Place pg_noreturn before extern so C23 compilers accept it

[maqeel75]

Problem

The v1.1-beta1 release run failed on one cell — Package DEB (ubuntu:resolute amd64 pg19):

src/pgedge_vectorizer.h:194:36: error: expected identifier or '(' before 'void'
194 | extern PGDLLEXPORT PGEDGE_NORETURN void pgedge_vectorizer_launcher_main(...)

PGEDGE_NORETURN expands to PostgreSQL's pg_noreturn, which PG19 defines as the C23
[[noreturn]] attribute when __STDC_VERSION__ >= 202311L. C23 only permits an attribute
list at the start of a declaration, so placing it between the storage class and the return
type is a syntax error. Ubuntu resolute ships gcc 15, which defaults to -std=gnu23 — the
only image in the matrix that reaches that branch. PG19's own c.h notes the requirement:
"C23 attributes must be placed at the start of a declaration."

Fix

Move PGEDGE_NORETURN ahead of extern on the two worker entry-point declarations, matching
how PostgreSQL's own headers spell it, and document why the order matters.

Compatibility

No behavior change on any other cell:

• pg16/17 — no pg_noreturn; PGEDGE_NORETURN is empty and the suffix
  pg_attribute_noreturn() is unchanged.
• pg18 — _Noreturn, a C11 function specifier, valid anywhere in the declaration specifiers.
• pg19 on gcc ≤14 — also _Noreturn; only gcc 15's C23 default produces [[noreturn]].

[codacy-production]

Up to standards ✅

🟢 Issues 0 issues

Results:
0 new issues

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🟢 Metrics 0 complexity · 0 duplication

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Duplication	0

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[coderabbitai]

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• src/pgedge_vectorizer.h

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📝 Walkthrough

Walkthrough

The header now documents PostgreSQL 18+ pg_noreturn compatibility and C23 attribute-placement requirements. The PGEDGE_NORETURN macro now appears before extern in the launcher and worker declarations. The declarations retain their existing function signatures and suffix attributes.

Merge Risk: ⚪ Minimal · up to 04f3e

This localized header change fixes C23 compilation for the affected build while preserving behavior on other supported PostgreSQL versions; no actionable merge-blocking risk remains beyond normal checks and review.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely identifies the C23 compatibility fix in the declarations.
Description check	✅ Passed	The description explains the compilation failure, the fix, and compatibility across supported PostgreSQL versions.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
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.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/pg-noreturn-c23

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[dpage]

Independently verified: I hit this exact failure packaging v1.1-beta1 (ubuntu:resolute/pg19), traced it to the same root cause, and reproduced both the break and this fix locally with gcc -std=c23. Diff is identical to the fix I'd drafted, plus a nice explanatory comment mine lacked.