workflows: Consistently condition on merge commit

Before the get-merge-commit was put into a separate workflow job, it ran
as a step, which then required skipping all subsequent steps
individually. This is not necessary anymore, because entire workflow
jobs can be skipped.

This commit consistently applies that change throughout all workflows.

.github/workflows/eval-lib-tests.yml

@@ -15,9 +15,9 @@ jobs:
     name: nixpkgs-lib-tests
     runs-on: ubuntu-latest
     needs: get-merge-commit
+    if: needs.get-merge-commit.outputs.mergedSha
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        if: needs.get-merge-commit.outputs.mergedSha
         with:
           # pull_request_target checks out the base branch by default
           ref: ${{ needs.get-merge-commit.outputs.mergedSha }}

.github/workflows/eval.yml

@@ -23,54 +23,50 @@ jobs:
     name: Attributes
     runs-on: ubuntu-latest
     needs: get-merge-commit
+    # Skip this and dependent steps if the PR can't be merged
+    if: needs.get-merge-commit.outputs.mergedSha
     outputs:
-      mergedSha: ${{ needs.get-merge-commit.outputs.mergedSha }}
       baseSha: ${{ steps.baseSha.outputs.baseSha }}
       systems: ${{ steps.systems.outputs.systems }}
     steps:
       - name: Check out the PR at the test merge commit
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        # Add this to _all_ subsequent steps to skip them
-        if: needs.get-merge-commit.outputs.mergedSha
         with:
           ref: ${{ needs.get-merge-commit.outputs.mergedSha }}
           fetch-depth: 2
           path: nixpkgs
 
       - name: Determine base commit
-        if: github.event_name == 'pull_request_target' && needs.get-merge-commit.outputs.mergedSha
+        if: github.event_name == 'pull_request_target'
         id: baseSha
         run: |
           baseSha=$(git -C nixpkgs rev-parse HEAD^1)
           echo "baseSha=$baseSha" >> "$GITHUB_OUTPUT"
 
       - name: Install Nix
         uses: cachix/install-nix-action@08dcb3a5e62fa31e2da3d490afc4176ef55ecd72 # v30
-        if: needs.get-merge-commit.outputs.mergedSha
 
       - name: Evaluate the list of all attributes and get the systems matrix
         id: systems
-        if: needs.get-merge-commit.outputs.mergedSha
         run: |
           nix-build nixpkgs/ci -A eval.attrpathsSuperset
           echo "systems=$(<result/systems.json)" >> "$GITHUB_OUTPUT"
 
       - name: Upload the list of all attributes
         uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4.4.3
-        if: needs.get-merge-commit.outputs.mergedSha
         with:
           name: paths
           path: result/*
 
   eval-aliases:
     name: Eval nixpkgs with aliases enabled
     runs-on: ubuntu-latest
-    needs: attrs
+    needs: [ attrs, get-merge-commit ]
     steps:
       - name: Check out the PR at the test merge commit
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
-          ref: ${{ needs.attrs.outputs.mergedSha }}
+          ref: ${{ needs.get-merge-commit.outputs.mergedSha }}
           path: nixpkgs
 
       - name: Install Nix
@@ -83,9 +79,7 @@ jobs:
   outpaths:
     name: Outpaths
     runs-on: ubuntu-latest
-    needs: attrs
-    # Skip this and future steps if the PR can't be merged
-    if: needs.attrs.outputs.mergedSha
+    needs: [ attrs, get-merge-commit ]
     strategy:
       matrix:
         system: ${{ fromJSON(needs.attrs.outputs.systems) }}
@@ -99,7 +93,7 @@ jobs:
       - name: Check out the PR at the test merge commit
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
-          ref: ${{ needs.attrs.outputs.mergedSha }}
+          ref: ${{ needs.get-merge-commit.outputs.mergedSha }}
           path: nixpkgs
 
       - name: Install Nix
@@ -117,15 +111,14 @@ jobs:
 
       - name: Upload the output paths and eval stats
         uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4.4.3
-        if: needs.attrs.outputs.mergedSha
         with:
           name: intermediate-${{ matrix.system }}
           path: result/*
 
   process:
     name: Process
     runs-on: ubuntu-latest
-    needs: [ outpaths, attrs ]
+    needs: [ outpaths, attrs, get-merge-commit ]
     outputs:
       baseRunId: ${{ steps.baseRunId.outputs.baseRunId }}
     steps:
@@ -138,7 +131,7 @@ jobs:
       - name: Check out the PR at the test merge commit
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
-          ref: ${{ needs.attrs.outputs.mergedSha }}
+          ref: ${{ needs.get-merge-commit.outputs.mergedSha }}
           path: nixpkgs
 
       - name: Install Nix

.github/workflows/nixpkgs-vet.yml

@@ -29,24 +29,21 @@ jobs:
     # This should take 1 minute at most, but let's be generous. The default of 6 hours is definitely too long.
     timeout-minutes: 10
     needs: get-merge-commit
+    if: needs.get-merge-commit.outputs.mergedSha
     steps:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        if: needs.get-merge-commit.outputs.mergedSha
         with:
           # pull_request_target checks out the base branch by default
           ref: ${{ needs.get-merge-commit.outputs.mergedSha }}
           # Fetches the merge commit and its parents
           fetch-depth: 2
       - name: Checking out base branch
-        if: needs.get-merge-commit.outputs.mergedSha
         run: |
           base=$(mktemp -d)
           git worktree add "$base" "$(git rev-parse HEAD^1)"
           echo "base=$base" >> "$GITHUB_ENV"
       - uses: cachix/install-nix-action@08dcb3a5e62fa31e2da3d490afc4176ef55ecd72 # v30
-        if: needs.get-merge-commit.outputs.mergedSha
       - name: Fetching the pinned tool
-        if: needs.get-merge-commit.outputs.mergedSha
         # Update the pinned version using ci/nixpkgs-vet/update-pinned-tool.sh
         run: |
           # The pinned version of the tooling to use.
@@ -59,7 +56,6 @@ jobs:
           # Adds a result symlink as a GC root.
           nix-store --realise "$toolPath" --add-root result
       - name: Running nixpkgs-vet
-        if: needs.get-merge-commit.outputs.mergedSha
         env:
           # Force terminal colors to be enabled. The library that `nixpkgs-vet` uses respects https://bixense.com/clicolors/
           CLICOLOR_FORCE: 1