Normalize extendedJavaHome environment variable for AdoptOpenJDK

Author: joschi

src/installer.ts

@@ -447,7 +447,13 @@ async function downloadJavaBinary(
     toolPath = await tc.cacheDir(jdkDir, toolName, versionSpec, arch);
   }
 
-  const extendedJavaHome = `JAVA_HOME_${version}_${arch}`;
+  let extendedJavaHome = `JAVA_HOME_${version}_${arch}`;
+  core.exportVariable(extendedJavaHome, toolPath); //TODO: remove for v2
+  // For portability reasons environment variables should only consist of
+  // uppercase letters, digits, and the underscore. Therefore we convert
+  // the extendedJavaHome variable to upper case and replace '.' symbols and
+  // any other non-alphanumeric characters with an underscore.
+  extendedJavaHome = extendedJavaHome.toUpperCase().replace(/[^0-9A-Z_]/g, '_');
   core.exportVariable('JAVA_HOME', toolPath);
   core.exportVariable(extendedJavaHome, toolPath);
   core.addPath(path.join(toolPath, 'bin'));