full(proc.in, buf.buf, buf.len) < 0) {

2371 if (errno != EPIPE) {