Consistently use the XLogRecPtrIsInvalid() macro

Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

From: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>

To: pgsql-hackers@lists.postgresql.org

Date: 2025-10-28T08:13:06Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Replace literal 0 with InvalidXLogRecPtr for XLogRecPtr assignments
- ec3174407164 19 (unreleased) landed
Replace pointer comparisons and assignments to literal zero with NULL
- ec782f56b0c3 19 (unreleased) landed
Use XLogRecPtrIsValid() in various places
- a2b02293bc65 19 (unreleased) landed
Introduce XLogRecPtrIsValid()
- d2965f627fe3 14.20 landed
- c0031d461324 18.1 landed
- 723cc84db50a 16.11 landed
- 49b45999f3b2 15.15 landed
- 33727aff18d0 17.7 landed
- 20bafb097288 13.23 landed
- 06edbed47862 19 (unreleased) landed

Attachments

v1-0001-make-use-of-XLogRecPtrIsInvalid-in-rewriteheap.c.patch (text/x-diff)

Hi hackers,

While working on refactoring some code in [1], one of the changes was:

-       if (initial_restart_lsn != InvalidXLogRecPtr &&
-           initial_restart_lsn < oldestLSN)
+       XLogRecPtr  restart_lsn = s->data.restart_lsn;
+
+       if (restart_lsn != InvalidXLogRecPtr &&
+           restart_lsn < oldestLSN)

Sawada-san suggested to use the XLogRecPtrIsInvalid() macro here.

But this != InvalidXLogRecPtr check was existing code, so why not consistently
use XLogRecPtrIsInvalid() where we check equality against InvalidXLogRecPtr?

At the time the current XLogRecPtrIsInvalid() has been introduced (0ab9d1c4b316)
all the InvalidXLogRecPtr equality checks were done using XLogRecPtrIsInvalid().

But since, it has changed: I looked at it and this is not the case anymore in
20 files.

PFA, patches to $SUBJECT.  To ease the review, I created one patch per modified
file.

I suspect the same approach could be applied to some other macros too.  Let's
start with XLogRecPtrIsInvalid() first.

I think that's one of the things we could do once a year, like Peter does with
his annual "clang-tidy" check ([2]).

Thoughts?

[1]: https://www.postgresql.org/message-id/CAD21AoB_C6V1PLNs%3DSuOejgGh1o6ZHJMstD7X4X1b_z%3D%3DLdH1Q%40mail.gmail.com
[2]: https://www.postgresql.org/message-id/CAH2-WzmxPQAF_ZhwrUo3rzVk3yYj_4mqbgiQXAGGO5nFYV3D8Q@mail.gmail.com

Regards,

-- 
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com