fix(compiler): resolve emitter options for subpath exports by tanvir-ux · Pull Request #11746 · microsoft/typespec

Tanvir Alam (tanvir-ux) · 2026-08-22T18:35:35Z

loadEmitter() looked up tspconfig options with metadata.name from the parent package.json, so emitters exposed as subpath exports (e.g. @org/pkg/typescript) never matched the key users actually wrote.

Prefer the emit specifier, then fall back to the package name so file emitters and older configs still work.

Fixes #10200

azure-pipelines · 2026-08-22T18:35:56Z

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Pull request overview

This PR fixes @typespec/compiler emitter option resolution when emitters are exposed via subpath exports (e.g. @org/pkg/typescript), by preferring the emitter specifier from tspconfig.yaml/CLI options while retaining backwards compatibility via fallback to the package/library name.

Changes:

Update loadEmitter() to resolve emitter options using the emit specifier first, then fall back to metadata.name.
Add compiler tests covering subpath-export emitters (specifier-keyed options + package-name fallback).
Add a Chronus changelog entry for the compiler fix.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
`packages/compiler/src/core/program.ts`	Adjusts emitter options lookup order to support subpath export specifiers.
`packages/compiler/test/core/emitter-options.test.ts`	Adds regression tests for subpath-export emitter option resolution behavior.
`.chronus/changes/fix-subpath-emitter-options-2026-8-22.md`	Changelog entry documenting the compiler fix.

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Tanvir Alam (tanvir-ux) · 2026-08-22T19:12:00Z

@microsoft-github-policy-service agree

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Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

Suppressed comments (1)

packages/compiler/src/core/program.ts:645

Default emitterOutputDir is still derived from metadata.name (package.json name for module emitters). With multiple subpath-export emitters from the same package, this can route different emitters into the same default output directory unless users explicitly set emitter-output-dir. Consider using the emit specifier for module emitters to avoid collisions.

    if (emitterOutputDir === undefined) {
      emitterOutputDir = [options.outputDir, metadata.name].filter(isDefined).join("/");
    }

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Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

pkg-pr-new · 2026-08-27T12:36:55Z

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npm i https://pkg.pr.new/@typespec/compiler@11746

commit: 2053239

github-actions · 2026-08-27T12:39:18Z

All changed packages have been documented.

✅ @typespec/compiler

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`@typespec/compiler` - fix ✏️

Resolve tspconfig emitter options for packages exposed as subpath exports, and default their output directories to the emit specifier.

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Copilot reviewed 3 out of 3 changed files in this pull request and generated no new comments.

Timothee Guerin (timotheeguerin) · 2026-08-27T16:15:30Z

+    // name for module emitters) for older configs and file-based emitters.
+    const libraryName = metadata.name;
+    let emitterOptionsKey = emitterNameOrPath;
+    if (


i'm not fully sure the solution is at the correct place here. Specially if we decide that each sub emitter will have its own $lib this seems to me like this should have already been resolved in the library loading logic

Agreed this is the awkward layer. computeLibraryMetadata currently always uses the package.json name for modules and ignores $lib.name (that is only used for file emitters). tspconfig options are keyed by the emit specifier, which is why I matched here.

If subpath emitters are each expected to export their own $lib with a unique name, I can move this into loadLibrary / computeLibraryMetadata so metadata.name is $lib.name (fallback package name) and loadEmitter just uses that. Want me to take it that direction, or keep the specifier-first lookup here because configs already use the emit path?

Gentle ping on the direction question above — happy to move the lookup into loadLibrary / computeLibraryMetadata if that is preferred, or keep the specifier-first path here. Just need a steer before I change more.

microsoft-github-policy-service · 2026-09-26T15:24:40Z

Hi @Tanvir Alam (@tanvir-ux). Your PR has had no update for 14 days and it is marked as a stale PR. If it is not updated within 14 additional days, the PR will automatically be closed. If you want to refresh the PR, please remove the stale label.

Prefer the tspconfig emitter specifier when looking up options so packages exposed as subpath exports receive their configured options. Fixes microsoft#10200

Use the emit specifier for module-emitter defaults so sibling subpath exports do not collide, and point option schema diagnostics at the config key that actually supplied the values.

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🔵 Needs a closer look

Add coverage proving subpath options take precedence when both keys are configured.

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Resolved since last review (3)

Default emitterOutputDir uses metadata.name (package.json name). For subpath export emitters,…
The new fallback logic uses metadata.name (which is $lib.name for file emitters, and…
When options fall back to metadata.name (e.g. user configures options["@org/fake-emitter"] but…

Copilot AI lite review requested due to automatic review settings August 22, 2026 18:35

Tanvir Alam (tanvir-ux) requested review from catalinaperalta, iscai-msft, Laurent Mazuel (lmazuel), Mark Cowlishaw (markcowl) and Timothee Guerin (timotheeguerin) as code owners August 22, 2026 18:35

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Copilot AI review requested due to automatic review settings August 27, 2026 12:45

Tanvir Alam (tanvir-ux) force-pushed the fix/subpath-emitter-options branch from f3b62bd to 2053239 Compare August 27, 2026 12:45

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microsoft-github-policy-service Bot added the stale Mark a PR that hasn't been recently updated and will be closed. label Sep 26, 2026

Tanvir Alam (tanvir-ux) added 4 commits October 4, 2026 08:12

fix(compiler): resolve emitter options for subpath exports

861b78a

Prefer the tspconfig emitter specifier when looking up options so packages exposed as subpath exports receive their configured options. Fixes microsoft#10200

Point emitter option diagnostics at the config key that was used.

8ecb466

fix(compiler): unique default output dirs for subpath emitters

ababffa

Use the emit specifier for module-emitter defaults so sibling subpath exports do not collide, and point option schema diagnostics at the config key that actually supplied the values.

style(compiler): prettier-format emitter-options test

4a1f1a1

Copilot AI lite review requested due to automatic review settings October 4, 2026 12:12

Tanvir Alam (tanvir-ux) force-pushed the fix/subpath-emitter-options branch from 2053239 to 4a1f1a1 Compare October 4, 2026 12:12

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@typespec/compiler - fix ✏️

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pkg-pr-new Bot commented Aug 27, 2026 •

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`@typespec/compiler` - fix ✏️