[thisisnic]

Rationale for this change

CRAN failures on 26.0.0 release due to regex not catching incompatible MacOSX11.sdk version

What changes are included in this PR?

Make regex more permissive

Are these changes tested?

No

Are there any user-facing changes?

No

PR code and description written by:

• Human
• AI

Reviewed before submission by:

• Human
• AI
• Not reviewed

• GitHub Issue: [C++][R] Arrow 26.0.0 fails to build on CRAN macOS builders: bundled simdjson C++20 concepts don't compile with the macOS 11 SDK #55267

[github-actions]

⚠️ GitHub issue #55267 has been automatically assigned in GitHub to PR creator.

[Copilot]

🟢 Approval recommended

The narrow regex change covers both documented SDK names, excludes other macOS major versions, and introduces no identified blocking issues.

No open issues 🎉

What changed in this PR

This PR fixes the bundled simdjson SDK check for CRAN macOS builds by extending the existing C++20 concepts workaround to recognize MacOSX11.sdk.

Changes:

• Broadens the regex to match macOS 11 SDK names with or without a minor version, preserving support for MacOSX11.3.sdk.
• Updates the explanatory comments and status message to reflect macOS 11 coverage.

File	Description
cpp/​cmake_modules/​ThirdpartyToolchain.cmake	Broadens macOS 11 SDK detection for the existing simdjson concepts workaround.

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

The narrow regex change covers the reported CRAN path, preserves the existing CI match, and has no identified blocking issues.

No open issues 🎉

_{Review effort: Balanced}

[thisisnic]

@github-actions crossbow submit test-r-macos-as-cran

[github-actions]

Revision: 99ff206

Submitted crossbow builds: ursacomputing/crossbow @ actions-31b1457ca7

Task	Status
test-r-macos-as-cran

[thisisnic]

Actually, the submitted CI job will fail because of #53945 but I've tested the regex locally and am happy with it

[Copilot]

🟢 Approval recommended

The localized guard change covers CRAN’s reported SDK path, preserves the existing CI match, and has no identified blocking issues.

No open issues 🎉

_{Review effort: Balanced}

[jonkeane]

Thanks for this!

Actually, the submitted CI job will fail because of #53945 but I've tested the regex locally and am happy with it

We are planning to include both this and #53946 (the PR for #53945) in the patch, yeah?

[thisisnic]

Thanks for this!

Actually, the submitted CI job will fail because of #53945 but I've tested the regex locally and am happy with it

We are planning to include both this and #53946 (the PR for #53945) in the patch, yeah?

Nah, we don't need #53946 as the PR which added the functionality which broke our CRAN builds wasn't in 26.0.0