fix(js): load webgpu via dynamic import and fall back to CPU when unavailable - #562
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The CJS build (dist/node/img2num.cjs) crashed on Node < 22.12 instead of
converting. Two causes:
1. src/target/node/webgpu.js statically imported the ESM-only `webgpu`
package. Rolldown compiles static imports of externals in the CJS
output to a top-level require("webgpu"), which throws ERR_REQUIRE_ESM
on Node < 22.12 (Node >= 22.12 supports require(esm), masking the bug
in dev). The import is now dynamic, which Rolldown preserves as a real
import() in CJS output.
2. When the webgpu import rejects (ERR_REQUIRE_ESM, or the optional
dependency not installed, e.g. --ignore-optional), initWasmModule
logged "should fall back to CPU" but initialized the wasm anyway with
no globalThis.navigator. The Emscripten glue dereferences `navigator`
unconditionally, so the conversion died with "navigator is not
defined" instead of falling back. The catch block now installs a stub
navigator.gpu whose requestAdapter() resolves null, routing the glue
to its CPU path.
Adds a generateBundle guard (cjsWebgpuGuard) for the node-cjs target
that fails the build if any emitted chunk contains an executable
require("webgpu"), so a future bundler change cannot silently lower the
dynamic import back into the broken form (same class of regression as
the v0.4.0 wasm URL inlining).
Verified: guard fails the build when the static import is reintroduced;
with node_modules/webgpu removed, both ESM and CJS console examples
fall back to CPU and produce the SVG; with webgpu present, the CJS
entry now initializes the GPU identically to ESM.
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WalkthroughChangesThe WebGPU Node target now dynamically imports the ESM-only package. Failed initialization logs CPU fallback behavior and installs navigator stubs. The WebGPU compatibility
Estimated code review effort: 2 (Simple) | ~10 minutes Merge Risk: 🟡 Moderate · up to The PR changes Node runtime loading and CPU fallback behavior, but the current implementation can delete a pre-existing global navigator during teardown and the build guard can miss an executable require("webgpu") in some emitted code. Either issue can break valid Node applications or allow the original CJS failure through, so merge should wait for these fixes. Possibly related PRs
Suggested labels: Poem
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✨ Finishing Touches 💡 1🛠️ Fix failing CI checks 💡
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Inline comments:
In `@packages/js/src/target/node/webgpu.js`:
- Around line 28-29: Track navigator ownership in the native initialization path
around globalThis.navigator and globalThis.navigator.gpu, and apply the same
policy in packages/js/src/wasmModule.js lines 46-47 for the CPU fallback stub:
record whether the module created navigator, preserve pre-existing navigator
objects, and ensure destroyWebGPU() removes only module-owned state rather than
the whole global.
In `@packages/js/vite.config.js`:
- Around line 98-99: The CJS guard around the chunk code must detect executable
require("webgpu") calls without corrupting JavaScript containing URLs, strings,
regular expressions, or comments. Replace the comment-stripping regex in the
chunk validation logic with a JavaScript-aware tokenizer, parser, or stateful
scanner, and add fixtures covering those cases.
🪄 Autofix
Fix all unresolved CodeRabbit comments on this PR:
- Push a commit to this branch (recommended)
- Create a new PR with the fixes
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📓 Path-based instructions (1)
**/*.{js,ts,jsx,tsx}
📄 CodeRabbit inference engine (.editorconfig)
**/*.{js,ts,jsx,tsx}: Use 2-space indentation for JavaScript and TypeScript files
Maintain 200 character maximum line length for JavaScript/TypeScript files
Files:
packages/js/src/wasmModule.jspackages/js/vite.config.jspackages/js/src/target/node/webgpu.js
🔇 Additional comments (3)
packages/js/src/target/node/webgpu.js (1)
12-16: LGTM!Also applies to: 25-27, 30-31
packages/js/src/wasmModule.js (1)
43-45: LGTM!packages/js/vite.config.js (1)
87-97: LGTM!Also applies to: 100-108, 187-187
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Comment-stripping with a regex mis-lexes double forward-slash nside string literals (URLs) and could hide an executable require of webgpu. The guard now matches raw chunk code; the source JSDoc no longer contains the matchable pattern, so any hit is executable. Addresses CodeRabbit review on the guard's false-negative case.
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…test corpora (#566) The default inclusion mode leaves include/exclude collisions unspecified: sdist.include "third_party/dawn/**" overlapped every Dawn exclude pattern, producing inconsistent tarballs from the same config (35k vs 93k entries across otherwise identical builds). Explicit mode documents that exclude is applied after include, making sdist contents deterministic. Explicit mode also ignores .gitignore, so local build directories are excluded here too. Excludes Dawn's test corpora (~60k files never consumed by any build) whose vk-gl-cts tree caused the deterministic sdist unpack failure in CI (see the Build Python failures on #562), the webgpu-cts GN metadata (43 MB test_list.txt plus an 8 MB cache tarball, both also present in the currently published PyPI sdist), the opt-in HermeticXcode macOS toolchain dir that contains the tree's only dangling symlink, and the dangling dawn/.git submodule gitlink. Result: 105 MB / 93k entries down to 6.5 MB / ~5k entries. The wheel builds from the sdist end-to-end and the console example runs on the GPU path. inclusion-mode = "explicit" requires scikit-build-core >= 1.0, so the build-system floor is bumped accordingly.
The explicit sdist manifest introduced when trimming the Dawn tarball never covered third_party/spdlog, so wheels built from the sdist (the path CI and plain `uv build` take, unlike `uv sync` which builds from the working tree) failed at configure: core's add_subdirectory pointed at a directory absent from the archive. Generalize the third_party excludes to recursive gitwildmatch patterns (**/.git, **/build/, **/test(s)/, ...), replacing the per-path Dawn entries. This also sweeps the nested submodule gitlinks under dawn/third_party that the old excludes never caught. The vk-gl-cts rationale from PR Ryan-Millard#562 still applies; it is now covered by the **/test/ pattern. Add wheel.license-files so the wheel's dist-info carries license texts for the statically linked third-party code (spdlog, Dawn and its vendored dependencies) alongside our own. Verified by building the wheel from the sdist (uv build) and inspecting the archive for spdlog, absence of .git entries, and collected licenses.
1 participant
Problem
require("img2num")on Node 18/20 crashed duringimageToSvg():[Img2Num wasmModule] WebGPU init error: Error [ERR_REQUIRE_ESM]: require() of ES Module .../node_modules/webgpu/index.js from .../img2num/dist/node/webgpu-DnHE7-PM.cjs not supported.
...
Error: [Img2Num wasmClient] Error: navigator is not defined`
Found while building the Node.js CJS example sandbox against the published v0.4.1.
Causes
1.
require()of the ESM-onlywebgpupackage.src/target/node/webgpu.jsused a staticimport { create } from "webgpu". In the node-cjs target, Rolldown compiles static imports of externals to a top-levelrequire("webgpu"). Thewebgpupackage is ESM-only, so this throwsERR_REQUIRE_ESMon Node < 22.12. Node ≥ 22.12 supportsrequire(esm)natively, which is why the bug never reproduced in the dev container (Node 22.16) — ourenginesfield says>=18.2. The CPU fallback didn't fall back.
When the webgpu import rejects (this bug, or the optional dependency simply not installed —
--ignore-optional, unsupported platform),initWasmModulelogged "Img2Num should fall back to CPU" and then initialized the wasm module anyway with noglobalThis.navigator. The Emscripten glue's_emwgpuInstanceRequestAdapterdereferences barenavigator, so the conversion crashed instead of using the CPU.Fixes
src/target/node/webgpu.js: loadwebgpuvia dynamicimport()insideinitWebGPU(). Rolldown preserves it as a genuineimport()in the CJS output, which can load ESM from CJS on all supported Node versions.src/wasmModule.js: on webgpu init failure, install a stubnavigator.gpuwhoserequestAdapter()resolvesnull. The glue's adapter probe then fails cleanly and the CPU path engages — same flow as a GPU-less machine with webgpu installed.vite.config.js: newcjsWebgpuGuardplugin (node-cjs target only) fails the build ingenerateBundleif any emitted chunk contains an executablerequire("webgpu")(comments stripped before matching). This is the same guard pattern aswasmUrlPlugin: the failure mode is the bundler rewriting load-bearing code during emit, which no source-level check can catch — see the v0.4.0 wasm URL inlining regression.Verification
pnpm build:node-cjsfail with the guard error. Clean build passes all four targets. (Note:emptyOutDir: falseon node-cjs means the guard also scans stale chunks indist/node/— runjust clean packages-jsif it flags a hash that no longer builds.)node_modules/webgpuremoved,just console-js-esmandjust console-js-cjsboth print "Falling back to CPU", produce the SVG, and exit 0.just console-js-cjsnow initializes the adapter/device identically to the ESM entry.import("webgpu")and no executablerequire("webgpu").Out of scope
On machines with working Vulkan, both entries crash after successful SVG output during process teardown (nondeterministic: SIGSEGV / pthread_mutex assertion / futex error). This is Dawn teardown racing process exit in the upstream
webgpupackage, pre-exists this change, and only affects the GPU path at exit. Tracked separately.