From 813809ebeb035488f48930d0f078257d6c6a28ea Mon Sep 17 00:00:00 2001
From: daz <daz@gradle.com>
Date: Wed, 3 Jan 2024 20:51:14 -0700
Subject: [PATCH] Merge into existing toolchains.xml

---
 .../integ-test-detect-java-toolchains.yml        | 10 +++++++++-
 src/cache-base.ts                                | 16 ++++++++++++++--
 2 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/.github/workflows/integ-test-detect-java-toolchains.yml b/.github/workflows/integ-test-detect-java-toolchains.yml
index 2aad0071..7fd32e6c 100644
--- a/.github/workflows/integ-test-detect-java-toolchains.yml
+++ b/.github/workflows/integ-test-detect-java-toolchains.yml
@@ -79,9 +79,17 @@ jobs:
       run: | 
         gradle --info javaToolchains > output.txt
         cat output.txt
-    - name: Verify detected toolchains
+    - name: Verify setup JDKs are detected
       shell: bash
       working-directory: .github/workflow-samples/groovy-dsl
       run: | 
         grep -q 'Eclipse Temurin JDK 16' output.txt || (echo "::error::Did not detect setup-java installed JDK 16" && exit 1)
         grep -q 'Eclipse Temurin JDK 20' output.txt || (echo "::error::Did not detect setup-java installed JDK 20" && exit 1)
+    - name: Verify pre-installed toolchains are detected
+      shell: bash
+      working-directory: .github/workflow-samples/groovy-dsl
+      run: | 
+        grep -q 'Eclipse Temurin JDK 1.8' output.txt || (echo "::error::Did not detect preinstalled JDK 1.8" && exit 1)
+        grep -q 'Eclipse Temurin JDK 11' output.txt || (echo "::error::Did not detect preinstalled JDK 11" && exit 1)
+        grep -q 'Eclipse Temurin JDK 17' output.txt || (echo "::error::Did not detect preinstalled JDK 17" && exit 1)
+        grep -q 'Eclipse Temurin JDK 21' output.txt || (echo "::error::Did not detect preinstalled JDK 21" && exit 1)
diff --git a/src/cache-base.ts b/src/cache-base.ts
index ce035642..467dde5b 100644
--- a/src/cache-base.ts
+++ b/src/cache-base.ts
@@ -204,15 +204,27 @@ export class GradleStateCache {
             fs.writeFileSync(initScriptPath, initScriptContent)
         }
 
-        // Copy the toolchain definitions file to `~/.m2/toolchains.xml` (if the file doesn't already exist)
+        // Copy the default toolchain definitions to `~/.m2/toolchains.xml`
+        const toolchainContent = this.readResourceFileAsString('toolchains.xml')
         const m2dir = path.resolve(this.userHome, '.m2')
         const toolchainXmlTarget = path.resolve(m2dir, 'toolchains.xml')
         if (!fs.existsSync(toolchainXmlTarget)) {
+            // Write a new toolchains.xml file if it doesn't exist
             fs.mkdirSync(m2dir, {recursive: true})
-            const toolchainContent = this.readResourceFileAsString('toolchains.xml')
             fs.writeFileSync(toolchainXmlTarget, toolchainContent)
 
             core.info(`Wrote default JDK locations to ${toolchainXmlTarget}`)
+        } else {
+            // Merge into an existing toolchains.xml file
+            const existingToolchainContent = fs.readFileSync(toolchainXmlTarget, 'utf8')
+            const appendedContent = toolchainContent.split("<toolchains>").pop()!
+            const mergedContent = existingToolchainContent.replace('</toolchains>', appendedContent)
+
+            core.info(`Merged toolchains.xml`)
+            core.info(mergedContent)
+
+            fs.writeFileSync(toolchainXmlTarget, mergedContent)
+            core.info(`Merged default JDK locations into ${toolchainXmlTarget}`)
         }
     }