Add support for x_google_ignoreList

[bmeurer]

Feature Use Case

Chrome DevTools introduced¹ support for a new x_google_ignoreList source map extension² last year, which allows to libraries / frameworks to have their code automatically ignore-listed in the debugger, meaning that files will not show up or if shown will be grayed out, stepping and breaking on exceptions will ignore these files by default, etc.

Feature Proposal

We propose¹ two sets of changes in rollup to leverage the ignore-listing effectively.

1. Introduce a sourcemapIgnoreList predicate similar to the sourcemapPathTransform callback. The sourcemapIgnoreList predicate (when provided) will be called with the same inputs as the sourcemapPathTransform callback and if the result is true, the corresponding sources entry in the source map will be added to the x_google_ignoreList. The sourcemapIgnoreList predicate (when provided) will always be called before the sourcemapPathTransform callback.
2. Preserve (and repopulate) x_google_ignoreList annotations from input source maps and other transforms.

Ref: Rich-Harris/magic-string#241

Footnotes

1. https://developer.chrome.com/blog/devtools-better-angular-debugging ↩ ↩²

2. https://docs.google.com/document/d/1U1RGAehQwRypUTovF1KRlpiOFze0b-_2gc6fAH0KY0k/edit#heading=h.mt2g20loc2ct ↩

[0xdevalias]

@bmeurer I believe this is already implemented now, right?

• Update magic-string and adjust types. #4846
• Introduce sourcemapIgnoreList config predicate #4848
• docs: Update the x_google_ignorelist url #4926

[bmeurer]

@bmeurer I believe this is already implemented now, right?

• Update magic-string and adjust types. #4846
• Introduce sourcemapIgnoreList config predicate #4848
• docs: Update the x_google_ignorelist url #4926

No, rollup doesn't propagate x_google_ignoreList from input source maps yet. Also it needs to be updated to support ignoreList.

[0xdevalias]

No, rollup doesn't propagate x_google_ignoreList from input source maps yet. Also it needs to be updated to support ignoreList.

@bmeurer Ah true, that makes sense. Thanks.

---

Further details on the change from x_google_ignoreList to ignoreList here:

• https://developer.chrome.com/blog/new-in-devtools-120/#ignore-list-spec

  • The source maps specification has adopted the ignoreList field instead of x_google_ignoreList and DevTools now supports the new name with a fallback for the old one. Frameworks and bundlers can now use the new field name.

Originally posted by @0xdevalias in facebook/react#27774 (comment)

• Deprecate x_google_ignoreList in favor of ignoreList, remove Known Extensions tc39/source-map-spec#19
• https://tc39.es/source-map-spec/#ignorelist