refactor!(action): detect when in private branches

This removes the need to use the private-repo-workaround input.

action.yml

@@ -5,7 +5,7 @@ description: |
   report.
 
   You can post this report as a comment to the PR associated with the current
-  branch and/or export the report as a markdown artifact.
+  branch and/or export the report as a JSON artifact.
 
   Requires `nix`, `jq`, `curl`, `sed`, `gunzip`, `tar` and `coreutils` to be in
   the runner's path.
@@ -19,75 +19,95 @@ description: |
       comment-on-pr: 'true'
       generate-artifact: 'false'
       artifact-name: 'size-report.md'
-      base-branch: ${{ github.base_ref }} # set to e.g. main if not triggered by a pull_request
-      job-name: '' # set to the name of this job if you want to enable comparisons
+      # If you want to enable comparisons set this to true
+      do-comparison: 'false'
+      job-name: '' # required if do-comparison is true
+      # This is the branch that will be compared against
+      base-branch: ${{ github.base_ref }} # or default branch if missing
   ```
 inputs:
   comment-on-pr:
-    description: Comment the report on the PR associated with the current branch.
+    description: |
+      Comment the report on the PR associated with the current branch.
+
+      This is a no-op in case no PR is associated with the current branch.
     default: 'true'
+  # Generate workflow artifact
   generate-artifact:
-    description: Export the generated markdown document as an artifact.
+    description: Export the generated markdown document as a workflow artifact.
     default: 'false'
   artifact-name:
     description: The name of the generated artifact.
     default: report.json
-  base-branch:
+  # Comparison Report (comment only)
+  do-comparison:
     description: |
-      The name of the base branch, defaults to github.base_ref which is only
-      available in pull_request triggered workflows, for other workflows
-      specify it manually.
+      When commenting on the PR compare the results with those in the base branch.
 
-      It will try to download the generated artifact from this branch so make
-      sure `generate-artifacte: true` when the workflow is running on that
-      branch.
-    default: ${{ github.base_ref }}
+      This is a no-op when `comment-on-pr: false`.
+
+      It requires `job-name` to be set.
+    default: 'false'
   job-name:
     description: |
       The name of the job running this action. If not set, no comparisons can
       be made.
     default: ''
-  private-repo-workaround:
+  base-branch:
     description: |
-      Forgejo doesn't support downloading artifacts through the API [see
-      codeberg.org/forgejo/forgejo#6315](https://codeberg.org/forgejo/forgejo/issues/6315).
+      The name of the base branch, defaults to `github.base_ref` if present
+      (when triggered by a `pull_request`). Otherwise defaults to the repo's
+      default branch. Set in case you want to override this behaviour.
 
-      As a workaround, checkout the base branch and regenerate the report.
-
-      This is very innefficient T-T and slow.
-    default: 'false'
+      It will try to download the generated artifact from this branch so make
+      sure `generate-artifacte: true` when the workflow is running on that
+      branch.
+    default: ${{ github.base_ref }}
 outputs:
 runs:
   using: 'composite'
   steps:
     - name: Create report
+      if: inputs.comment-on-pr == 'true' || inputs.generate-artifact == 'true'
+      env:
+        COMMENT: ${{ inputs.comment-on-pr == }}
+        ARTIFACT_NAME: ${{ inputs.artifact-name }}
+        DO_COMPARISON: ${{ inputs.do-comparison }}
+        BASE_BRANCH: ${{ inputs.base-branch }}
+        JOB_NAME: ${{ inputs.job-name }}
       run: |
+        . "$GITHUB_ACTION_PATH/utils.sh"
+
+        # Input validation
+        if [ "$DO_COMPARISON" = 'true' ] && [ -z "$JOB_NAME" ]; then
+          error 'job-name should be set if you want to generate a comparison report'
+          exit 1
+        fi
+
+        # Create Size Report
         "$GITHUB_ACTION_PATH/create-report.sh" > report.json
+
+        # Nothing else to do
+        if [ "$COMMENT" != 'true' ]; then exit 0; fi
+
+        # Try to do a comparison report
+        if [ "$DO_COMPARISON" = 'true' ]; then
+          if "$GITHUB_ACTION_PATH/retrieve-old-report.sh" && [ -f old-report.json ]; then
+            log "Reporting on sizes and comparing to sizes in $HEAD_BRANCH"
+
+            "$GITHUB_ACTION_PATH/comment_on_pr.sh" report.json old-report.json
+            exit 0
+          else
+            error 'Failed to do comparison, fallback to posting the report without them'
+          fi
+        fi
+
+        # Just report values
+        log 'Reporting on sizes'
+        "$GITHUB_ACTION_PATH/comment_on_pr.sh" report.json
     - name: Upload Artifact
       uses: https://code.forgejo.org/forgejo/upload-artifact@v4
       if: inputs.generate-artifact == 'true'
       with:
         path: report.json
         name: ${{ inputs.artifact-name }}
-    - name: Comment Report
-      if: inputs.comment-on-pr == 'true'
-      env:
-        ARTIFACT_NAME: ${{ inputs.artifact-name }}
-        HEAD_BRANCH: ${{ inputs.base-branch }}
-        JOB_NAME: ${{ inputs.job-name }}
-        PRIVATE_REPO: ${{ inputs.private-repo-workaround }}
-      run: |
-        . "${GITHUB_ACTION_PATH}/utils.sh"
-
-        if "$GITHUB_ACTION_PATH/retrieve-old-report.sh" && [ -f old-report.json ]; then
-          log "Reporting on sizes and comparing to sizes in $HEAD_BRANCH"
-
-          group 'Old report data'
-          cat old-report.json
-          endgroup
-
-          "$GITHUB_ACTION_PATH/comment_on_pr.sh" report.json old-report.json
-        else
-          log 'Reporting on sizes'
-          "$GITHUB_ACTION_PATH/comment_on_pr.sh" report.json
-        fi