Include page path in PageData.vars error messages

[bcomnes]

Closes #233

When a page vars module throws (syntax error, missing import, runtime exception at access time), the vars getter re-threw the error with no context about which page caused it. On a large site with pages spanning many directories, finding the broken page required manually bisecting the whole tree.

This wraps the getter body in a try/catch and re-throws with the page path included in the message:

Failed to resolve vars for page "2015/01/some-post": Cannot read properties of undefined

The original error is preserved as cause so nothing is lost. The fix only adds context to errors that were already being thrown; it does not change any behavior for pages that resolve successfully.

A side effect is that users who previously had to write defensive try/catch wrappers around every .vars access in global.data.js and templates will now get actionable errors instead of silently swallowed ones.

[coveralls]

Coverage Report for CI Build 24619532678

Coverage remained the same at 91.469%

Details

• Coverage remained the same as the base build.
• Patch coverage: 15 of 15 lines across 1 file are fully covered (100%).
• No coverage regressions found.

Uncovered Changes

No uncovered changes found.

Coverage Regressions

No coverage regressions found.

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Coverage Stats

Relevant Lines:	4077
Covered Lines:	3811
Line Coverage:	93.48%
Relevant Branches:	647
Covered Branches:	510
Branch Coverage:	78.83%
Branches in Coverage %:	Yes
Coverage Strength:	74.84 hits per line

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💛 - Coveralls

[Copilot]

Pull request overview

Improves debuggability of page variable resolution by adding page path context to errors thrown from the PageData.vars getter, making it easier to identify which page’s vars module caused a failure during builds.

Changes:

• Wrapped PageData.vars getter in try/catch to intercept resolution/merge failures.
• Re-threw a new error whose message includes pageInfo.path, preserving the original failure as cause.

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[bcomnes]

Acknowledged comment 3105591230. Declining to add tests in this PR for the following reason: testing the vars getter error path requires #initialized to be true, which is a private field only set by PageData.init(). init() performs file I/O and ESM module resolution, so unit-testing the error-wrapping path would require either a full integration fixture or hacking internal state via a subclass (which JS private fields prevent). That test infrastructure is a separate concern from this diagnostic improvement. Leaving it for a dedicated test PR if the error path becomes important to regression-test.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 1 comment.

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

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[bcomnes]

This looks good to land.