UI: Load Monaco workers via a same-origin Blob shim (fix dev-mode noise)#67352
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Merge #67316 first |
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In dev mode the SPA shell is served by the airflow api-server while Vite serves assets on a different origin. Module workers cannot be constructed cross-origin even when CORS allows the fetch — Chrome refuses with 'Script at <vite url> cannot be accessed from origin <api-server>'. Monaco then falls back to 'main-thread workers', whose `$loadForeignModule` path tries to resolve module IDs through the non-existent AMD `require.toUrl`, flooding the console with `Cannot read properties of undefined (reading 'toUrl')` errors. Swap the `?worker` constructor imports for `?url` imports and construct workers from a same-origin Blob shim that simply re-imports the resolved URL. The Blob lives on the page origin so the Worker constructor accepts it, and the inner cross-origin `import` is permitted by Vite's CORS response. Closes apache#67342.
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Stacked on top of #67316 only last commit is relevant
What this fixes
#67342: in dev mode the browser console fills with
```
TypeError: Cannot read properties of undefined (reading 'toUrl')
at FileAccessImpl.toUri (...)
at EditorSimpleWorker.$loadForeignModule (...)
```
every time a Monaco editor mounts (XComs, Audit Log, DAG code, ...).
Production builds are unaffected; this is dev-mode only.
Why
In dev mode the SPA shell is served by the airflow api-server while
Vite serves assets on a different origin. Vite's `?worker` import
generates `new Worker(crossOriginUrl, { type: "module" })` which the
browser refuses for cross-origin module workers — `server.cors` does
not help here, the Worker constructor itself rejects it ('Script at
cannot be accessed from origin '). Monaco then
falls back to 'main-thread workers'; that fallback path executes
`$loadForeignModule` synchronously and resolves module IDs through the
non-existent AMD `require.toUrl`, throwing repeatedly.
Fix
Swap the `?worker` constructor imports for `?url` imports and build
workers from a same-origin Blob shim that simply re-imports the
resolved URL. The Blob URL lives on the page origin so the Worker
constructor accepts it, and the inner cross-origin `import` is allowed
by Vite's CORS response.
Closes #67342
Screen.Recording.2026-05-22.at.19.27.11.mov
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