Fix wal2mongo build failures against PostgreSQL 17, 18, and 19.

[devrimgunduz]

PG 17 / 18:

• change->data.tp.newtuple and oldtuple changed type from ReorderBufferTupleBuf * (requiring ->tuple dereference to obtain HeapTupleData) to bare HeapTuple. Drop the ->tuple member access and pass the pointer directly to tuple_to_stringinfo() for all five call sites (INSERT, UPDATE old/new/pkAttrs, DELETE).

PG 19:

• RepOriginId renamed to ReplOriginId; InvalidRepOriginId renamed to InvalidReplOriginId. Update forward declaration, function definition, and the only_local guard accordingly.
• AssertVariableIsOfType() removed; replace with StaticAssertVariableIsOfType() which performs the same check at compile time.
• VARATT_IS_EXTERNAL_ONDISK(), VARSIZE_ANY_EXHDR(), and VARDATA_ANY() now take const void * instead of accepting Datum implicitly. Wrap the Datum arguments with DatumGetPointer() at the three affected call sites.

All versions:

• Remove always-true (valptr+1) != NULL guard in print_w2m_literal(). Pointer arithmetic on a non-null pointer never yields NULL; the compiler correctly warns about this. The *(valptr+1) read is safe regardless: the loop iterates while *valptr != '\0', so valptr+1 is always within the string or pointing at the null terminator, neither of which requires a NULL check.

All changes are guarded with appropriate #if PG_VERSION_NUM >= NNNNNN blocks to preserve backwards compatibility with PG 13-16.

pgdg-packaging/pgdg-rpms#213

Summary by CodeRabbit

• Bug Fixes
  • Improved compatibility with newer PostgreSQL versions.
  • Fixed handling of change decoding across different PostgreSQL releases, including insert, update, and delete events.
  • Adjusted string escaping and literal rendering for more reliable output.
  • Improved handling of on-disk and tuple data so decoded changes continue to render correctly across supported versions.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro

Run ID: 6c660728-54e6-41dc-a5d1-c5c08711a2c7

📥 Commits

Reviewing files that changed from the base of the PR and between 0f47e67 and 41269f2.

📒 Files selected for processing (1)

• wal2mongo.c

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📝 Walkthrough

Walkthrough

wal2mongo.c adds PostgreSQL version guards for decoder initialization, origin filtering, literal/bytea rendering, and tuple access while formatting INSERT, UPDATE, and DELETE changes.

Changes

PostgreSQL version compatibility

Layer / File(s)	Summary
Decoder init and filter checks wal2mongo.c	pg_w2m_decode_filter and _PG_output_plugin_init use PostgreSQL-version-specific origin ID types and symbol type checks.
Literal and bytea rendering wal2mongo.c	print_w2m_literal and tuple_to_stringinfo switch pointer and length handling for JSON escaping, toasted values, and bytea hex encoding across PostgreSQL versions.
Decoded change tuple access wal2mongo.c	pg_w2m_decode_change selects different tuple access forms for INSERT, UPDATE, and DELETE rendering on PostgreSQL 17+ versus older releases.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

Possibly related issues

• PostgreSQL 18 support #5 — This PR updates PostgreSQL version compatibility in wal2mongo.c, including the tuple access changes on newer PostgreSQL versions.

Poem

🐇 Hop, hop! I thump through version gates so bright,
Old tuples and new tuples dance just right.
Bytea crumbs sparkle, JSON shells gleam,
In wal2mongo burrows, the code keeps its beam.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title accurately summarizes the main change: PostgreSQL 17-19 compatibility fixes for wal2mongo build failures.
Docstring Coverage	✅ Passed	Docstring coverage is 83.33% which is sufficient. The required threshold is 80.00%.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

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