ci(e2e): split e2e back into per-OS pipelines for true parallelism

Folding OS into the e2e matrix forced every cell to wait for the entire

build matrix to finish (Linux + Windows), so a slow Windows build delayed

Linux e2e jobs by ~2.5 min unnecessarily (Copilot review feedback).

Split back into independent per-OS pipelines:

  build-linux   -> e2e-linux  (matrix on plan)

  build-windows -> e2e-windows (matrix on plan)

Both pipelines feed into the shared discover-plans + analyze jobs, so the

unified entry point and combined summary are preserved.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: wenytang-ms

.github/workflows/e2eUI.yml

@@ -6,18 +6,24 @@ on:
   pull_request:
     branches: [ main ]
 
-# Unified parallel E2E UI pipeline for Linux + Windows.
+# Split-pipeline E2E UI workflow.
 #
 #   lint              → tslint + checkstyle (ubuntu, OS-agnostic)
 #   discover-plans    → emits a matrix of test-plan basenames
-#   build  (matrix)   → produces one VSIX per OS, uploaded as artifact
-#   e2e    (matrix)   → cartesian product of {os × plan}, all running in parallel
-#   analyze           → aggregates results from BOTH OSes into one unified summary
 #
-# Modelled after vscode-java-pack/.github/workflows/e2e-autotest.yml; matrix
-# has been extended with an `os` dimension so a single `e2e` job covers both
-# platforms. Each matrix cell surfaces as its own PR check, so failures are
-# visible without an extra gate job.
+#   build-linux       ─┐
+#   e2e-linux  (×plan) ┤
+#                      ├──→ analyze  → unified summary covering both OSes
+#   build-windows     ─┤
+#   e2e-windows (×plan)┘
+#
+# Per-OS pipelines run completely independently: Linux e2e jobs do NOT
+# wait for the Windows VSIX build (and vice versa), so a slow Windows
+# build cannot delay the start of Linux e2e plans. Each matrix cell
+# surfaces as its own PR check, so failures are visible without an
+# extra gate job.
+#
+# Inspired by vscode-java-pack/.github/workflows/e2e-autotest.yml.
 
 jobs:
   # ── Lint + Checkstyle (OS-agnostic) ─────────────────────
@@ -66,15 +72,11 @@ jobs:
           echo "matrix=$plans" >> "$GITHUB_OUTPUT"
           echo "Found plans: $plans"
 
-  # ── Build VSIX (one per OS) ─────────────────────────────
-  build:
-    name: Build VSIX (${{ matrix.os }})
-    runs-on: ${{ matrix.os }}
+  # ── Build VSIX (Linux) ──────────────────────────────────
+  build-linux:
+    name: Build VSIX (Linux)
+    runs-on: ubuntu-latest
     timeout-minutes: 20
-    strategy:
-      fail-fast: false
-      matrix:
-        os: [ ubuntu-latest, windows-latest ]
     steps:
       - uses: actions/checkout@v4
 
@@ -104,27 +106,63 @@ jobs:
       - name: Upload VSIX artifact
         uses: actions/upload-artifact@v4
         with:
-          name: vsix-${{ matrix.os }}
+          name: vsix-linux
           path: vscode-java-dependency.vsix
           retention-days: 1
 
-  # ── Run every (OS × plan) combo in parallel ─────────────
-  e2e:
-    name: E2E (${{ matrix.os }} / ${{ matrix.plan }})
-    needs: [ build, discover-plans ]
-    runs-on: ${{ matrix.os }}
+  # ── Build VSIX (Windows) ────────────────────────────────
+  build-windows:
+    name: Build VSIX (Windows)
+    runs-on: windows-latest
+    timeout-minutes: 20
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+
+      - name: Setup Node.js environment
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Install Node.js modules
+        run: npm install
+
+      - name: Install VSCE
+        run: npm install -g @vscode/vsce
+
+      - name: Build OSGi bundle
+        run: npm run build-server
+
+      - name: Build VSIX file
+        run: vsce package -o vscode-java-dependency.vsix
+
+      - name: Upload VSIX artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: vsix-windows
+          path: vscode-java-dependency.vsix
+          retention-days: 1
+
+  # ── E2E plans (Linux) — depends only on Linux build ─────
+  e2e-linux:
+    name: E2E Linux (${{ matrix.plan }})
+    needs: [ build-linux, discover-plans ]
+    runs-on: ubuntu-latest
     timeout-minutes: 25
     strategy:
       fail-fast: false
       matrix:
-        os: [ ubuntu-latest, windows-latest ]
         plan: ${{ fromJson(needs.discover-plans.outputs.matrix) }}
 
     steps:
       - uses: actions/checkout@v4
 
-      - name: Setup Linux Build Environment (Xvfb)
-        if: runner.os == 'Linux'
+      - name: Setup Build Environment (Xvfb)
         run: |
           sudo apt-get update
           sudo apt-get install -y libxkbfile-dev pkg-config libsecret-1-dev libxss1 dbus xvfb libgtk-3-0 libgbm1
@@ -151,11 +189,10 @@ jobs:
       - name: Download VSIX artifact
         uses: actions/download-artifact@v4
         with:
-          name: vsix-${{ matrix.os }}
+          name: vsix-linux
           path: .
 
-      - name: E2E Test — ${{ matrix.plan }} (Linux)
-        if: runner.os == 'Linux'
+      - name: E2E Test — ${{ matrix.plan }}
         shell: bash
         env:
           AZURE_OPENAI_ENDPOINT: ${{ secrets.AZURE_OPENAI_ENDPOINT }}
@@ -166,8 +203,49 @@ jobs:
             --vsix "$(pwd)/vscode-java-dependency.vsix" \
             --output "test-results/${{ matrix.plan }}"
 
-      - name: E2E Test — ${{ matrix.plan }} (Windows)
-        if: runner.os == 'Windows'
+      - name: Upload test results
+        if: ${{ always() }}
+        uses: actions/upload-artifact@v4
+        with:
+          name: e2e-results-linux-${{ matrix.plan }}
+          path: test-results/
+          retention-days: 7
+
+  # ── E2E plans (Windows) — depends only on Windows build ─
+  e2e-windows:
+    name: E2E Windows (${{ matrix.plan }})
+    needs: [ build-windows, discover-plans ]
+    runs-on: windows-latest
+    timeout-minutes: 25
+    strategy:
+      fail-fast: false
+      matrix:
+        plan: ${{ fromJson(needs.discover-plans.outputs.matrix) }}
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Set up JDK 21
+        uses: actions/setup-java@v4
+        with:
+          java-version: '21'
+          distribution: 'temurin'
+
+      - name: Setup Node.js environment
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Setup autotest
+        run: npm install -g @vscjava/vscode-autotest
+
+      - name: Download VSIX artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: vsix-windows
+          path: .
+
+      - name: E2E Test — ${{ matrix.plan }}
         shell: pwsh
         env:
           AZURE_OPENAI_ENDPOINT: ${{ secrets.AZURE_OPENAI_ENDPOINT }}
@@ -180,14 +258,14 @@ jobs:
         if: ${{ always() }}
         uses: actions/upload-artifact@v4
         with:
-          name: e2e-results-${{ matrix.os }}-${{ matrix.plan }}
+          name: e2e-results-windows-${{ matrix.plan }}
           path: test-results/
           retention-days: 7
 
   # ── Unified analysis across both OSes ───────────────────
   analyze:
     name: E2E Summary
-    needs: e2e
+    needs: [ e2e-linux, e2e-windows ]
     if: ${{ always() }}
     runs-on: ubuntu-latest
     steps:
@@ -210,17 +288,15 @@ jobs:
         shell: bash
         run: |
           mkdir -p test-results
-          # Artifact dir names look like: e2e-results-ubuntu-latest-<plan>
-          # or                            e2e-results-windows-latest-<plan>
-          for dir in all-results/e2e-results-ubuntu-latest-*/; do
+          for dir in all-results/e2e-results-linux-*/; do
             [ -d "$dir" ] || continue
             find "$dir" -name "results.json" -exec dirname {} \; | while read d; do
               name=$(basename "$d")
               mkdir -p "test-results/linux-$name"
               cp -r "$d"/. "test-results/linux-$name"/
             done
           done
-          for dir in all-results/e2e-results-windows-latest-*/; do
+          for dir in all-results/e2e-results-windows-*/; do
             [ -d "$dir" ] || continue
             find "$dir" -name "results.json" -exec dirname {} \; | while read d; do
               name=$(basename "$d")