refactor: export lexical runtime globals for esm chunks by LingyuCoder · Pull Request #14741 · web-infra-dev/rspack

LingyuCoder · 2026-07-09T12:15:54Z

Summary

add a lexical runtime-global rendering mode for the ESM output + split runtime chunk case
export runtime module globals as lexical __rspack_* bindings from the runtime chunk instead of mounting them on __rspack_context
import those lexical bindings from runtime chunks at ESM library render/link sites, including setter helpers such as __rspack_set_*
refresh runtime-mode ESM output snapshots

Context

This is stacked on #14740. The base PR only enables the RuntimeModeEsmOutput context import coverage and fixes modern ESM chunk loading. This PR contains the lexical runtime-global export/import behavior needed for tree shaking when downstream consumers depend on the ESM output runtime chunk.

The behavior is scoped to output module builds using Rspack runtime mode with a split modern-module runtime chunk.

Checks

pnpm run build:binding:dev
pnpm run test:unit

github-actions · 2026-07-09T12:19:51Z

📦 Binary Size-limit

Comparing 5a7c1f7 to fix: preserve createRequire().resolve with literal import.meta.url when requireResolve is disabled (#14783) by Fy

❌ Size increased by 73.25KB from 66.58MB to 66.65MB (⬆️0.11%)

github-actions · 2026-07-10T03:30:26Z

Rsdoctor Bundle Diff Analysis

Found 5 projects in monorepo, 5 projects with changes.

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Project	Total Size	Gzip Size	Change	Gzip Change
popular-libs	1.7 MB	551.5 KB	-	-
react-10k	5.6 MB	1.3 MB	-	-
react-5k	2.7 MB	663.8 KB	-	-
react-1k	823.1 KB	217.0 KB	-	-
ui-components	4.9 MB	1.4 MB	-	-

📋 Detailed Reports (Click to expand)

📁 popular-libs

Path: ../build-tools-performance/cases/popular-libs/dist/rsdoctor-data.json

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Metric	Current	Baseline	Change
📊 Total Size	1.7 MB	-	-
🗜️ Gzip Size	551.5 KB	-	-
📄 JavaScript	1.7 MB	-	-
🎨 CSS	0 B	-	-
🌐 HTML	289.0 B	-	-
📁 Other Assets	0 B	-	-

📁 react-10k

Path: ../build-tools-performance/cases/react-10k/dist/rsdoctor-data.json

⚠️ No baseline data found - Unable to perform comparison analysis

Metric	Current	Baseline	Change
📊 Total Size	5.6 MB	-	-
🗜️ Gzip Size	1.3 MB	-	-
📄 JavaScript	5.6 MB	-	-
🎨 CSS	21.0 B	-	-
🌐 HTML	328.0 B	-	-
📁 Other Assets	0 B	-	-

📁 react-5k

Path: ../build-tools-performance/cases/react-5k/dist/rsdoctor-data.json

⚠️ No baseline data found - Unable to perform comparison analysis

Metric	Current	Baseline	Change
📊 Total Size	2.7 MB	-	-
🗜️ Gzip Size	663.8 KB	-	-
📄 JavaScript	2.7 MB	-	-
🎨 CSS	21.0 B	-	-
🌐 HTML	328.0 B	-	-
📁 Other Assets	0 B	-	-

📁 react-1k

Path: ../build-tools-performance/cases/react-1k/dist/rsdoctor-data.json

⚠️ No baseline data found - Unable to perform comparison analysis

Metric	Current	Baseline	Change
📊 Total Size	823.1 KB	-	-
🗜️ Gzip Size	217.0 KB	-	-
📄 JavaScript	822.7 KB	-	-
🎨 CSS	0 B	-	-
🌐 HTML	328.0 B	-	-
📁 Other Assets	0 B	-	-

📁 ui-components

Path: ../build-tools-performance/cases/ui-components/dist/rsdoctor-data.json

⚠️ No baseline data found - Unable to perform comparison analysis

Metric	Current	Baseline	Change
📊 Total Size	4.9 MB	-	-
🗜️ Gzip Size	1.4 MB	-	-
📄 JavaScript	4.8 MB	-	-
🎨 CSS	112.1 KB	-	-
🌐 HTML	328.0 B	-	-
📁 Other Assets	0 B	-	-

Generated by Rsdoctor GitHub Action

codspeed-hq · 2026-07-13T14:40:22Z

Merging this PR will not alter performance

✅ 43 untouched benchmarks
⏩ 47 skipped benchmarks¹

_{Comparing seal/stacked-lexical-runtime-globals (5a7c1f7) with main (b8e3594)}

47 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

…runtime-globals

…runtime-globals # Conflicts: # tests/rspack-test/esmOutputCases/create-require/import-meta-url-resolve/__snapshots__/runtimeModeSnapshot/esm.snap.txt

Copilot

Pull request overview

This PR refactors Rspack “runtime mode” ESM output to export/import runtime globals as lexical bindings from the runtime chunk (instead of mounting them on __rspack_context), enabling better tree-shaking for downstream consumers when using split modern-module runtime chunks. It also introduces a systematic way to pre-reserve runtime-module-local variable names (derived from EJS templates) to prevent name collisions with user modules, and refreshes runtime-mode ESM snapshots accordingly.

Changes:

Switch runtime-mode ESM output from __rspack_context.* access to direct lexical imports/exports (e.g. rspackRequire, moduleFactories, definePropertyGetters, makeNamespaceObject, etc.).
Add “runtime module variable” extraction/registration (via EJS var() / fn() helpers + inventory registration) to reserve identifiers before runtime module instantiation and avoid userland naming conflicts.
Update runtime EJS templates and a large set of runtime-mode ESM output snapshots; add/adjust targeted test cases for collision and runtimeChunk=false scenarios.

Reviewed changes

Copilot reviewed 200 out of 202 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
crates/rspack_plugin_runtime/src/runtime_module/utils.rs	Allow HMR runtime-state rendering in the new export-based render mode.
crates/rspack_plugin_runtime/src/runtime_module/startup_chunk_dependencies.rs	Add runtime-module-variable extraction and stable template reuse for startup-chunk dependencies runtime module.
crates/rspack_plugin_runtime/src/runtime_module/runtime/startup_chunk_dependencies.ejs	Convert top-level declaration to EJS `var()` to support identifier reservation/deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/require_chunk_loading.ejs	Convert top-level `var` declaration to EJS `var()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/require_chunk_loading_with_hmr.ejs	Convert top-level function declaration to EJS `fn()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/readfile_chunk_loading.ejs	Convert top-level `var` declaration to EJS `var()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/readfile_chunk_loading_with_hmr.ejs	Convert top-level function declaration to EJS `fn()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/on_chunk_loaded.ejs	Convert top-level `var` declaration to EJS `var()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/module_chunk_loading.ejs	Convert top-level `var` declaration to EJS `var()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/module_chunk_loading_with_hmr.ejs	Convert top-level function declaration to EJS `fn()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/load_script.ejs	Convert top-level `var` declaration to EJS `var()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/jsonp_chunk_loading_with_hmr.ejs	Convert top-level vars/functions to EJS `var()` / `fn()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/jsonp_chunk_loading_with_callback.ejs	Convert top-level vars to EJS `var()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/javascript_hot_module_replacement.ejs	Convert top-level vars/functions to EJS `var()` / `fn()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/import_scripts_chunk_loading.ejs	Convert top-level vars to EJS `var()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/import_scripts_chunk_loading_with_hmr.ejs	Convert top-level function to EJS `fn()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/get_trusted_types_policy.ejs	Convert top-level `var` to EJS `var()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/create_fake_namespace_object.ejs	Convert top-level vars to EJS `var()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/chunk_preload_trigger.ejs	Convert top-level `var` to EJS `var()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/chunk_prefetch_trigger.ejs	Convert top-level `var` to EJS `var()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/runtime/auto_public_path.ejs	Convert top-level vars to EJS `var()` for deconfliction.
crates/rspack_plugin_runtime/src/runtime_module/require_js_chunk_loading.rs	Register runtime-module variables extracted from templates; reserve additional internal vars.
crates/rspack_plugin_runtime/src/runtime_module/readfile_chunk_loading.rs	Register runtime-module variables extracted from templates; reserve additional internal vars.
crates/rspack_plugin_runtime/src/runtime_module/on_chunk_loaded.rs	Register runtime-module variables and reuse template string constant.
crates/rspack_plugin_runtime/src/runtime_module/load_script.rs	Register runtime-module variables; reserve additional internal vars.
crates/rspack_plugin_runtime/src/runtime_module/jsonp_chunk_loading.rs	Register runtime-module variables; reserve additional internal vars.
crates/rspack_plugin_runtime/src/runtime_module/get_trusted_types_policy.rs	Register runtime-module variables and reuse template string constant.
crates/rspack_plugin_runtime/src/runtime_module/export_require.rs	Register runtime-module variables for temp export names used by the module.
crates/rspack_plugin_runtime/src/runtime_module/create_fake_namespace_object.rs	Register runtime-module variables extracted from the EJS template.
crates/rspack_plugin_runtime/src/runtime_module/chunk_preload_trigger.rs	Register runtime-module variables extracted from the EJS template.
crates/rspack_plugin_runtime/src/runtime_module/chunk_prefetch_trigger.rs	Register runtime-module variables extracted from the EJS template.
crates/rspack_plugin_runtime/src/runtime_module/auto_public_path.rs	Register runtime-module variables extracted from the EJS template.
crates/rspack_plugin_runtime/src/runtime_module/async_module.rs	Register runtime-module variables and treat export render mode as lexical-capable.
crates/rspack_plugin_runtime/src/helpers.rs	Add extraction of runtime-module variable names from EJS `var()`/`fn()` usage + unit test.
crates/rspack_plugin_mf/src/sharing/share_runtime_module.rs	Register runtime-module variables extracted from sharing EJS template.
crates/rspack_plugin_mf/src/sharing/initializeSharing.ejs	Convert top-level `var` declarations to EJS `var()` for deconfliction.
crates/rspack_plugin_mf/src/sharing/consume_shared_runtime_module.rs	Register runtime-module variables extracted from multiple consume-sharing templates.
crates/rspack_plugin_mf/src/container/embed_federation_runtime_module.rs	Register runtime-module variables extracted from federation embed templates; reuse template constants.
crates/rspack_plugin_mf/src/container/embed_federation_runtime_sync.ejs	Convert top-level `var` declarations to EJS `var()` for deconfliction.
crates/rspack_plugin_mf/src/container/embed_federation_runtime_async.ejs	Convert top-level `var` declarations to EJS `var()` for deconfliction.
crates/rspack_plugin_hmr/src/hot_module_replacement.rs	Register runtime-module variables extracted from HMR EJS template.
crates/rspack_plugin_extract_css/src/runtime/css_loading.ejs	Convert top-level declarations to EJS `var()`; adjust to use `_get_chunk_css_filename` helper variable.
crates/rspack_plugin_extract_css/src/runtime/css_loading_with_preload_link.ejs	Switch to `_get_chunk_css_filename` for CSS href generation.
crates/rspack_plugin_extract_css/src/runtime/css_loading_with_prefetch_link.ejs	Switch to `_get_chunk_css_filename` for CSS href generation.
crates/rspack_plugin_extract_css/src/runtime/css_loading_with_loading.ejs	Convert `installedCssChunks` to EJS `var()` for deconfliction.
crates/rspack_plugin_extract_css/src/runtime/css_loading_with_hmr.ejs	Convert top-level vars to EJS `var()`; switch to `_get_chunk_css_filename`.
crates/rspack_plugin_extract_css/src/plugin.rs	Use a custom export-global name for mini-css chunk filename under export render mode.
crates/rspack_plugin_esm_library/src/runtime.rs	Register runtime-module variables for ESM chunk loading runtime module.
crates/rspack_plugin_esm_library/src/render/runtime_mode/webpack.rs	Add a dedicated webpack-mode runtime renderer for ESM library runtime-mode output.
crates/rspack_plugin_css/src/runtime/mod.rs	Register runtime-module variables extracted from CSS runtime templates; reserve internal var.
crates/rspack_plugin_css/src/runtime/css_loading.ejs	Convert top-level declarations to EJS `var()`/`fn()` for deconfliction.
crates/rspack_plugin_css/src/runtime/css_loading_with_style.ejs	Convert top-level functions/vars to EJS `fn()`/`var()` for deconfliction.
crates/rspack_plugin_css/src/runtime/css_loading_with_hmr.ejs	Convert top-level vars to EJS `var()` for deconfliction.
crates/rspack_macros/src/runtime_module.rs	Extend `#[impl_runtime_module]` macro to optionally register runtime-module-variable providers via `inventory`.
crates/rspack_core/src/runtime_module.rs	Add runtime-module-variable provider plumbing (`inventory` collection + iterator).
crates/rspack_core/src/runtime_globals.rs	Add Rspack-export runtime variable naming and setter-name helper generation.
crates/rspack_core/src/lib.rs	Re-export `inventory` for macro-generated registrations.
crates/rspack_core/src/dependency/mod.rs	Export write-operation type used by runtime requirements dependency templates.
crates/rspack_core/src/compilation/build_module_graph/graph_updater/repair/context.rs	Ensure `runtime_template` is initialized during compilation repair context setup.
crates/rspack_core/src/artifacts/runtime_proxy_metadata_artifact.rs	Generalize lexical declaration rendering to allow name-mapping injection.
crates/rspack_core/Cargo.toml	Add `inventory` dependency for runtime-module-variable registration.
Cargo.lock	Lockfile update for new `inventory` dependency usage.
crates/rspack_plugin_javascript/src/runtime.rs	Export `should_export_rspack_runtime_globals` from runtime context.
crates/rspack_plugin_javascript/src/parser_plugin/import_meta_plugin.rs	Adjust import-meta assignment handling to propagate assignment op + rhs span into helper.
tests/rspack-test/esmOutputCases//snapshots**/runtimeModeSnapshot/esm.snap.txt	Refresh runtime-mode ESM output snapshots to reflect lexical runtime-global exports/imports.
tests/rspack-test/esmOutputCases/basic/split-runtime-chunk/index.js	Add assertion around publicPath mutation behavior when splitting runtime chunk.
tests/rspack-test/esmOutputCases/basic/split-runtime-chunk/snapshots/esm.snap.txt	Refresh baseline (non-runtime-mode) snapshot to include publicPath mutation expectations.
tests/rspack-test/esmOutputCases/interop/runtime-module-variable-conflict/rspack.config.js	New test config to exercise runtime module variable name deconfliction.
tests/rspack-test/esmOutputCases/interop/runtime-module-variable-conflict/index.js	New test asserting userland bindings don’t conflict with runtime module variables.
tests/rspack-test/esmOutputCases/interop/runtime-module-variable-conflict/foo.mjs	New fixture module for the conflict test case.
tests/rspack-test/esmOutputCases/dynamic-import/import-cjs-runtime-chunk-false-entry-export/test.config.js	New test assertions ensuring runtimeChunk=false output doesn’t export rspack runtime globals.
tests/rspack-test/esmOutputCases/dynamic-import/import-cjs-runtime-chunk-false-async-chunk/test.config.js	Update expectations for runtime-mode ESM output to use lexical imports/exports and avoid re-exporting runtime bindings.
tests/rspack-test/esmOutputCases/basic/runtime-chunk-false/test.config.js	New test assertions ensuring runtimeChunk=false runtime-mode output avoids exporting `__rspack_*` globals.
tests/rspack-test/configCases//snapshot*/runtimeModeSnapshot/.txt	Refresh runtime-mode snapshots for config cases impacted by the new lexical runtime-global rendering.

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chatgpt-codex-connector · 2026-07-16T03:56:43Z

+      sources.add(RawStringSource::from(render_rspack_runtime_exports(
+        context_fields,
+        context_fields.intersection(setters),


Emit setters for module-only runtime writes

In RspackExport mode, render_runtime_global_specifiers imports setter helpers for every module write recorded in CodeGenerationRuntimeRequirementsWrite, but this call only emits a setter when the same runtime global is also present in a runtime module's define/force_context fields. For globals such as SCRIPT_NONCE (e.g. import.meta.rspackNonce = "n" or __webpack_require__.nc = "n") there is no defining runtime module, so a split modern-module runtime chunk declares no setScriptNonce export while the entry chunk imports/calls it, causing the ESM module to fail during linking.

Useful? React with 👍 / 👎.

Base automatically changed from seal/lexical-runtime-exports to main July 10, 2026 03:52

LingyuCoder changed the title ~~fix: export lexical runtime globals for esm chunks~~ refactor: export lexical runtime globals for esm chunks Jul 13, 2026

LingyuCoder changed the base branch from main to seal/runtime-template-render-modes July 13, 2026 11:45

LingyuCoder force-pushed the seal/runtime-template-render-modes branch from aa258ea to 0af5acb Compare July 13, 2026 13:39

LingyuCoder force-pushed the seal/stacked-lexical-runtime-globals branch from 2dbde1d to 40f063b Compare July 13, 2026 14:20

Base automatically changed from seal/runtime-template-render-modes to main July 14, 2026 04:52

LingyuCoder added 2 commits July 14, 2026 13:58

refactor: export lexical runtime globals for esm chunks

9e4c583

refactor: split esm runtime renderers by mode

afc24cb

LingyuCoder force-pushed the seal/stacked-lexical-runtime-globals branch from 40f063b to afc24cb Compare July 14, 2026 06:10

LingyuCoder added 7 commits July 14, 2026 16:24

fix: reserve runtime module variables in esm output

af60153

Merge remote-tracking branch 'origin/main' into seal/stacked-lexical-…

ef50372

…runtime-globals

refactor: use semantic names for exported runtime bindings

cbdc92d

Merge remote-tracking branch 'origin/main' into seal/stacked-lexical-…

bf0ef18

…runtime-globals

fix: optimize runtime variable registration

9e75f3a

refactor: collect runtime module variables from ejs

abcb3b0

Merge remote-tracking branch 'origin/main' into seal/stacked-lexical-…

5a7c1f7

…runtime-globals # Conflicts: # tests/rspack-test/esmOutputCases/create-require/import-meta-url-resolve/__snapshots__/runtimeModeSnapshot/esm.snap.txt

LingyuCoder marked this pull request as ready for review July 16, 2026 03:48

LingyuCoder requested a review from ahabhgk as a code owner July 16, 2026 03:48

Copilot AI review requested due to automatic review settings July 16, 2026 03:48

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refactor: export lexical runtime globals for esm chunks#14741

refactor: export lexical runtime globals for esm chunks#14741
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📁 popular-libs

📁 react-10k

📁 react-5k

📁 react-1k

📁 ui-components

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LingyuCoder commented Jul 9, 2026

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Rsdoctor Bundle Diff Analysis

📁 popular-libs

📁 react-10k

📁 react-5k

📁 react-1k

📁 ui-components

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Merging this PR will not alter performance

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