workflows: rename baseSha to targetSha

We currently use two different "base" commits, but the same name. One of
them is the commit in which context the pull_request_target runs. The
other is the parent of the merge commit. Those are **not** necessarily
the same - see README introduced in the next commit for details.

Renaming one of them for clarity. Since the pull_request_target related
base commit is also called like that in GitHub Actions terminology, we
rename the other. The best I could come up with is "target".

.github/workflows/check-nix-format.yml

@@ -31,13 +31,13 @@ jobs:
           # Fetches the merge commit and its parents
           fetch-depth: 2
 
-      - name: Checking out base branch
+      - name: Checking out target branch
         run: |
-          base=$(mktemp -d)
+          target=$(mktemp -d)
-          baseRev=$(git rev-parse HEAD^1)
+          targetRev=$(git rev-parse HEAD^1)
-          git worktree add "$base" "$baseRev"
+          git worktree add "$target" "$targetRev"
-          echo "baseRev=$baseRev" >> "$GITHUB_ENV"
+          echo "targetRev=$targetRev" >> "$GITHUB_ENV"
-          echo "base=$base" >> "$GITHUB_ENV"
+          echo "target=$target" >> "$GITHUB_ENV"
 
       - name: Get Nixpkgs revision for nixfmt
         run: |
@@ -85,12 +85,12 @@ jobs:
             esac
 
             # Ignore files that weren't already formatted
-            if [[ -n "$source" ]] && ! nixfmt --check ${{ env.base }}/"$source" 2>/dev/null; then
+            if [[ -n "$source" ]] && ! nixfmt --check ${{ env.target }}/"$source" 2>/dev/null; then
-              echo "Ignoring file $file because it's not formatted in the base commit"
+              echo "Ignoring file $file because it's not formatted in the target commit"
             elif ! nixfmt --check "$dest"; then
               unformattedFiles+=("$dest")
             fi
-          done < <(git diff -z --name-status ${{ env.baseRev }} -- '*.nix')
+          done < <(git diff -z --name-status ${{ env.targetRev }} -- '*.nix')
 
           if (( "${#unformattedFiles[@]}" > 0 )); then
             echo "Some new/changed Nix files are not properly formatted"

.github/workflows/check-nixf-tidy.yml

@@ -20,13 +20,13 @@ jobs:
           # Fetches the merge commit and its parents
           fetch-depth: 2
 
-      - name: Checking out base branch
+      - name: Checking out target branch
         run: |
-          base=$(mktemp -d)
+          target=$(mktemp -d)
-          baseRev=$(git rev-parse HEAD^1)
+          targetRev=$(git rev-parse HEAD^1)
-          git worktree add "$base" "$baseRev"
+          git worktree add "$target" "$targetRev"
-          echo "baseRev=$baseRev" >> "$GITHUB_ENV"
+          echo "targetRev=$targetRev" >> "$GITHUB_ENV"
-          echo "base=$base" >> "$GITHUB_ENV"
+          echo "target=$target" >> "$GITHUB_ENV"
 
       - name: Get Nixpkgs revision for nixf
         run: |
@@ -91,8 +91,8 @@ jobs:
                 continue
             esac
 
-            if [[ -n "$source" ]] && [[ "$(nixf_wrapper ${{ env.base }}/"$source")" != '[]' ]] 2>/dev/null; then
+            if [[ -n "$source" ]] && [[ "$(nixf_wrapper ${{ env.target }}/"$source")" != '[]' ]] 2>/dev/null; then
-              echo "Ignoring file $file because it doesn't pass nixf-tidy in the base commit"
+              echo "Ignoring file $file because it doesn't pass nixf-tidy in the target commit"
               echo # insert blank line
             else
               nixf_report="$(nixf_wrapper "$dest")"
@@ -119,7 +119,7 @@ jobs:
                 failedFiles+=("$dest")
               fi
             fi
-          done < <(git diff -z --name-status ${{ env.baseRev }} -- '*.nix')
+          done < <(git diff -z --name-status ${{ env.targetRev }} -- '*.nix')
 
           if [[ -n "$DONT_REPORT_ERROR" ]]; then
             echo "Edited the PR but didn't change the base branch, only the description/title."

.github/workflows/eval.yml

@@ -26,7 +26,7 @@ jobs:
     # Skip this and dependent steps if the PR can't be merged
     if: needs.get-merge-commit.outputs.mergedSha
     outputs:
-      baseSha: ${{ steps.baseSha.outputs.baseSha }}
+      targetSha: ${{ steps.targetSha.outputs.targetSha }}
       systems: ${{ steps.systems.outputs.systems }}
     steps:
       - name: Check out the PR at the test merge commit
@@ -36,12 +36,12 @@ jobs:
           fetch-depth: 2
           path: nixpkgs
 
-      - name: Determine base commit
+      - name: Determine target commit
         if: github.event_name == 'pull_request_target'
-        id: baseSha
+        id: targetSha
         run: |
-          baseSha=$(git -C nixpkgs rev-parse HEAD^1)
+          targetSha=$(git -C nixpkgs rev-parse HEAD^1)
-          echo "baseSha=$baseSha" >> "$GITHUB_OUTPUT"
+          echo "targetSha=$targetSha" >> "$GITHUB_OUTPUT"
 
       - name: Install Nix
         uses: cachix/install-nix-action@08dcb3a5e62fa31e2da3d490afc4176ef55ecd72 # v30
@@ -128,7 +128,7 @@ jobs:
     runs-on: ubuntu-24.04
     needs: [ outpaths, attrs, get-merge-commit ]
     outputs:
-      baseRunId: ${{ steps.baseRunId.outputs.baseRunId }}
+      targetRunId: ${{ steps.targetRunId.outputs.targetRunId }}
     steps:
       - name: Download output paths and eval stats for all systems
         uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4.1.8
@@ -158,11 +158,11 @@ jobs:
           name: result
           path: prResult/*
 
-      - name: Get base run id
+      - name: Get target run id
-        if: needs.attrs.outputs.baseSha
+        if: needs.attrs.outputs.targetSha
-        id: baseRunId
+        id: targetRunId
         run: |
-          # Get the latest eval.yml workflow run for the PR's base commit
+          # Get the latest eval.yml workflow run for the PR's target commit
           if ! run=$(gh api --method GET /repos/"$REPOSITORY"/actions/workflows/eval.yml/runs \
             -f head_sha="$BASE_SHA" -f event=push \
             --jq '.workflow_runs | sort_by(.run_started_at) | .[-1]') \
@@ -185,30 +185,30 @@ jobs:
             exit 0
           fi
 
-          echo "baseRunId=$runId" >> "$GITHUB_OUTPUT"
+          echo "targetRunId=$runId" >> "$GITHUB_OUTPUT"
         env:
           REPOSITORY: ${{ github.repository }}
-          BASE_SHA: ${{ needs.attrs.outputs.baseSha }}
+          BASE_SHA: ${{ needs.attrs.outputs.targetSha }}
           GH_TOKEN: ${{ github.token }}
 
       - uses: actions/download-artifact@v4
-        if: steps.baseRunId.outputs.baseRunId
+        if: steps.targetRunId.outputs.targetRunId
         with:
           name: result
-          path: baseResult
+          path: targetResult
           github-token: ${{ github.token }}
-          run-id: ${{ steps.baseRunId.outputs.baseRunId }}
+          run-id: ${{ steps.targetRunId.outputs.targetRunId }}
 
-      - name: Compare against the base branch
+      - name: Compare against the target branch
-        if: steps.baseRunId.outputs.baseRunId
+        if: steps.targetRunId.outputs.targetRunId
         run: |
-          git -C nixpkgs worktree add ../base ${{ needs.attrs.outputs.baseSha }}
+          git -C nixpkgs worktree add ../target ${{ needs.attrs.outputs.targetSha }}
-          git -C nixpkgs diff --name-only ${{ needs.attrs.outputs.baseSha }} \
+          git -C nixpkgs diff --name-only ${{ needs.attrs.outputs.targetSha }} \
             | jq --raw-input --slurp 'split("\n")[:-1]' > touched-files.json
 
-          # Use the base branch to get accurate maintainer info
+          # Use the target branch to get accurate maintainer info
-          nix-build base/ci -A eval.compare \
+          nix-build target/ci -A eval.compare \
-            --arg beforeResultDir ./baseResult \
+            --arg beforeResultDir ./targetResult \
             --arg afterResultDir ./prResult \
             --arg touchedFilesJson ./touched-files.json \
             -o comparison
@@ -216,7 +216,7 @@ jobs:
           cat comparison/step-summary.md >> "$GITHUB_STEP_SUMMARY"
 
       - name: Upload the combined results
-        if: steps.baseRunId.outputs.baseRunId
+        if: steps.targetRunId.outputs.targetRunId
         uses: actions/upload-artifact@6f51ac03b9356f520e9adb1b1b7802705f340c2b # v4.5.0
         with:
           name: comparison
@@ -227,7 +227,7 @@ jobs:
     name: Tag
     runs-on: ubuntu-24.04
     needs: [ attrs, process ]
-    if: needs.process.outputs.baseRunId
+    if: needs.process.outputs.targetRunId
     permissions:
       pull-requests: write
       statuses: write
@@ -254,7 +254,7 @@ jobs:
       - name: Check out Nixpkgs at the base commit
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
-          ref: ${{ needs.attrs.outputs.baseSha }}
+          ref: ${{ needs.attrs.outputs.targetSha }}
           path: base
           sparse-checkout: ci
 

.github/workflows/nixpkgs-vet.yml

@@ -39,11 +39,11 @@ jobs:
           # Fetches the merge commit and its parents
           fetch-depth: 2
 
-      - name: Checking out base branch
+      - name: Checking out target branch
         run: |
-          base=$(mktemp -d)
+          target=$(mktemp -d)
-          git worktree add "$base" "$(git rev-parse HEAD^1)"
+          git worktree add "$target" "$(git rev-parse HEAD^1)"
-          echo "base=$base" >> "$GITHUB_ENV"
+          echo "target=$target" >> "$GITHUB_ENV"
 
       - uses: cachix/install-nix-action@08dcb3a5e62fa31e2da3d490afc4176ef55ecd72 # v30
 
@@ -65,7 +65,7 @@ jobs:
           # Force terminal colors to be enabled. The library that `nixpkgs-vet` uses respects https://bixense.com/clicolors/
           CLICOLOR_FORCE: 1
         run: |
-          if result/bin/nixpkgs-vet --base "$base" .; then
+          if result/bin/nixpkgs-vet --base "$target" .; then
             exit 0
           else
             exitCode=$?