Turbopack: properly set NODE_ENV for SWC plugins#92579
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Webpack didn't correctly load relative paths for `swcPlugins`. #92579 will add a test
…builds Thread the actual build mode (NextMode) through to SwcEcmaTransformPluginsTransformer so that TransformPluginMetadataContext receives "production" during `next build` instead of the previously hardcoded "development" string. Fixes #92547 Store node_env in TransformContext instead of SwcEcmaTransformPluginsTransformer The SWC plugin transformer was storing node_env as a field on the struct, which caused it to be locked in at plugin construction time from NextMode. Instead, derive node_env from process.env.NODE_ENV compile-time defines in EcmascriptModuleAsset::parse() and thread it through TransformContext so each file transformation sees the correct environment value. Thread compile_time_info through webpack path to eliminate hardcoded node_env strings Extract node_env_from_compile_time_info() as a shared helper in parse.rs and use it from both EcmascriptModuleAsset::parse() and the webpack analysis path. Thread compile_time_info through WebpackModuleAsset, WebpackChunkAssetReference, WebpackEntryAssetReference, WebpackRuntimeAssetReference, webpack_runtime(), and module_references() so that SWC plugin transforms on webpack bundles also see the correct NODE_ENV. Add a comment in segment_config.rs explaining why the node_env value is irrelevant there (EcmascriptInputTransforms::empty() = no transforms run). Co-Authored-By: Claude <noreply@anthropic.com>
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What?
Closes #92650
Closes #92547
When Turbopack runs SWC transform plugins, it passes a
TransformPluginMetadataContextthat includes the currentNODE_ENV. Previously this value was hardcoded to"development"regardless of the actual build mode, causing SWC plugins to misbehave during production builds.Why?
SwcPluginMetadataContextis used by SWC plugins (e.g.babel-plugin-styled-components,@swc/plugin-emotion) to conditionally produce development vs. production output — for instance, injecting display names and data attributes only in development. WithNODE_ENValways set to"development", plugins could never produce their optimised production output, resulting in larger bundles and missing minification innext build.Fixes #92547
How?
NODE_ENVis now derived from theprocess.env.NODE_ENVcompile-time define that is already part ofCompileTimeInfo(the same source of truth used for dead-code elimination). The resolution happens inEcmascriptModuleAsset::parse()via a new shared helpernode_env_from_compile_time_info()inparse.rs, and the value is stored onTransformContextso everyCustomTransformerimplementation can read it fromctx.node_envwithout needing access to the broader compilation context.Key design decisions:
TransformContextis the right place: it is the per-file context passed to everyCustomTransformer::transform()call, so storingnode_envthere follows the existing pattern and avoids coupling the plugin struct to the build mode.compile_time_infois now threaded throughwebpack_runtime(),module_references(), and the webpack reference structs (WebpackModuleAsset,WebpackChunkAssetReference,WebpackEntryAssetReference,WebpackRuntimeAssetReference) so that webpack-bundled files with SWC plugin transforms also receive the correctNODE_ENV.segment_config.rs: passes a placeholder but includes a comment explaining it is irrelevant sinceEcmascriptInputTransforms::empty()means no transforms run.