findConfigDirs selects enclosing config by filename order instead of distance

[grouville]

Context

#1 implemented dagger/dagger#13688 and documents that findConfigDirs returns the nearest enclosing project. While reviewing dagger/typescript-sdk#11, a nested mixed-filename layout exposed that parentConfigDir instead accepts the first successful findUp in filename order.

Reproduction

Signed-off failing integration test: grouville@cbefe1a

git clone https://github.com/dagger/polyfill.git
cd polyfill
git fetch https://github.com/grouville/polyfill.git repro/nearest-mixed-config
git cherry-pick cbefe1ac5f72d91c763774b85f7d25c9a4c5a93c
dagger --x-release=v1.0.0-beta.7 check e-2-e:find-config-dirs-nearest-mixed-filename-check --progress=plain

The test constructs:

parent/
├── deno.json
└── child/
    ├── deno.jsonc
    └── nested/  # cwd

with filenames ordered as ["deno.json", "deno.jsonc"].

Expected: [".."], resolving to the nearer parent/child project.

Actual: ["../.."], resolving to parent, because the farther deno.json is checked first.

The lookup should compare all successful findUp results and select the closest ancestor regardless of filename order.

[grouville]

Additional downstream evidence

The same filename-order bug appears in two independent consumers of findConfigDirs while implementing dagger/dagger#13688:

Consumer	Filename order	Farther ancestor	Nearer project
dagger/ruff#1	pyproject.toml, ruff.toml, .ruff.toml	pyproject.toml	ruff.toml
dagger/pytest#19	pytest.ini, pyproject.toml, tox.ini, setup.cfg	pytest.ini	pyproject.toml

Both repositories contain the same logical fixture:

ancestor/
├── first-filename-config
└── work/
    └── app/
        ├── nearer-second-filename-config
        └── deep/
            └── nested/                 # caller cwd

From deep/nested, the nearest enclosing project is app, so findConfigDirs should return:

../..

It currently returns:

../../../..

That path resolves to ancestor. The first filename's successful findUp is retained before the nearer second filename is considered.

There is a second symptom when the caller is exactly at app: walk-down adds . for the local config, while find-up independently adds the farther ancestor selected through the first filename. The result contains both . and an ancestor even though the local config should shadow it.

Reproduce with Ruff

gh repo clone grouville/ruff
cd ruff
git switch feat/cwd-aware-discovery
mkdir -p tests/discovery/ancestor/work/app/deep/nested
cd tests/discovery/ancestor/work/app/deep/nested
dagger call ruff projects

Expected: ../.., resolving to work/app/ruff.toml.

Actual: ../../../.., resolving to ancestor/pyproject.toml.

Reproduce with Pytest

gh repo clone grouville/pytest
cd pytest
git switch feat/cwd-aware-discovery
mkdir -p tests/discovery/ancestor/work/app/deep/nested
cd tests/discovery/ancestor/work/app/deep/nested
dagger call pytest projects

Expected: ../.., resolving to work/app/pyproject.toml.

Actual: ../../../.., resolving to ancestor/pytest.ini.

Downstream impact

The Ruff and Pytest adapters otherwise work as intended at the workspace root and from a configless parent: their fixture-based checks prove that automatic operations include descendants and exclude strict ancestors.

The deeper case cannot be made reliable in each adapter without reimplementing nearest-config selection. Fixing the distance comparison in polyfill and repinning consumers preserves the purpose of the shared API.

dagger/python-sdk#9 is also a consumer. Its explicit mod lookup already compares config distances, but its bulk modules path intentionally delegates to findConfigDirs and can inherit the reverse mixed-filename case.