Generate source maps by default for Vite plugin Workers and Build Output by WalshyDev · Pull Request #16245 · cloudflare/workers-sdk

WalshyDev · 2026-10-13T15:46:02Z

Follow-up to #16231, which turned source map uploads on by default for wrangler deploy, wrangler versions upload and wrangler preview. Two build paths still don't produce source maps by default, so there's nothing to upload from them. One of those is the path cf uses.

Vite plugin: Vite leaves build.sourcemap off by default, so Worker builds never emitted maps. Worker environments now default it to true unless the user sets build.sourcemap (per environment or at the top level) or sets upload_source_maps in the Worker config. The client environment isn't affected, so no maps end up in public assets.
wrangler build --experimental-cf-build-output (and the cf-wrangler build delegate): only included source maps when upload_source_maps = true. It now uses the same default as deploy. Maps it can't resolve are skipped instead of failing the build, and upload_source_maps = false opts out.

Tests
- Tests included/updated
- Automated tests not possible - manual testing has been completed as follows:
- Additional testing not necessary because:
Public documentation
- Cloudflare docs PR(s):
- Documentation not necessary because: existing docs that enable build.sourcemap explicitly are still correct; they can be simplified in a follow-up

`wrangler build --experimental-cf-build-output` (and the `cf-wrangler` build delegate used by `cf`) only emitted source maps when `upload_source_maps = true`. It now uses the same best-effort default as `wrangler deploy` and `wrangler versions upload`: source maps are generated and listed in the Build Output manifest, unresolvable ones are skipped, and `upload_source_maps = false` opts out.

Vite leaves `build.sourcemap` off by default, so Worker builds never emitted source maps and neither Build Output nor the generated `wrangler.json` had any to upload. Worker environments now default `build.sourcemap` to `true` unless the user sets it (per-environment or top-level) or sets `upload_source_maps` in the Worker config. Only Worker environments are affected, so no source maps end up in public client assets.

changeset-bot · 2026-10-13T15:46:08Z

🦋 Changeset detected

Latest commit: 5d108f6

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 3 packages

Name	Type
wrangler	Minor
@cloudflare/vite-plugin	Minor
@cloudflare/vitest-plugin	Patch

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workers-devprod · 2026-10-13T15:46:36Z

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pkg-pr-new · 2026-10-13T15:49:32Z

@cloudflare/autoconfig

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@cloudflare/build-output-utils

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@cloudflare/kv-asset-handler

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miniflare

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@cloudflare/vite-plugin

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@cloudflare/vitest-plugin

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@cloudflare/workers-auth

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@cloudflare/workers-editor-shared

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wrangler

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commit: 5d108f6

ask-bonk · 2026-10-13T15:50:45Z

LGTM!

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workers-devprod

Codeowners reviews satisfied

## pnpm-workspace.yaml (default) ## Dependency Updates | Package | From | To | Type | | --- | --- | --- | --- | | `wrangler` | 4.150.0 | 4.151.0 | minor | ## Release Notes <details> <summary><b>wrangler</b> (4.150.0 → 4.151.0)</summary> ### Minor Changes - [#16245](cloudflare/workers-sdk#16245) [`d6b1c82`](cloudflare/workers-sdk@d6b1c82) Thanks [@WalshyDev](https://github.com/WalshyDev)! - Include source maps by default in `wrangler build --experimental-cf-build-output` Build Output now matches `wrangler deploy` and `wrangler versions upload`, which upload source maps by default, so Workers built for tools like `cf` get stack traces that point at the original source. Source maps that can't be resolved are skipped rather than failing the build. Set `upload_source_maps = false` to opt out. ### Patch Changes - [#16220](cloudflare/workers-sdk#16220) [`97b2fb1`](cloudflare/workers-sdk@97b2fb1) Thanks [@FlorentCollin](https://github.com/FlorentCollin)! - Support local D1 queries through the experimental `d1_binding_jsrpc` compatibility flag Local D1 bindings now implement the RPC query backend used by `D1Database.query()` and prepared-statement methods when the flag is enabled. Queries reuse local SQLite execution, including transactional batches, execution metadata, and session bookmarks, while bindings without the flag continue to use HTTP. Update the bundled workerd runtime to `1.20261012.1` and align the default compatibility date with that release. - Updated dependencies [[`f360829`](cloudflare/workers-sdk@f360829), [`97b2fb1`](cloudflare/workers-sdk@97b2fb1), [`97b2fb1`](cloudflare/workers-sdk@97b2fb1), [`acd2822`](cloudflare/workers-sdk@acd2822)]: - miniflare@5.20261012.0-beta </details> --- *This PR was auto-generated by [catalog-update-action](https://github.com/brandhaug/catalog-update-action).* Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>

Wrangler now generates and uploads source maps by default for `wrangler deploy`, `wrangler versions upload` and `wrangler preview` (cloudflare/workers-sdk#16231). The Cloudflare Vite plugin and Wrangler's Build Output now also generate source maps by default (cloudflare/workers-sdk#16245), so `cf deploy`, which uploads every source map in the build output, gets them without configuration too. Update the source maps, configuration and cf migration docs to describe the new defaults, the lenient handling of unresolvable maps, and how to opt out with Wrangler and with cf, and add a changelog entry announcing it.

…34245) Wrangler now generates and uploads source maps by default for `wrangler deploy`, `wrangler versions upload` and `wrangler preview` (cloudflare/workers-sdk#16231). The Cloudflare Vite plugin and Wrangler's Build Output now also generate source maps by default (cloudflare/workers-sdk#16245), so `cf deploy`, which uploads every source map in the build output, gets them without configuration too. Update the source maps, configuration and cf migration docs to describe the new defaults, the lenient handling of unresolvable maps, and how to opt out with Wrangler and with cf, and add a changelog entry announcing it.

WalshyDev added 2 commits October 13, 2026 11:25

WalshyDev requested a review from workers-devprod as a code owner October 13, 2026 15:46

workers-devprod added this to workers-sdk Oct 13, 2026

github-project-automation Bot moved this to Untriaged in workers-sdk Oct 13, 2026

workers-devprod requested review from a team and jamesopstad and removed request for a team October 13, 2026 15:46

devin-ai-integration Bot reviewed Oct 13, 2026

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dario-piotrowicz requested review from dario-piotrowicz and removed request for jamesopstad October 13, 2026 15:51

dario-piotrowicz approved these changes Oct 13, 2026

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workers-devprod approved these changes Oct 13, 2026

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github-project-automation Bot moved this from Untriaged to Approved in workers-sdk Oct 13, 2026

WalshyDev enabled auto-merge (squash) October 13, 2026 16:06

WalshyDev merged commit d6b1c82 into main Oct 13, 2026
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WalshyDev deleted the walshy/build-output-source-maps branch October 13, 2026 16:06

github-project-automation Bot moved this from Approved to Done in workers-sdk Oct 13, 2026

workers-devprod mentioned this pull request Oct 13, 2026

Version Packages #16241

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brandhaug mentioned this pull request Oct 17, 2026

chore(deps): bump wrangler from 4.150.0 to 4.151.0 brandhaug/b2b-saas-starter#1328

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mayesidev mentioned this pull request Oct 18, 2026

chore(deps): update cloudflare development toolchain mayesidev/ludovico-tech#386

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WalshyDev mentioned this pull request Oct 19, 2026

[Workers] Document source maps being uploaded by default cloudflare/cloudflare-docs#34245

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github-actions Bot mentioned this pull request Oct 21, 2026

chore(deps): update dependency wrangler to v4.151.0 lacolaco/blog.lacolaco.net#2193

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Generate source maps by default for Vite plugin Workers and Build Output - #16245

Generate source maps by default for Vite plugin Workers and Build Output#16245
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