[wrangler] Support source phase imports

[guybedford]

Fixes #12995.

Wrangler's shared esbuild config targeted es2024 without enabling source phase import syntax, which caused import source Wasm imports to fail before Wrangler could preserve them in deploy output.

This enables esbuild's import-source syntax support in Wrangler's shared build options so source phase Wasm imports work in both bundled and --no-bundle deploy paths. It also adds regression coverage for worker format detection, wrangler deploy --no-bundle --dry-run, and bundled deploy output written via --outdir and --outfile.

---

• 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: this fixes Wrangler's handling of an existing Wasm import syntax without changing the documented API.

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[changeset-bot]

🦋 Changeset detected

Latest commit: ef02bad

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[workers-devprod]

Codeowners approval required for this PR:

• @cloudflare/wrangler

Show detailed file reviewers

• packages/wrangler/src/tests/deploy/build.test.ts: [@cloudflare/wrangler]
• packages/wrangler/src/tests/deploy/formats.test.ts: [@cloudflare/wrangler]
• packages/wrangler/src/tests/guess-worker-format.test.ts: [@cloudflare/wrangler]
• packages/wrangler/src/deployment-bundle/bundle.ts: [@cloudflare/wrangler]

[github-actions]

✅ All changesets look good

[ask-bonk]

The review is complete. Let me analyze the changes:

1. COMMON_ESBUILD_OPTIONS at bundle.ts:49 adds supported: { "import-source": true } — this tells esbuild to recognize source phase import syntax.

2. guess-worker-format.ts:27 already spreads ...COMMON_ESBUILD_OPTIONS, so it automatically picks up the new supported field. This fixes the format detection path.

3. bundle.ts:388 explicitly passes supported: COMMON_ESBUILD_OPTIONS.supported in the bundleWorker build options. This fixes the --no-bundle deploy path.

4. Tests cover both the format detection path and the --no-bundle --dry-run deploy path.

The fix is correct and minimal:

• guess-worker-format.ts uses spread so it inherits supported automatically — no change needed.
• bundleWorker doesn't spread COMMON_ESBUILD_OPTIONS; it picks fields individually. The PR correctly adds the supported field alongside the existing target and loader references.
• The changeset is properly scoped as a patch to wrangler.
• Tests are well-targeted regression tests.

LGTM

github run

[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 2 additional findings.

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commit: ef02bad