[bug] missing_dependency_hash in CI only

[kymckay]

Describe the bug

Upgrading to moon v2.0.4 we now see these failures in CI:

Error: task_runner::missing_dependency_hash
  
    × Encountered a missing hash for task events:build.schemas, which is a
    │ dependency of events:codegen.py.
    │ This either means the dependency hasn't ran, has failed, or there's a
    │ misconfiguration.
    │ 
    │ Try disabling the task's cache, or marking it as local.

Steps to reproduce

Here's our setup, those tasks:

  build.schemas:
    script: bash $projectRoot/scripts/build_schemas.sh
    inputs:
      - group: yaml-sources
      - file: scripts/build_schemas.sh
    outputs:
      - glob: "schemas/common/**/*.schema.json"
      - glob: "schemas/topics/**/*.schema.json"
    options:
      runFromWorkspaceRoot: true
  codegen.py:
    script: |
      mkdir -p $projectRoot/generated/python
      uv run datamodel-codegen \
        --input $projectRoot/schemas \
        --input-file-type jsonschema \
        --output $projectRoot/generated/python \
        --output-model-type pydantic_v2.BaseModel \
        --reuse-model \
        --use-standard-collections \
        --use-one-literal-as-default \
        --target-python-version 3.12 \
        --field-constraints \
        --no-treat-dot-as-module \
        --formatters ruff-format
    inputs:
      - glob: "schemas/**/*.schema.json"
    outputs:
      - glob: "generated/python/**/*"
    deps: [build.schemas]
    options:
      runFromWorkspaceRoot: true

We also run CI sharded, which is where this fails. It does not fail if I run the codegen.py task locally.

strategy:
  matrix:
    index: [0, 1, 2]
steps:
  - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
    with:
      fetch-depth: 0
      filter: tree:0
  - uses: ./.github/actions/setup-monorepo
  - name: Run CI
    env:
      BASE_SHA: ${{ github.event.pull_request.base.sha || '' }}
      HEAD_SHA: ${{ github.event.pull_request.head.sha || '' }}
      DEPOT_TOKEN: ${{ secrets.DEPOT_TOKEN }}
    run: |
      set -euo pipefail
      moon ci \
        --base "${BASE_SHA}" \
        --head "${HEAD_SHA}" \
        --downstream none \
        --upstream none \
        --job ${{ matrix.index }} --job-total 3

Expected behavior

CI should be running the task dependency and not reporting an issue.

Screenshots

Environment

Our CI runs on Depot's Ubuntu images.

Additional context

The same setup works fine in version 1 of moon, Claude suggested this may be related to the cache: false setting on dependency tasks, but that isn't the case for this example so I suspect it's a bug of some sort.

[milesj]

@kymckay In each shard, can you see which actions are running? Is it running codegen.py without running build.schemas?

[kymckay]

@milesj In the same shard I do see this in the logs:

▮▮▮▮ events:build.schemas (1s 94ms, 26b41afc)

[kymckay]

Perhaps the sharding is a red herring in that case. Another thing I ruled out is that I've disabled remote caching on this branch because I thought it could be something related to that, but the problem persists 🤔

[milesj]

If you can send over logs from each shard, that'll be useful.

[kymckay]

moon-ci.log.zip

Here I've enabled trace logging and reduced to a single shard to remove sharding from the equation. You'll notice this is happening for other tasks than the one in my original post, I've seen it happen for a variety - unclear whether it's a consistent subset of all our tasks, or it happens inconsistently on any task.

[milesj]

@kymckay Oh, I missed this initially, but you have --upstream none, which means "don't run any dependencies". Probably just remove that.

[kymckay]

Aha, that is it exactly. The behaviour of that must have changed in v2 as it was previously running dependencies still. This is net positive though, I think it's clearer this way as I didn't really understand why I had to set it to none to get the behaviour I wanted before.