[GitHubActions] generator: typed workflow_dispatch inputs (string, boolean, number, choice, environment)

[avidenic]

Closes #386.

Adds a typed, compile-checked way to declare workflow_dispatch inputs via a new repeatable [GitHubActionsInput] attribute — replacing the untyped OnWorkflowDispatch*Inputs string arrays. Supports string/boolean/number/choice/environment, per-input default:, choice options:, and per-workflow scoping.

[GitHubActions("publish", GitHubActionsImage.UbuntuLatest, InvokedTargets = [nameof(Publish)])]
[GitHubActionsInput("DryRun", Type = GitHubActionsInputType.Boolean, Default = "false")]
[GitHubActionsInput("Channel", Type = GitHubActionsInputType.Choice, Options = ["alpha", "beta", "stable"], Default = "beta")]

on:
  workflow_dispatch:
    inputs:
      DryRun:
        description: "Dry Run"
        required: false
        type: boolean
        default: false
      Channel:
        description: "Channel"
        required: false
        type: choice
        default: beta
        options:
          - "alpha"
          - "beta"
          - "stable"

How it works

• Collected off the build class via Build.GetType().GetCustomAttributes<…>(), mirroring the existing [AppVeyorSecret]/[TeamCityToken] pattern. Scoped per workflow by Workflows (empty = every dispatch workflow).
• string inputs omit type:, so untyped output stays byte-identical. default: is emitted verbatim (per the issue; consistent with Env/CheckoutWith).
• GetImports() still feeds every input, so each stays importable as env: NAME: ${{ github.event.inputs.NAME }}.

Misconfiguration is loud

Generation throws ArgumentException (not silent) for: choice without options, default outside options, non-numeric/non-boolean default, options on a non-choice, an unknown Workflows target, and duplicate/blank input names.

Backward compatibility

• Legacy OnWorkflowDispatchOptionalInputs/RequiredInputs keep working, folded into the same model (emit first, untyped). Existing 9 snapshots are byte-identical.
• Both legacy arrays are now [Obsolete] → "Use [GitHubActionsInputAttribute] instead. Removed in 2027.x.x." Strictly additive; the removal is the future breaking change, batched to the year cut.

Tests

• GitHubActionsInputValidationTest.cs — every loud check.
• 3 Verify snapshot cases: dispatch-typed-inputs (all kinds), dispatch-input-scoping (Workflows filtering), dispatch-legacy-plus-typed (coexistence). The existing detailed-triggers case is now the regression guard for the obsolete legacy path.

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[ITaluone]

What are the opinions regarding [Obsolete] since this attribute can be a breaking change as well?

[avidenic]

What are the opinions regarding [Obsolete] since this attribute can be a breaking change as well?

Yeah, with TreatWarningsAsErrors it can. I Kept it warning-level as per AGENTS.md rule #2 a non-error [Obsolete] is the sanctioned deprecation; the removal (2027 major) is the actual break.

I can add a DiagnosticId so it's individually NoWarn-able if you'd prefer. I would probably need to add docs/obsolete-apis.md to mirror docs/experimental-apis.md. I think that route would warrant a separate issue / PR.

[ChrisonSimtian]

I'll try to look into this as soon as possible, promised. Just a bit busy at the moment :-(
To add to the discussion, I appreciate [Obsolete] and the DiagnosticId is a good idea!

[ChrisonSimtian]

@dennisdoomen this one please, I keep wanting to have a look but no spare time at the moment. This has been sitting here for a while now

[avidenic]

@ChrisonSimtian No rush, TYT =)

[avidenic]

@ChrisonSimtian I added #472 as a suggestion how to handle this.