Restore optimization

changelog/@unreleased/pr-898.v2.yml

@@ -0,0 +1,6 @@
+type: fix
+fix:
+  description: Restore perf optimization to reuse the same classloader for conjure
+    generators when using gradle 7.4.2
+  links:
+  - https://github.com/palantir/gradle-conjure/pull/898

gradle-conjure/src/main/java/com/palantir/gradle/conjure/GradleExecUtils.java

@@ -16,21 +16,48 @@
 
 package com.palantir.gradle.conjure;
 
+import com.palantir.gradle.conjure.ConjureRunnerResource.Params;
 import java.io.File;
 import java.io.IOException;
 import java.util.List;
+import org.gradle.api.Action;
 import org.gradle.api.Project;
+import org.gradle.api.services.BuildServiceSpec;
+import org.gradle.util.GradleVersion;
 
 final class GradleExecUtils {
 
     static void exec(
             Project project, String failedTo, File executable, List<String> unloggedArgs, List<String> loggedArgs) {
-        try (ConjureRunnerResource.ConjureRunner runner = ConjureRunnerResource.createNewRunner(executable)) {
-            runner.invoke(project, failedTo, unloggedArgs, loggedArgs);
-        } catch (IOException e) {
-            throw new RuntimeException(e);
+        if (gradleVersionHighEnough()) {
+            project.getGradle()
+                    .getSharedServices()
+                    .registerIfAbsent(
+                            // Executable name must be the cache key, neither the spec parameters
+                            // nor the class are taken into account for caching.
+                            "conjure-runner-" + executable,
+                            ConjureRunnerResource.class,
+                            new Action<BuildServiceSpec<Params>>() {
+                                @Override
+                                public void execute(BuildServiceSpec<Params> spec) {
+                                    spec.getParameters().getExecutable().set(executable);
+                                }
+                            })
+                    .get()
+                    .invoke(project, failedTo, unloggedArgs, loggedArgs);
+        } else {
+            try (ConjureRunnerResource.ConjureRunner runner = ConjureRunnerResource.createNewRunner(executable)) {
+                runner.invoke(project, failedTo, unloggedArgs, loggedArgs);
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
         }
     }
 
+    // See https://github.com/gradle/gradle/issues/17434
+    private static boolean gradleVersionHighEnough() {
+        return GradleVersion.current().compareTo(GradleVersion.version("7.4.2")) >= 0;
+    }
+
     private GradleExecUtils() {}
 }