microsoft / microsoft/TypeScript

`--build --dry` reports a noEmit project reference as perpetually out of date (expects emitted output that noEmit never produces)

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Description

Search Terms

noEmit --build --dry, tsconfig.tsbuildinfo noEmit dry build, noEmit index.js does not exist dry build, build dry noEmit project references out-of-date

Version & Regression Information

  • This is the behavior in every version I tried, and I reviewed the FAQ for entries about --build, noEmit, and project references.
  • Reproduced with typescript@5.9.3.
  • Reproduced with typescript@next version 7.1.0-dev.20260717.1.
  • Also reproduced with the TypeScript-Go port, tsgo version 7.0.0-dev+effect-tsgo.0.14.5.

Playground Link

No Playground link. This requires a multi-tsconfig.json project-reference graph and tsc --build --dry.

Code

tsconfig.json

{
  "files": [],
  "references": [
    {
      "path": "./lib"
    }
  ]
}

lib/tsconfig.json

{
  "compilerOptions": {
    "noEmit": true
  },
  "files": ["index.ts"]
}

lib/index.ts

export const value = 1

Run:

tsc --version
tsc --build tsconfig.json --dry --noCheck --verbose
tsc --build tsconfig.json --verbose
tsc --build tsconfig.json --dry --noCheck --verbose
tsc --build tsconfig.json --verbose
tsc --build tsconfig.json --dry --noCheck --verbose
tsc --build tsconfig.json --dry --verbose

Actual behavior

The first dry run reports the referenced noEmit project as out of date because build info does not exist:

Version 5.9.3

Projects in this build:
    * lib/tsconfig.json
    * tsconfig.json

Project 'lib/tsconfig.json' is out of date because output file 'lib/tsconfig.tsbuildinfo' does not exist
A non-dry build would build project '/tmp/ts-noemit-dry-repro/lib/tsconfig.json'

A non-dry build creates lib/tsconfig.tsbuildinfo but, correctly, does not create lib/index.js because noEmit is enabled:

Project 'lib/tsconfig.json' is out of date because output file 'lib/tsconfig.tsbuildinfo' does not exist
Building project '/tmp/ts-noemit-dry-repro/lib/tsconfig.json'...

After that, repeated dry and non-dry builds keep reporting the project as stale because lib/index.js does not exist:

Project 'lib/tsconfig.json' is out of date because output file 'lib/index.js' does not exist
A non-dry build would build project '/tmp/ts-noemit-dry-repro/lib/tsconfig.json'

This remains true after a second non-dry build:

Project 'lib/tsconfig.json' is out of date because output file 'lib/index.js' does not exist
Building project '/tmp/ts-noemit-dry-repro/lib/tsconfig.json'...

Project 'lib/tsconfig.json' is out of date because output file 'lib/index.js' does not exist
A non-dry build would build project '/tmp/ts-noemit-dry-repro/lib/tsconfig.json'

It is not specific to --noCheck; tsc --build tsconfig.json --dry --verbose reports the same missing lib/index.js output after the project has been built.

Expected behavior

Question: is this intended for noEmit projects in a --build references graph?

If this project shape is supported, I would expect build up-to-date logic not to require emitted JavaScript outputs for a project whose compilerOptions.noEmit guarantees those outputs will never exist. After a non-dry build creates the relevant build info, --build --dry should not report the project as perpetually needing a build because lib/index.js is missing.

If this project shape is not supported, it would be useful for --build to report that directly rather than producing a perpetual stale-output result.

Additional information about the issue

The same repro also appears in the TypeScript-Go port:

Version 7.0.0-dev+effect-tsgo.0.14.5

Project 'lib/tsconfig.json' is out of date because output file 'lib/tsconfig.tsbuildinfo' does not exist
A non-dry build would build project '/tmp/tsgo-noemit-dry-repro/lib/tsconfig.json'

Building project 'lib/tsconfig.json'...

Project 'lib/tsconfig.json' is out of date because output file 'lib/index.js' does not exist
A non-dry build would build project '/tmp/tsgo-noemit-dry-repro/lib/tsconfig.json'
Posted on behalf of @schickling
field value
agent_name 💎 co1-zenith
agent_session_id 0dee9117-f0f2-441f-a561-bbb08f2c7e5d
agent_tool Codex CLI
agent_tool_version 0.144.1
agent_runtime Codex CLI 0.144.1
agent_model unknown
runtime_profile /nix/store/1n76sy6i9y3ki3k4w04jksqvygw67sj0-coding-agent-runtime-profile/share/coding-agents/profile.json
skills_manifest /nix/store/jn6r0r7r59x3a525jch4pwzwykszqp60-agent-skills-corpus/share/agent-skills/manifest.json
worktree effect-utils/schickling/2026-07-17-tsgo-refactor
machine dev3
tooling_profile dotfiles@4eac376

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the issue with tsconfig.json, lib/tsconfig.json, and lib/index.ts using the listed tsc --build --dry --verbose commands. Trace the project-reference up-to-date checks for noEmit projects and add focused coverage if the relevant test location is found. Done means supported noEmit references no longer appear perpetually stale, or the command reports that this project shape is unsupported.

Written by the indexing model from the issue text.

Assessment

Tech stack
go, typescript
Domain
build-system, compilers
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
52/100

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