feat(output): add number and context outputs, soft-deprecate issue_number #100

Summary

Extend outputs so consumers can:

1. Read the issue/PR number from a new generic field named number (rather than issue_number).
2. Detect the triggering context (issue vs pull_request) from a new context output that mirrors the allowed_contexts input vocabulary.

issue_number remains functional in v1 and is marked as deprecated in the description only (soft deprecation). It will be removed in the next major release.

Motivation

• issue_number is misleading on pull-request contexts: GitHub assigns the same number space to issues and pull requests, but the field name implies "issue only". Users invoking the command from a PR comment currently have to recall that issue_number also carries the PR number — which is non-obvious.
• The action already accepts an allowed_contexts input with values issue / pull_request, but there is no output that tells downstream steps which of the two actually triggered the run. Today this requires recomputing context.payload.issue.pull_request != null in user-side script. Exposing it as context removes that duplication.
• Renaming via a parallel field keeps v1 fully backward compatible.

Proposed changes

1. Add number output

• Add a new output number that emits the value currently emitted by issue_number.
• Source: context.payload.issue.number.
• Semantics: the issue number for an issue context, and the PR number for a pull_request context (i.e., identical to GitHub's own numbering).

2. Soft-deprecate issue_number

• Keep emitting issue_number with the same value as today.
• Update its description in action.yaml to be prefixed with [Deprecated] and to recommend number.
• No runtime warning is emitted. (Documentation-only deprecation.)
• Removal is scheduled for the next major release; tracked separately (see Out of scope).

3. Add context output

• Add a new output context whose value is "issue" or "pull_request".
• Determination rule: "pull_request" if context.payload.issue.pull_request != null, else "issue". The existing isPr calculation in isValidContext (src/main.ts:26) is the source of truth — extract it so both call sites use the same logic.

Output emission timing

All three new/changed outputs follow the existing pattern: emitted alongside comment_id / actor / issue_number after isValidContext returns true. This matches the current behavior (these outputs exist when the action proceeds, regardless of whether continue ends up "true" or "false").

Spec details

action.yaml

outputs:
  continue: { description: "..." }
  params: { description: "..." }
  comment_id: { description: "..." }
  actor: { description: "..." }
  issue_number:
    description: '[Deprecated] The issue number of the comment that triggered this action. Use `number` instead. This output will be removed in the next major release.'
  number:
    description: 'The number of the issue or pull request that triggered this action.'
  context:
    description: 'The context that triggered this action. One of `"issue"` or `"pull_request"`.'
  command: { description: "..." }

src/main.ts

• After isValidContext passes, additionally set:
  • core.setOutput('number', context.payload.issue!.number!);
  • core.setOutput('context', isPr ? 'pull_request' : 'issue');
• isPr should be lifted out of isValidContext (or both call sites should call a shared helper) to keep a single source of truth.

README

• Update the Outputs table to include number and context.
• Mark issue_number as deprecated and link to number.

Acceptance criteria

• action.yaml declares number and context outputs with descriptions above.
• action.yaml description of issue_number is prefixed with [Deprecated] and recommends number.
• src/main.ts emits number, context, and continues to emit issue_number with the same value as today.
• number === issue_number for both issue and pull_request contexts.
• context === "pull_request" when the comment is on a PR, otherwise "issue".
• When isValidContext returns false, none of number / context / issue_number are emitted (matches current issue_number behavior).
• pnpm build produces an updated dist/, committed in the same PR.
• pnpm generate is run (inputs unchanged, but README Outputs table is regenerated).
• Unit/integration tests cover: (a) issue context, (b) pull_request context, (c) invalid context (no new outputs emitted).
• README Outputs table reflects the new fields and the deprecation note.
• No drift: CI checks for dist/ and generated docs pass.

Out of scope

• Removal of issue_number (tracked for the next major release; create a follow-up issue or milestone).
• Emitting a runtime deprecation warning via core.warning. May be added later if user feedback shows the doc-only deprecation is insufficient.
• Exposing additional issue/PR metadata (title, author, labels, etc.). Defer to a separate request.
• Renaming/expanding allowed_contexts to match a future event-type taxonomy.

Migration

For consumers of v1:

- run: echo "${{ steps.command.outputs.issue_number }}"
+ run: echo "${{ steps.command.outputs.number }}"

issue_number continues to work in v1; switch at your own pace.

Assumptions

• The Outputs table in README.md is regenerated by pnpm generate; if not, it must be edited by hand. Confirm during implementation.
• Naming the new output context is acceptable even though context is also the conventional name of the @actions/github context object in user workflows. Disambiguation lives at the access path (steps.<id>.outputs.context), so no real collision.
• "Next major release" is the right horizon for removing issue_number. No specific timeline is committed.

References

• action.yaml:25-28 — current issue_number and command outputs.
• src/main.ts:26 — current isPr computation.
• src/main.ts:58-60 — current output emission site for issue_number / comment_id / actor.
• README §Outputs.