[wrangler] Upload source maps by default by WalshyDev · Pull Request #16231 · cloudflare/workers-sdk

WalshyDev · 2026-10-12T20:57:22Z

Fixes #[insert GH or internal issue link(s)].

upload_source_maps now defaults to on for wrangler deploy, wrangler versions upload and wrangler preview when it isn't set in config or via --upload-source-maps, so stack traces point at original source without extra setup. wrangler build --experimental-cf-build-output keeps its opt-in behaviour.

When defaulted, source maps that can't be resolved (inline data: maps, missing .map files from custom builds) are skipped with a debug log instead of failing the upload, so existing prebuilt Workers keep deploying. An explicit upload_source_maps = true keeps the strict errors, and false / --no-upload-source-maps opts out.

Also fixes Wrangler-bundled source map path resolution on Windows when --outdir is on a different drive; esbuild reports an absolute path there, which was previously joined onto the entry directory.

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): [Workers] Document source maps being uploaded by default cloudflare-docs#34245
- Documentation not necessary because:

changeset-bot · 2026-10-12T20:57:28Z

🦋 Changeset detected

Latest commit: fa5e9cf

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	Patch
@cloudflare/vitest-plugin	Patch

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ask-bonk · 2026-10-12T21:00:49Z

P2: Preserve the opt-in behavior of other buildWorker consumers.

The new undefined default applies to Preview and wrangler build --experimental-cf-build-output too, although this PR only scopes the default to deploy and versions upload. Preview therefore uploads maps without configuration, while Build Output emits map modules even though it does not upload a Worker.

packages/wrangler/src/preview/preview.ts:110

				uploadSourceMaps: previewConfig.upload_source_maps ?? false,

packages/wrangler/src/deployment-bundle/merge-config-args.ts:256

		uploadSourceMaps: config.upload_source_maps ?? false,

ask-bonk · 2026-10-12T21:00:54Z

I'm Bonk, and I've done a quick review of your PR.

Defaults source-map generation and uploads for deploys and versions uploads.

P2: The shared default also changes Preview and experimental Build Output behavior. Posted a suggestion comment covering both call sites.

github run

pkg-pr-new · 2026-10-12T21:01:21Z

@cloudflare/autoconfig

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@cloudflare/containers-shared

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create-cloudflare

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@cloudflare/kv-asset-handler

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miniflare

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@cloudflare/pages-functions

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@cloudflare/pages-shared

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@cloudflare/runtime-types

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@cloudflare/unenv-preset

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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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@cloudflare/workers-utils

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wrangler

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commit: fa5e9cf

workers-devprod · 2026-10-13T01:00:08Z

Codeowners approval required for this PR:

✅ @cloudflare/wrangler

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`upload_source_maps` now defaults to on for `wrangler deploy`, `wrangler versions upload` and `wrangler preview` when it isn't set in config or via `--upload-source-maps`, so stack traces point at original source without extra setup. `wrangler build --experimental-cf-build-output` keeps its opt-in behaviour. When defaulted, source maps that can't be resolved (inline `data:` maps, missing `.map` files from custom builds) are skipped with a debug log instead of failing the upload, so existing prebuilt Workers keep deploying. An explicit `upload_source_maps = true` keeps the strict errors, and `false` / `--no-upload-source-maps` opts out. Also resolve Wrangler-bundled source map paths with `path.resolve`, as esbuild reports an absolute output path when `--outdir` is on a different Windows drive, which previously produced an invalid joined path.

workers-devprod

Codeowners reviews satisfied

Wrangler now generates and uploads source maps by default for `wrangler deploy`, `wrangler versions upload` and `wrangler preview` (cloudflare/workers-sdk#16231). Update the source maps and configuration docs to describe the new default, the lenient handling of unresolvable maps, and how to opt out, and add a changelog entry announcing it.

## pnpm-workspace.yaml (default) ## Dependency Updates | Package | From | To | Type | | --- | --- | --- | --- | | `wrangler` | 4.149.0 | 4.150.0 | minor | ## Release Notes <details> <summary><b>wrangler</b> (4.149.0 → 4.150.0)</summary> ### Minor Changes - [#16231](cloudflare/workers-sdk#16231) [`091e5ec`](cloudflare/workers-sdk@091e5ec) Thanks [@WalshyDev](https://github.com/WalshyDev)! - Upload source maps by default for `wrangler deploy`, `wrangler versions upload` and `wrangler preview` When `upload_source_maps` isn't set in config or via `--upload-source-maps`, Wrangler now generates and uploads source maps so stack traces in logs and `wrangler tail` point at your original source without extra setup. In this default mode, source maps that can't be resolved (for example inline `data:` maps or missing `.map` files from a custom build) are skipped rather than failing the upload. Setting `upload_source_maps = true` keeps the existing strict behaviour, and `upload_source_maps = false` (or `--no-upload-source-maps` for deploy and versions upload) opts out. `wrangler build --experimental-cf-build-output` is unchanged and still only includes source maps when `upload_source_maps = true`. - [#16128](cloudflare/workers-sdk#16128) [`daae435`](cloudflare/workers-sdk@daae435) Thanks [@redsteadz](https://github.com/redsteadz)! - Stop `wrangler deploy`, `wrangler versions upload` and `wrangler preview` in projects that build for the Cloudflare CLI (`cf`) If your project builds through `cf`, deploying it with Wrangler reads a different configuration, so it could update the wrong Worker or fail without explaining why. These commands now stop before uploading anything, name the `.cloudflare/output` directory they found, and tell you to run `cf deploy` instead. If that directory is just left over from an earlier build, deleting it restores the Wrangler workflow. Ordinary Wrangler projects are unaffected, and `--dry-run` still works on `deploy` and `versions upload`. This is a new guard for the experimental Build Output Specification rat …[full notes](https://github.com/cloudflare/workers-sdk/releases/tag/wrangler%404.150.0) </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.

workers-devprod added this to workers-sdk Oct 12, 2026

github-project-automation Bot moved this to Untriaged in workers-sdk Oct 12, 2026

WalshyDev force-pushed the walshy/default-upload-source-maps branch from 0478c2c to eb976df Compare October 13, 2026 00:42

WalshyDev marked this pull request as ready for review October 13, 2026 00:59

WalshyDev requested a review from workers-devprod as a code owner October 13, 2026 00:59

WalshyDev force-pushed the walshy/default-upload-source-maps branch from eb976df to 83dc0c3 Compare October 13, 2026 00:59

workers-devprod requested review from a team and petebacondarwin and removed request for a team October 13, 2026 01:00

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WalshyDev force-pushed the walshy/default-upload-source-maps branch from 83dc0c3 to 32c878a Compare October 13, 2026 01:04

WalshyDev force-pushed the walshy/default-upload-source-maps branch from 32c878a to fa5e9cf Compare October 13, 2026 01:06

WalshyDev mentioned this pull request Oct 13, 2026

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

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petebacondarwin enabled auto-merge (squash) October 13, 2026 06:40

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petebacondarwin merged commit 091e5ec into main Oct 13, 2026
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workers-devprod mentioned this pull request Oct 13, 2026

Version Packages #16162

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WalshyDev mentioned this pull request Oct 13, 2026

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

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brandhaug mentioned this pull request Oct 16, 2026

chore(deps): bump wrangler from 4.149.0 to 4.150.0 brandhaug/b2b-saas-starter#1299

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chore(deps): update frontend devdependencies kpool09122/kpool-frontend#470

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github-actions Bot mentioned this pull request Oct 18, 2026

chore(deps): update dependency wrangler to v4.150.0 lacolaco/blog.lacolaco.net#2160

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oddharsh mentioned this pull request Oct 19, 2026

chore(deps): dependency leverage digest oddharsh/site#1144

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[wrangler] Upload source maps by default - #16231

[wrangler] Upload source maps by default#16231
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