`--build --dry` reports a noEmit project reference as perpetually out of date (expects emitted output that noEmit never produces)

Dieses Issue hat noch niemand übernommen.

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noEmit dry build`, `noEmit index.js does not exist dry build`, `build dry noEmit project references out-of-date`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

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

`lib/tsconfig.json`

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

`lib/index.ts`

```ts
export const value = 1
```

Run:

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The first dry run reports the referenced `noEmit` project as out of date because build info does not exist:

```text
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Project 'lib/tsconfig.json' is out of date because output file 'lib/tsconfig.tsbuildinfo' does not exist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:

```text
Project 'lib/tsconfig.json' is out of date because output file 'lib/tsconfig.tsbuildinfo' does not exist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:

```text
Project 'lib/tsconfig.json' is out of date because output file 'lib/index.js' does not exist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:

```text
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:

```text
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 |

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.

Vom Indexierungsmodell aus dem Issue-Text verfasst.