[0.73.x] Release 0.73.8 (Terser source map fixes) #930
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…928) Summary: Pull Request resolved: #928 Fixes #927 Terser, unlike the previous default minifier UglifyES, produces source maps whose entries may contain "simple mappings" - that is entries with a generated line+col but no original location. When Metro processes minified output ahead of serialization, it doesn't correctly handle these entries. Instead it incorrectly detects them as complete mappings and produces a merged source map with `-1` origin line numbers in place of simple mappings. Some tools will reject the whole source map (which is otherwise correct) based on the appearance of a negative line number. The issue comes down to the conversion of raw mappings to `BabelSourceMapSegments` in `toBabelSegments`, which currently generates entries for simple mappings with `null` `origin` *properties*, such as: ``` { generated: { column: 2, line: 1 }, origin: { column: null, line: null }, // ... } ``` According to the Flow type for `BabelSourceMapSegments`, that's incorrect. `origin` itself is optional and should be missing - the properties of `origin` are not nullable. Based on the presence of the `origin` property in that object, `toSegmentTuple` generates a 4-tuple and we go on to add a "source mapping" rather than a "simple mapping". This fixes `toBabelSegments` to omit `origin` unless `line` and `column` are both populated. The final source map output is then correct. Changelog: [Fix] Source maps may have invalid entries when using Terser minification. Reviewed By: motiz88 Differential Revision: D43351987 fbshipit-source-id: 5cd46fdd001f3c3a3599ada44f525bec467854e1
Summary: Mitigates terser/terser#1341 Terser sets properties inlcuding `source_map` and `_destroy_ast` on the given `options.output` (or `options.format`) object, which can affect subsequent calls where we re-use the same config object. Here we take a shallow copy of the given configuration, so `terser` doesn't mutate `metro-minify-terser`'s input. Changelog: [Fix] Mitigate potential source map mismatches with concurrent transformations (Terser [#1341](terser/terser#1341)) Reviewed By: jacdebug, motiz88 Differential Revision: D43362977 fbshipit-source-id: 940e6209273cdd382513aea2f2a8aeca12daa2e3
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Release 0.73.8 as a hotfix to address two recent issues, coincidentally both with source maps, revealed as we've switched the default minifier to Terser.
Fixes: #927
Mitigates: terser/terser#1341
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