CORE-57 - Surface javac diagnostics for runtime compile failures #180
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,136 @@ | ||
| /* | ||
| * Copyright 2013-2025 chronicle.software; SPDX-License-Identifier: Apache-2.0 | ||
| */ | ||
| package net.openhft.compiler; | ||
|
|
||
| import org.junit.Test; | ||
|
|
||
| import javax.tools.JavaCompiler; | ||
| import javax.tools.StandardJavaFileManager; | ||
| import javax.tools.ToolProvider; | ||
| import java.io.PrintWriter; | ||
| import java.io.StringWriter; | ||
| import java.util.Map; | ||
|
|
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| import static org.junit.Assert.*; | ||
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| public class CachedCompilerModuleClassLoaderReproTest { | ||
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| @Test | ||
| public void moduleLikeLoaderCanLoadClassAfterSuccessfulDefineClass() throws Exception { | ||
| ModuleLikeClassLoader loader = new ModuleLikeClassLoader(); | ||
| CachedCompiler compiler = new CachedCompiler(null, null); | ||
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| Class<?> clazz = compiler.loadFromJava(loader, | ||
| "app.Generated", | ||
| "package app; public class Generated { public int value() { return 42; } }"); | ||
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| assertEquals("app.Generated", clazz.getName()); | ||
| assertSame(clazz, loader.loadClass("app.Generated")); | ||
| assertEquals(42, clazz.getDeclaredMethod("value").invoke(clazz.getDeclaredConstructor().newInstance())); | ||
| } | ||
|
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| @Test | ||
| public void compileFailureForLoaderOnlyDependencyReportsJavacDiagnostics() throws Exception { | ||
| ModuleLikeClassLoader loader = new ModuleLikeClassLoader(); | ||
| defineLoaderOnlyDependency(loader); | ||
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| assertSame("Sanity check: the supplied class loader can see the dependency", | ||
| loader.loadClass("app.Dto"), | ||
| Class.forName("app.Dto", false, loader)); | ||
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| CachedCompiler compiler = new CachedCompiler(null, null); | ||
| StringWriter diagnostics = new StringWriter(); | ||
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| ClassNotFoundException thrown = assertThrows(ClassNotFoundException.class, | ||
| () -> compiler.loadFromJava(loader, | ||
| "app.GeneratedUsesDto", | ||
| "package app; public class GeneratedUsesDto { app.Dto dto; }", | ||
| new PrintWriter(diagnostics))); | ||
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| assertTrue("Thrown exception should identify compilation failure: " + thrown.getMessage(), | ||
| thrown.getMessage().contains("Compilation failed for app.GeneratedUsesDto")); | ||
| assertTrue("Thrown exception should include javac missing-symbol diagnostics: " + thrown.getMessage(), | ||
| thrown.getMessage().contains("cannot find symbol")); | ||
| assertTrue("Thrown exception should include the dependency javac could not resolve: " + thrown.getMessage(), | ||
| thrown.getMessage().contains("Dto")); | ||
| assertNotNull("Thrown exception should carry a diagnostic cause", thrown.getCause()); | ||
| assertTrue("javac diagnostics should mention the dependency that the compiler could not resolve: " | ||
| + diagnostics, | ||
| diagnostics.toString().contains("Dto")); | ||
| assertNull("The generated class should not have been defined after javac failure", | ||
| loader.findLoaded("app.GeneratedUsesDto")); | ||
| } | ||
|
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| @Test | ||
| public void successfulCompileWithoutRequestedClassReportsMissingOutput() { | ||
| ModuleLikeClassLoader loader = new ModuleLikeClassLoader(); | ||
| CachedCompiler compiler = new CachedCompiler(null, null); | ||
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| ClassNotFoundException thrown = assertThrows(ClassNotFoundException.class, | ||
| () -> compiler.loadFromJava(loader, | ||
| "app.Expected", | ||
| "package app; class Different {}")); | ||
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| assertTrue("Thrown exception should identify the missing requested class: " + thrown.getMessage(), | ||
| thrown.getMessage().contains("Compilation did not produce requested class app.Expected")); | ||
| assertTrue("Thrown exception should identify the class javac actually produced: " + thrown.getMessage(), | ||
| thrown.getMessage().contains("app.Different")); | ||
| assertNotNull("Thrown exception should carry a diagnostic cause", thrown.getCause()); | ||
| assertNull("The requested class should not have been defined", | ||
| loader.findLoaded("app.Expected")); | ||
| } | ||
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| private static void defineLoaderOnlyDependency(ModuleLikeClassLoader loader) throws Exception { | ||
| JavaCompiler javac = ToolProvider.getSystemJavaCompiler(); | ||
| assertNotNull("System compiler required", javac); | ||
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| try (StandardJavaFileManager standardManager = javac.getStandardFileManager(null, null, null)) { | ||
| CachedCompiler bytecodeCompiler = new CachedCompiler(null, null); | ||
| MyJavaFileManager fileManager = new MyJavaFileManager(standardManager); | ||
| Map<String, byte[]> classes = bytecodeCompiler.compileFromJava( | ||
| "app.Dto", | ||
| "package app; public class Dto {}", | ||
| fileManager); | ||
| byte[] dtoBytes = classes.get("app.Dto"); | ||
| assertNotNull(dtoBytes); | ||
| CompilerUtils.defineClass(loader, "app.Dto", dtoBytes); | ||
| } | ||
| } | ||
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| private static final class ModuleLikeClassLoader extends ClassLoader { | ||
| private static final String APP_PREFIX = "app."; | ||
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| ModuleLikeClassLoader() { | ||
| super(CachedCompilerModuleClassLoaderReproTest.class.getClassLoader()); | ||
| } | ||
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| @Override | ||
| public Class<?> loadClass(String name) throws ClassNotFoundException { | ||
| return loadClass(name, false); | ||
| } | ||
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| @Override | ||
| protected Class<?> loadClass(String name, boolean resolve) throws ClassNotFoundException { | ||
| if (!name.startsWith(APP_PREFIX)) { | ||
| return super.loadClass(name, resolve); | ||
| } | ||
| return findClass(name, resolve); | ||
| } | ||
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| private Class<?> findClass(String name, boolean resolve) throws ClassNotFoundException { | ||
| Class<?> loaded = findLoadedClass(name); | ||
| if (loaded != null) { | ||
| if (resolve) { | ||
| resolveClass(loaded); | ||
| } | ||
| return loaded; | ||
| } | ||
| throw new ClassNotFoundException(name + " from [Module \"deployment.repro.war\" from Service Module Loader]"); | ||
| } | ||
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| Class<?> findLoaded(String name) { | ||
| return findLoadedClass(name); | ||
| } | ||
| } | ||
| } |
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This StringBuilder is captured in the DiagnosticListener lambda below, but if javac calls report() on multiple threads, then StringBuilder.append() will not be thread safe. Might be better to use StringBuffer or else explicit synchronisation, unless we can guarantee this will always be single-threaded ?
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The compile is done in this thread from the
call()method, so I don't think there foresee any concurrency issues