feat: use PG_MODULE_MAGIC_EXT in PostgreSQL 18 and later

[jeltz]

The PG_MODULE_MAGIC_EXT macro was added in PostgreSQL 18 and makes it possible to see which version of the library is actually loaded using pg_get_loaded_modules().

I updated the change log myself, just tell me if that is against the project practice.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

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Configuration used: Organization UI

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Run ID: a1082354-ce0a-47c9-ad69-9a50562428aa

📥 Commits

Reviewing files that changed from the base of the PR and between 5558840 and 05f4d86.

📒 Files selected for processing (2)

• CHANGELOG.md
• h3_postgis/src/config.h.in

✅ Files skipped from review due to trivial changes (2)

• h3_postgis/src/config.h.in
• CHANGELOG.md

---

📝 Walkthrough

Walkthrough

Adds build-time config header generation for h3_postgis and updates both h3 and h3_postgis init files to conditionally use PG_MODULE_MAGIC_EXT on PostgreSQL 18+ while maintaining PG_MODULE_MAGIC for older PostgreSQL versions. CHANGELOG updated to mention the change.

Changes

PostgreSQL 18+ Compatibility

Layer / File(s)	Summary
h3_postgis Configuration Infrastructure h3_postgis/src/config.h.in, h3_postgis/CMakeLists.txt	New config.h.in template defines POSTGRESQL_PGH3_VERSION and CMake configure_file generates src/config.h; build directory added to target include paths.
h3_postgis Module Initialization h3_postgis/src/init.c	Include generated config.h and conditionally use PG_MODULE_MAGIC_EXT on PostgreSQL 18+ with module name/version, falling back to PG_MODULE_MAGIC.
h3 Extension Module Initialization h3/src/init.c	Include config.h and conditionally use PG_MODULE_MAGIC_EXT on PostgreSQL 18+ with module name and POSTGRESQL_H3_VERSION, falling back to PG_MODULE_MAGIC.
Release Notes CHANGELOG.md	Add changelog bullet under Unreleased documenting the PG_MODULE_MAGIC_EXT requirement for PostgreSQL 18+ and update reference link definitions.

🎯 3 (Moderate) | ⏱️ ~20 minutes

I nibble at headers, stitch version threads,
Configure and build where the tiny token treads.
Magic hops to eighteen, politely stays back when not,
A rabbit's tidy patch — a lightweight spot. 🐇✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The pull request title accurately and concisely describes the main change: adopting PG_MODULE_MAGIC_EXT for PostgreSQL 18 and later.
Description check	✅ Passed	The description explains the purpose of the change (PG_MODULE_MAGIC_EXT enables version visibility in pg_get_loaded_modules) and relates directly to the changeset modifications.
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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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@CHANGELOG.md`:
- Line 25: Fix the typo in the CHANGELOG entry referring to PostgreSQL: update
the release note line that mentions "Use `PG_MODULE_MAGIC_EXT` macro in
PostgreSQL 18 an later ([Andreas Karlsson])" to read "and later" instead of "an
later" so the text becomes "Use `PG_MODULE_MAGIC_EXT` macro in PostgreSQL 18 and
later ([Andreas Karlsson])"; ensure the `PG_MODULE_MAGIC_EXT` mention and author
attribution remain unchanged.

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Fix all unresolved CodeRabbit comments on this PR:

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• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 2bbad8a7-46be-4e0f-8980-52d94e4bf88d

📥 Commits

Reviewing files that changed from the base of the PR and between 5319a1d and 2045995.

📒 Files selected for processing (5)

• CHANGELOG.md
• h3/src/init.c
• h3_postgis/CMakeLists.txt
• h3_postgis/src/config.h.in
• h3_postgis/src/init.c

[Komzpa]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Can't wait for the next one!

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[Komzpa]

@codex can you fix this in the branch?

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[Komzpa]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Another round soon, please!

ℹ️ About Codex in GitHub

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[Komzpa]

@jeltz thank you!

[jeltz]

Thanks for the speedy merge!