feat: Allow WORKSPACE Path Override (#12)

- Relaxes the assumption that the `path/to/WORKSPACE` is at the root of
the git repo.
- Add a required E2E test which checks out this repo and runs the
`compute_impacted_targets` test.

---------

Co-authored-by: Phil Vendola <[email protected]>

.github/workflows/e2e_tests.yaml

@@ -0,0 +1,40 @@
+name: Pull Request
+on: pull_request
+
+permissions: read-all
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    name: E2E Tests
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Setup Java
+        uses: actions/setup-java@v3
+        with:
+          distribution: oracle
+          java-version: "17"
+
+      - name: Setup Bazel
+        # trunk-ignore(semgrep): Trust third-party `bazelbuild` GH Action
+        uses: bazelbuild/setup-bazelisk@v2
+
+      - name: Compute Impacted Targets
+        id: compute
+        run: ./src/scripts/compute_impacted_targets.sh
+        shell: bash
+        env:
+          MERGE_INSTANCE_BRANCH: main
+          PR_BRANCH: do_not_delete/stable_test_branch
+          VERBOSE: 1
+          WORKSPACE_PATH: ./tests/simple_bazel_workspace
+
+      - name: Validate Impacted Targets Computation
+        shell: bash
+        run: |
+          target_count=`cat ${{ steps.compute.outputs.impacted_targets_out }} | wc -l`
+          if [[ $target_count -ne 2 ]]; then
+            exit 1
+          fi

action.yaml

@@ -11,6 +11,11 @@ inputs:
       The Merge Instance's target branch. If unspecified, defaults to the repository's default
       branch.
     required: false
+  bazel-workspace-path:
+    description:
+      The path to the bazel WORKSPACE, relative to the root of the git repository. If unspecified,
+      defaults to the root of the repository.
+    required: false
   verbose:
     description: Whether to enable verbose logging. Defaults to false.
     required: false
@@ -25,6 +30,7 @@ runs:
         java-version: "17"
 
     - name: Setup Bazel
+      # trunk-ignore(semgrep): Trust third-party `bazelbuild` GH Action
       uses: bazelbuild/setup-bazelisk@v2
 
     - name: Setup Tools
@@ -38,8 +44,9 @@ runs:
       run: ${GITHUB_ACTION_PATH}/src/scripts/prerequisites.sh
       shell: bash
       env:
-        TARGET_BRANCH: ${{ inputs.target-branch }}
         DEFAULT_BRANCH: ${{ github.event.repository.default_branch }}
+        TARGET_BRANCH: ${{ inputs.target-branch }}
+        WORKSPACE_PATH: ${{ inputs.bazel-workspace-path }}
 
     - name: Compute Impacted Targets
       id: compute-impacted-targets
@@ -49,6 +56,7 @@ runs:
         MERGE_INSTANCE_BRANCH: ${{ steps.prerequisites.outputs.merge_instance_branch }}
         PR_BRANCH: ${{ github.head_ref }}
         VERBOSE: ${{ inputs.verbose }}
+        WORKSPACE_PATH: ${{ steps.prerequisites.outputs.workspace_path }}
 
     - name: Upload Impacted Targets
       run: ${GITHUB_ACTION_PATH}/src/scripts/upload_impacted_targets.sh

src/scripts/compute_impacted_targets.sh

@@ -17,13 +17,17 @@ if [[ (-z ${MERGE_INSTANCE_BRANCH}) || (-z ${PR_BRANCH}) ]]; then
 	exit 2
 fi
 
+if [[ -z ${WORKSPACE_PATH} ]]; then
+	echo "Missing workspace path"
+	exit 2
+fi
+
 logIfVerbose "Fetching all remotes..."
 git fetch --all --quiet
 logIfVerbose "...done!"
 
 # Install the bazel-diff JAR. Avoid cloning the repo, as there will be conflicting WORKSPACES.
 curl -Lo bazel-diff.jar https://github.com/Tinder/bazel-diff/releases/latest/download/bazel-diff_deploy.jar
-workspace_path=$(pwd)
 
 git switch "${MERGE_INSTANCE_BRANCH}"
 git fetch --unshallow --quiet
@@ -59,11 +63,11 @@ impacted_targets_out=./impacted_targets_${pr_branch_head_sha}
 
 # Generate Hashes for the Merge Instance Branch
 git switch "${MERGE_INSTANCE_BRANCH}"
-java -jar bazel-diff.jar generate-hashes --workspacePath="${workspace_path}" "${merge_instance_branch_out}"
+java -jar bazel-diff.jar generate-hashes --workspacePath="${WORKSPACE_PATH}" "${merge_instance_branch_out}"
 
 # Generate Hashes for the Merge Instance Branch + PR Branch
 git -c "user.name=Trunk Actions" -c "[email protected]" merge --squash "${PR_BRANCH}"
-java -jar bazel-diff.jar generate-hashes --workspacePath="${workspace_path}" "${merge_instance_with_pr_branch_out}"
+java -jar bazel-diff.jar generate-hashes --workspacePath="${WORKSPACE_PATH}" "${merge_instance_with_pr_branch_out}"
 
 # Compute impacted targets
 java -jar bazel-diff.jar get-impacted-targets --startingHashes="${merge_instance_branch_out}" --finalHashes="${merge_instance_with_pr_branch_out}" --output="${impacted_targets_out}"

src/scripts/prerequisites.sh

@@ -12,5 +12,12 @@ if [[ -z ${merge_instance_branch} ]]; then
 	exit 2
 fi
 
+# trunk-ignore(shellcheck/SC2153): Passed in as env variable
+workspace_path="${WORKSPACE_PATH}"
+if [[ -z ${workspace_path} ]]; then
+	workspace_path=$(pwd)
+fi
+
 # Outputs
 echo "merge_instance_branch=${merge_instance_branch}" >>"${GITHUB_OUTPUT}"
+echo "workspace_path=${workspace_path}" >>"${GITHUB_OUTPUT}"