feat: Upload google/guava and apache/pekko SCIP index (#329)

* Add index-guava job to SCIP examples workflow

- Uses scip-java container to index Google Guava repository
- Similar to index-k8s job but for Java instead of Go

Co-authored-by: Amp <amp@ampcode.com>
Amp-Thread-ID: https://ampcode.com/threads/T-9377a689-7d20-47bd-b80c-ad46731df1b0

* Simplify workflow using matrix strategy

- Consolidated two jobs into one with matrix strategy
- Removed redundant parameters (upload_repo, container, install_go)
- Derive values from scip_binary when possible
- Reduced workflow from 112 to ~75 lines

Co-authored-by: Amp <amp@ampcode.com>
Amp-Thread-ID: https://ampcode.com/threads/T-9377a689-7d20-47bd-b80c-ad46731df1b0

* Add Maven dependency caching for scip-java

Cache Maven artifacts to speed up scip-java runs that download many dependencies

Co-authored-by: Amp <amp@ampcode.com>
Amp-Thread-ID: https://ampcode.com/threads/T-9377a689-7d20-47bd-b80c-ad46731df1b0

* Refactor workflow: remove id param, fix Maven cache, handle tool-specific commands

- Dropped id parameter, use repository name directly
- Renamed checkout_repo to repository
- Fixed Maven cache key to avoid hashFiles error
- Added case statement to handle scip-go vs scip-java command differences

Co-authored-by: Amp <amp@ampcode.com>
Amp-Thread-ID: https://ampcode.com/threads/T-9377a689-7d20-47bd-b80c-ad46731df1b0

* Add more JVM repositories

Added `apache/pekko` and `arrow-kt/arrow`.

---------

Co-authored-by: Amp <amp@ampcode.com>

Author: jupblb

.github/workflows/scip-examples.yaml

@@ -9,39 +9,62 @@ permissions:
   contents: read
 
 jobs:
-  index-k8s:
+  index:
     if: github.repository == 'sourcegraph/scip' # Skip running on forks
     runs-on: ubuntu-latest
     timeout-minutes: 30
+
+    strategy:
+      fail-fast: false # If a job fails allow others to continue
+      matrix:
+        target:
+          - repository: kubernetes/kubernetes
+            scip_binary: scip-go
+          - repository: google/guava
+            scip_binary: scip-java
+          # scip-java has problems with indexing Kotlin codebase
+          # - repository: arrow-kt/arrow
+          #   scip_binary: scip-java
+          - repository: apache/pekko
+            scip_binary: scip-java
+
+    container: sourcegraph/${{ matrix.target.scip_binary }}:latest
     concurrency:
-      group: index-k8s
+      group: index-${{ matrix.target.repository }}
       cancel-in-progress: true
-    container: sourcegraph/scip-go:latest
     steps:
-      - name: Checkout kubernetes/kubernetes
+      - name: Checkout ${{ matrix.target.repository }}
         uses: actions/checkout@v5
         with:
-          repository: kubernetes/kubernetes
-          ref: master
+          repository: ${{ matrix.target.repository }}
           fetch-depth: 1
 
-      - name: Configure git safe.directory
-        run: git config --global --add safe.directory $GITHUB_WORKSPACE
-
-      - name: Get src-cli
-        run: |
-          curl -L https://sourcegraph.com/.api/src-cli/src_linux_amd64 \
-            -o /usr/local/bin/src
-          chmod +x /usr/local/bin/src
+      - name: Cache Maven dependencies
+        if: ${{ matrix.target.scip_binary == 'scip-java' }}
+        uses: actions/cache@v4
+        with:
+          path: ~/.m2/repository
+          key: ${{ runner.os }}-maven-${{ matrix.target.repository }}-${{ github.run_id }}
+          restore-keys: |
+            ${{ runner.os }}-maven-${{ matrix.target.repository }}-
+            ${{ runner.os }}-maven-
 
       - name: Install Go
+        if: ${{ matrix.target.scip_binary == 'scip-go' }}
         uses: actions/setup-go@v5
         with: { go-version-file: 'go.mod' }
 
-      - name: Run scip-go
+      - name: Run SCIP
         run: |
-          scip-go --version
-          scip-go --verbose
+          ${{ matrix.target.scip_binary }} --version
+          case "${{ matrix.target.scip_binary }}" in
+            scip-go)
+              ${{ matrix.target.scip_binary }} --verbose
+              ;;
+            scip-java)
+              ${{ matrix.target.scip_binary }} index --verbose
+              ;;
+          esac
 
       - name: Validate SCIP index size
         run: |
@@ -51,10 +74,19 @@ jobs:
           fi
           echo "SCIP dump size: $(du -h index.scip)"
 
+      - name: Configure git safe.directory
+        run: git config --global --add safe.directory $GITHUB_WORKSPACE
+
+      - name: Get src-cli
+        run: |
+          curl -L https://sourcegraph.com/.api/src-cli/src_linux_amd64 \
+            -o /usr/local/bin/src
+          chmod +x /usr/local/bin/src
+
       - name: Upload SCIP dump to Sourcegraph
         run: |
           src code-intel upload -no-progress \
-            -repo=github.com/kubernetes/kubernetes \
+            -repo=github.com/${{ matrix.target.repository }} \
             -file=index.scip
         env:
           SRC_ENDPOINT: https://sourcegraph.com/