Tag-based targets in task deps not properly added to project dependencies

[arthur-leclerc]

Hey, I have some trouble with tag-based targets in task dependencies.

When using tag-based targets in a task deps of a project, the targeted project of the dependency is not being automatically added to the project where the task is defined, despite the task having the dependency in its deps.

Let me illustrate this with a concrete example.

With the following global task in .moon/tasks/tag-terraform.yml:

tasks:
  terraform/docs:
    toolchain: system
    command: terraform-docs
    args:
      - markdown
      - document
      - --config
      - $workspaceRoot/.github/configs/terraform-docs/docs.yaml
      - --header-from
      - docs/header.md
      - .
    inputs:
      - /.github/configs/terraform-docs/docs.yaml
      - docs/header.md
      - '**/*.tf'
    outputs:
      - docs/index.md
    options:
      outputStyle: buffer-only-failure

And x project, for example terraform/project-x/moon.yml using it:

id: terraform/project-x

tags:
  - terraform

When configuring a task dependency using a tag-based target on another project, let say apps/docs/moon.yml:

The project dependency is not automatically added when using a tag-based target, but are when using a direct project reference.

id: docs

tasks:
  build:
    description: |-
      Build the documentation.
    command: $projectRoot/.venv/bin/mkdocs
    args:
      - build
      - --config-file
      - mkdocs.yml
      - --strict
      - --site-dir
      - $projectRoot/site/
    deps:
      - '#terraform:terraform/docs'            # <- Why this doesn't add the targeted projects as a dependency?
      - 'terraform/project-3:terraform/docs'  # <- This work as expected

    env:
      SOURCE_DATE_EPOCH: '0'
    inputs:
      - /mkdocs.yml
      - '**/*'
    outputs:
      - site/
    options:
      runFromWorkspaceRoot: true

What I don't understand is that when I list the docs:build task, I can see all the dependencies, including those using tag:

$ ❯ moon task docs:build
About  ────

  Build the documentation.

  Target: docs:build
  Project: docs
  Task: build
  Toolchain: python
  Type: build

Process ────
  [...]
  Depends on:
    - terraform/project-1:terraform/docs
    - terraform/project-2:terraform/docs
    - terraform/project-3:terraform/docs
    - terraform/project-4:terraform/docs
    - terraform/project-5:terraform/docs

But at the project level, I only see the one with the directly referenced project.

❯ moon project docs
Metadata ────

  Documentation for the DevOps team

  Name: DevOps - Docs

About  ────

  Project: docs
  Alias: docs
  Source: apps/docs
  Depends on:
    - terraform/project-3 (implicit, build)   # <- Why I'm not seeing project added as a dependency here when using a tag-based target?

When calling the docs:build task, I'm seeing the right behavior, Moon build each Terraform project docs before building the documentation.

However, when trying to detect if the project have been touched, I'm not getting the right result:

moon query touched-files | moon query projects --affected --id docs --downstream direct

Will return nothing if I modify a file in any Terraform project as these projects are not added as dependencies to the docs project.

Similarly, when using moon project-graph docs, I don't see my Terraform projects as dependencies when using tag-based targets.

Do I really need to list all the projects here? What's the point of using tag-based targets then?

Thank you for your help!

[milesj]

I think this may just be an oversight, so have been digging into it, and this is basically the problem:

The implicit inheriting of a project dependency occurs when building the project here: https://github.com/moonrepo/moon/blob/master/crates/project-builder/src/project_builder.rs#L313

But at this point, the target is still #terraform:terraform/docs and hasn't been expanded to the 5 individual targets yet.

That expansion doesn't happen until way later on when we're creating graph relationships: https://github.com/moonrepo/moon/blob/master/crates/workspace/src/workspace_builder.rs#L502

I'll have to think about this a bit.

[arthur-leclerc]

Hello there,

I was wondering if this topic has evolved with the latest versions of Moon (v1.41.7). I noticed that now the project correctly displays dependencies when I inspect it with moon project <project_id>.

moon ci is also able to understand that if a dependency changes, the project must be rebuilt. However, unfortunately, the command moon query projects --affected is still unable to detect changes or tell me whether the project is affected.

Nothing urgent, I'm just replying here to keep a record of the progress.