gnodet commented on code in PR #1157: URL: https://github.com/apache/maven-compiler-plugin/pull/1157#discussion_r4192585760
########## src/main/java/org/apache/maven/plugin/compiler/incremental/GraphIncrementalBuild.java: ########## @@ -0,0 +1,910 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ +package org.apache.maven.plugin.compiler.incremental; + +import java.io.IOException; +import java.io.UncheckedIOException; +import java.nio.file.Files; +import java.nio.file.Path; +import java.nio.file.attribute.BasicFileAttributes; +import java.util.ArrayDeque; +import java.util.ArrayList; +import java.util.LinkedHashMap; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.TreeSet; +import java.util.stream.Collectors; + +/** + * Dependency-graph-driven incremental build engine, designed for embedding + * in maven-compiler-plugin alongside the existing timestamp-based + * {@code IncrementalBuild}. + * + * <p>The plugin drives compilation; this class determines <em>what</em> to + * compile and performs post-compilation bytecode analysis to build the + * class-level dependency graph. Typical usage: + * + * {@snippet : + * var build = new GraphIncrementalBuild(outputDir); + * build.setProcessorPath(processorPath); + * build.setConfigHash(configHash); + * + * Set<Path> toCompile = build.initialize(allSourceFiles); + * + * while (!toCompile.isEmpty()) { + * compiler.compile(toCompile); // any compiler, any mode + * toCompile = build.processCompiledClasses(toCompile); + * } + * + * build.finish(); + * } + * + * <p>After each compilation pass, {@link #processCompiledClasses(Set)} scans + * the freshly produced {@code .class} files, updates the dependency graph, + * and returns any additional source files that must be compiled in the next + * pass (cascade due to changed classes, or newly discovered dependencies). + * The loop converges in at most 2–3 passes in practice. + * + * <p>The engine persists its state as {@code incremental-state} in the + * {@code target/maven-status/maven-compiler-plugin/<outputDirName>/} directory (outside the class + * output directory so it is not packaged into JARs). + * + * @see IncrementalState + */ +public class GraphIncrementalBuild { + + /** Prefix used to distinguish module-info entries from regular type entries in the state. */ + static final String MODULE_PREFIX = BytecodeAnalyzer.MODULE_PREFIX; + + private final Path outputDir; + private final Path buildDir; + private final Path stateFile; + private List<Path> classpathEntries; + private Set<Path> reactorModulePaths; + private List<Path> processorPath; + private ProcessorClassification processorClassification; + + private IncrementalState previousState; + private IncrementalState state; + + /** Package-private accessor for tests. */ + IncrementalState getState() { + return state; + } + + private Map<String, String> sourceHashes; + private Map<String, Long> sourceMtimes; + private List<Path> allSourceFiles; + private Set<String> allCompiled; + private boolean fullBuild; + private boolean useModulePrefixedPaths; + private String configHash = ""; + private String rebuildCause; + private int totalSources; + /** Lazily populated on full builds; maps each output class file to its simple top-level class name. */ + private Map<Path, String> outputClassIndex; + + public GraphIncrementalBuild(Path outputDir) { + this.outputDir = outputDir.toAbsolutePath(); + this.buildDir = this.outputDir.getParent() != null ? this.outputDir.getParent() : this.outputDir; + // Store state outside the output directory so it is not included in the JAR. + // Use the same maven-status convention as the timestamp-based strategy. + // Include the output directory name (e.g. "classes", "test-classes") to avoid + // collisions between compile and testCompile executions. + String outputDirName = outputDir.getFileName().toString(); + Path mavenStatus = buildDir.resolve("maven-status").resolve("maven-compiler-plugin"); + this.stateFile = mavenStatus.resolve(outputDirName).resolve("incremental-state"); + } + + /** + * Sets classpath entries for external dependency tracking. + */ + public void setClasspathEntries(List<Path> entries) { + this.classpathEntries = entries; + } + + /** + * Marks specific classpath entries as reactor modules. + */ + public void setReactorModulePaths(Set<Path> paths) { + this.reactorModulePaths = paths; + } + + /** + * Sets the annotation processor classpath for processor classification. + * Entries are scanned for {@code META-INF/maven/compiler/incremental.annotation.processors} + * and {@code META-INF/gradle/incremental.annotation.processors} to determine + * whether each processor is {@link ProcessorType#ISOLATING}, + * {@link ProcessorType#AGGREGATING}, or {@link ProcessorType#UNKNOWN}. + */ + public void setProcessorPath(List<Path> processorPath) { + this.processorPath = processorPath; + this.processorClassification = new ProcessorClassification(processorPath); + } + + /** + * Indicates that class files are written under module-name subdirectories + * of the output directory (MODULE_SOURCE hierarchy). When set, stored module + * names are used as path prefixes when deleting class files. + */ + public void setUseModulePrefixedPaths(boolean useModulePrefixedPaths) { + this.useModulePrefixedPaths = useModulePrefixedPaths; + } + + /** + * Sets a hash of compilation context configuration (e.g. compiler options + * and module-info-patch files). If this hash differs from the previous + * build, a full rebuild is triggered. + */ + public void setConfigHash(String hash) { + this.configHash = hash != null ? hash : ""; + } + + /** + * Initializes the incremental build by scanning source files and comparing + * against the previous build's state. + * + * @param allSourceFiles all source files in this module + * @return the set of files that need compilation (may be all files for a + * full build, a subset for incremental, or empty if up-to-date) + */ + public Set<Path> initialize(List<Path> allSourceFiles) throws IOException { + Files.createDirectories(outputDir); + + this.allSourceFiles = allSourceFiles; + totalSources = allSourceFiles.size(); + allCompiled = new TreeSet<>(); + previousState = IncrementalState.load(stateFile); + sourceMtimes = new LinkedHashMap<>(); + sourceHashes = hashSourceFiles(allSourceFiles, previousState, sourceMtimes); + + if (previousState == null) { + rebuildCause = "no previous build state"; + return initFullBuild(allSourceFiles); + } else if (!configHash.equals(previousState.getConfigHash())) { + rebuildCause = "compilation configuration changed (module-info-patch.maven or compiler options)"; + return initFullBuild(allSourceFiles); + } else { + return initIncrementalBuild(allSourceFiles); + } + } + + /** + * Processes the {@code .class} files produced by the last compilation pass. + * Scans each class file to extract the dependency graph, records changes, + * and returns any additional source files that must be compiled in the next pass. + * + * <p>The cascade logic: any compiled class whose content changed (new or modified) + * triggers recompilation of all source files that depend on it (signature or + * implementation consumers). + * + * @param compiledSourceFiles the source files that were passed to the compiler in this round + * @return additional source files to compile (may be empty when fixpoint is reached) + * @throws IOException if reading {@code .class} files fails + */ + public Set<Path> processCompiledClasses(Set<Path> compiledSourceFiles) throws IOException { + // Reset the class index so it is rebuilt fresh for each compilation round + outputClassIndex = null; + + // Scan .class files for the types produced from the compiled source files + var results = new LinkedHashMap<String, SourceFileAnalysis>(); + for (Path sourceFile : compiledSourceFiles) { + collectClassAnalyses(sourceFile, results); + } + + // All compiled types cascade to their consumers (any change triggers recompilation) + var changedTypes = new TreeSet<>(results.keySet()); + + // Update incremental state with this round's results + for (var entry : sourceHashes.entrySet()) { + if (allCompiled.contains(entry.getKey())) { + state.setSourceHash(entry.getKey(), entry.getValue()); + } + } + for (var result : results.values()) { + String moduleName = useModulePrefixedPaths ? result.moduleName() : ""; + IncrementalState.TypeInfo typeInfo; + typeInfo = new IncrementalState.GraphTypeInfo( + result.sourceFile(), result.classDeps(), result.annotationTypes(), moduleName); + state.setType(result.qualifiedName(), typeInfo); + } + + if (fullBuild || changedTypes.isEmpty()) { + return Set.of(); + } + + // Detect module name changes — require a full rebuild + if (previousState != null && hasModuleNameChanged(state, previousState)) { + return forceFullRebuild(); + } + + // Cascade: find all consumers of changed types (both signature and implementation) + var cascade = new TreeSet<>(changedTypes); + for (String type : changedTypes) { + expandSignatureCascade(type, state, cascade); + } + + var additionalFiles = new TreeSet<Path>(); + for (String cascadedType : cascade) { + for (String consumer : state.getAllConsumers(cascadedType)) { + String sf = state.sourceFileFor(consumer); + if (sf != null && !allCompiled.contains(sf)) { + additionalFiles.add(Path.of(sf)); + allCompiled.add(sf); + } + } + } + + // Annotation processor cascade + additionalFiles.addAll(computeProcessorCascade()); + + return additionalFiles; + } + + /** + * Scans the output directory for {@code .class} files produced from the given source file, + * analyzes each one with {@link BytecodeAnalyzer}, and accumulates {@link SourceFileAnalysis} + * records into {@code results}. + * + * <p>The source→class mapping is reconstructed by looking up types previously recorded for + * this source file in the previous state, and by scanning the output directory for class + * files whose name prefix matches the source file's simple name. This covers both primary + * classes and inner/anonymous classes ({@code Foo$Bar.class}). + */ + private void collectClassAnalyses(Path sourceFile, Map<String, SourceFileAnalysis> results) throws IOException { + String sourceFilePath = sourceFile.toString(); + String simpleSourceName = sourceFile.getFileName().toString(); // e.g. "Model.java" + + // Map from class file path → pre-computed analysis (null if not yet analyzed). + // Reuses the analysis from the package-dir walk to avoid double BytecodeAnalyzer.analyze calls. + var classFileCache = new LinkedHashMap<Path, BytecodeAnalyzer.ClassAnalysis>(); + + // Types previously tracked for this source file — their .class files may have moved + if (previousState != null) { + for (String type : previousState.getTypesFromSource(sourceFilePath)) { + Path classFile = classFileFor(type, previousState.getType(type)); + if (Files.exists(classFile)) { + classFileCache.put(classFile, null); + } + // Also scan for inner classes (Foo$Bar.class etc.) + var innerFiles = new TreeSet<Path>(); + addInnerClassFiles(classFile, innerFiles); + for (Path inner : innerFiles) { + classFileCache.putIfAbsent(inner, null); + } + } + } + + // Walk output directory entries for this source's simple name + // (handles new types introduced in this compilation) + Path packageDir = inferPackageDir(sourceFile); + if (packageDir != null && Files.isDirectory(packageDir)) { + try (var stream = Files.list(packageDir)) { + stream.filter(p -> p.toString().endsWith(".class")).forEach(cf -> { + try { + // Match by SourceFile attribute — covers primary class, inner/anonymous + // classes (Foo$Bar.class), AND package-private secondary top-level classes + // (FooHelper in Foo.java), without cross-package simple-name collisions. + var a = BytecodeAnalyzer.analyze(cf); + if (simpleSourceName.equals(a.sourceFileName())) { + classFileCache.put(cf, a); // cache the analysis for reuse below + } + } catch (IOException e) { + // Log at debug level — a corrupted or inaccessible class file is silently + // skipped; the missing type entry will trigger a full rebuild next time. + System.getLogger(GraphIncrementalBuild.class.getName()) + .log(System.Logger.Level.DEBUG, "Failed to analyze class file: {0}", cf); Review Comment: _Claude Code on behalf of Guillaume Nodet_ Fixed: replaced System.getLogger with a silent skip, consistent with the rest of the method's best-effort error handling. ########## src/main/java/org/apache/maven/plugin/compiler/incremental/GraphIncrementalBuild.java: ########## @@ -0,0 +1,910 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ +package org.apache.maven.plugin.compiler.incremental; + +import java.io.IOException; +import java.io.UncheckedIOException; +import java.nio.file.Files; +import java.nio.file.Path; +import java.nio.file.attribute.BasicFileAttributes; +import java.util.ArrayDeque; +import java.util.ArrayList; +import java.util.LinkedHashMap; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.TreeSet; +import java.util.stream.Collectors; + +/** + * Dependency-graph-driven incremental build engine, designed for embedding + * in maven-compiler-plugin alongside the existing timestamp-based + * {@code IncrementalBuild}. + * + * <p>The plugin drives compilation; this class determines <em>what</em> to + * compile and performs post-compilation bytecode analysis to build the + * class-level dependency graph. Typical usage: + * + * {@snippet : + * var build = new GraphIncrementalBuild(outputDir); + * build.setProcessorPath(processorPath); + * build.setConfigHash(configHash); + * + * Set<Path> toCompile = build.initialize(allSourceFiles); + * + * while (!toCompile.isEmpty()) { + * compiler.compile(toCompile); // any compiler, any mode + * toCompile = build.processCompiledClasses(toCompile); + * } + * + * build.finish(); + * } + * + * <p>After each compilation pass, {@link #processCompiledClasses(Set)} scans + * the freshly produced {@code .class} files, updates the dependency graph, + * and returns any additional source files that must be compiled in the next + * pass (cascade due to changed classes, or newly discovered dependencies). + * The loop converges in at most 2–3 passes in practice. + * + * <p>The engine persists its state as {@code incremental-state} in the + * {@code target/maven-status/maven-compiler-plugin/<outputDirName>/} directory (outside the class + * output directory so it is not packaged into JARs). + * + * @see IncrementalState + */ +public class GraphIncrementalBuild { + + /** Prefix used to distinguish module-info entries from regular type entries in the state. */ + static final String MODULE_PREFIX = BytecodeAnalyzer.MODULE_PREFIX; + + private final Path outputDir; + private final Path buildDir; + private final Path stateFile; + private List<Path> classpathEntries; + private Set<Path> reactorModulePaths; + private List<Path> processorPath; + private ProcessorClassification processorClassification; + + private IncrementalState previousState; + private IncrementalState state; + + /** Package-private accessor for tests. */ + IncrementalState getState() { + return state; + } + + private Map<String, String> sourceHashes; + private Map<String, Long> sourceMtimes; + private List<Path> allSourceFiles; + private Set<String> allCompiled; + private boolean fullBuild; + private boolean useModulePrefixedPaths; + private String configHash = ""; + private String rebuildCause; + private int totalSources; + /** Lazily populated on full builds; maps each output class file to its simple top-level class name. */ + private Map<Path, String> outputClassIndex; + + public GraphIncrementalBuild(Path outputDir) { + this.outputDir = outputDir.toAbsolutePath(); + this.buildDir = this.outputDir.getParent() != null ? this.outputDir.getParent() : this.outputDir; + // Store state outside the output directory so it is not included in the JAR. + // Use the same maven-status convention as the timestamp-based strategy. + // Include the output directory name (e.g. "classes", "test-classes") to avoid + // collisions between compile and testCompile executions. + String outputDirName = outputDir.getFileName().toString(); + Path mavenStatus = buildDir.resolve("maven-status").resolve("maven-compiler-plugin"); + this.stateFile = mavenStatus.resolve(outputDirName).resolve("incremental-state"); + } + + /** + * Sets classpath entries for external dependency tracking. + */ + public void setClasspathEntries(List<Path> entries) { + this.classpathEntries = entries; + } + + /** + * Marks specific classpath entries as reactor modules. + */ + public void setReactorModulePaths(Set<Path> paths) { + this.reactorModulePaths = paths; + } + + /** + * Sets the annotation processor classpath for processor classification. + * Entries are scanned for {@code META-INF/maven/compiler/incremental.annotation.processors} + * and {@code META-INF/gradle/incremental.annotation.processors} to determine + * whether each processor is {@link ProcessorType#ISOLATING}, + * {@link ProcessorType#AGGREGATING}, or {@link ProcessorType#UNKNOWN}. + */ + public void setProcessorPath(List<Path> processorPath) { + this.processorPath = processorPath; + this.processorClassification = new ProcessorClassification(processorPath); + } + + /** + * Indicates that class files are written under module-name subdirectories + * of the output directory (MODULE_SOURCE hierarchy). When set, stored module + * names are used as path prefixes when deleting class files. + */ + public void setUseModulePrefixedPaths(boolean useModulePrefixedPaths) { + this.useModulePrefixedPaths = useModulePrefixedPaths; + } + + /** + * Sets a hash of compilation context configuration (e.g. compiler options + * and module-info-patch files). If this hash differs from the previous + * build, a full rebuild is triggered. + */ + public void setConfigHash(String hash) { + this.configHash = hash != null ? hash : ""; + } + + /** + * Initializes the incremental build by scanning source files and comparing + * against the previous build's state. + * + * @param allSourceFiles all source files in this module + * @return the set of files that need compilation (may be all files for a + * full build, a subset for incremental, or empty if up-to-date) + */ + public Set<Path> initialize(List<Path> allSourceFiles) throws IOException { + Files.createDirectories(outputDir); + + this.allSourceFiles = allSourceFiles; + totalSources = allSourceFiles.size(); + allCompiled = new TreeSet<>(); + previousState = IncrementalState.load(stateFile); + sourceMtimes = new LinkedHashMap<>(); + sourceHashes = hashSourceFiles(allSourceFiles, previousState, sourceMtimes); + + if (previousState == null) { + rebuildCause = "no previous build state"; + return initFullBuild(allSourceFiles); + } else if (!configHash.equals(previousState.getConfigHash())) { + rebuildCause = "compilation configuration changed (module-info-patch.maven or compiler options)"; + return initFullBuild(allSourceFiles); + } else { + return initIncrementalBuild(allSourceFiles); + } + } + + /** + * Processes the {@code .class} files produced by the last compilation pass. + * Scans each class file to extract the dependency graph, records changes, + * and returns any additional source files that must be compiled in the next pass. + * + * <p>The cascade logic: any compiled class whose content changed (new or modified) + * triggers recompilation of all source files that depend on it (signature or + * implementation consumers). + * + * @param compiledSourceFiles the source files that were passed to the compiler in this round + * @return additional source files to compile (may be empty when fixpoint is reached) + * @throws IOException if reading {@code .class} files fails + */ + public Set<Path> processCompiledClasses(Set<Path> compiledSourceFiles) throws IOException { + // Reset the class index so it is rebuilt fresh for each compilation round + outputClassIndex = null; + + // Scan .class files for the types produced from the compiled source files + var results = new LinkedHashMap<String, SourceFileAnalysis>(); + for (Path sourceFile : compiledSourceFiles) { + collectClassAnalyses(sourceFile, results); + } + + // All compiled types cascade to their consumers (any change triggers recompilation) + var changedTypes = new TreeSet<>(results.keySet()); + + // Update incremental state with this round's results + for (var entry : sourceHashes.entrySet()) { + if (allCompiled.contains(entry.getKey())) { + state.setSourceHash(entry.getKey(), entry.getValue()); + } + } + for (var result : results.values()) { + String moduleName = useModulePrefixedPaths ? result.moduleName() : ""; + IncrementalState.TypeInfo typeInfo; + typeInfo = new IncrementalState.GraphTypeInfo( + result.sourceFile(), result.classDeps(), result.annotationTypes(), moduleName); + state.setType(result.qualifiedName(), typeInfo); + } + + if (fullBuild || changedTypes.isEmpty()) { + return Set.of(); + } + + // Detect module name changes — require a full rebuild + if (previousState != null && hasModuleNameChanged(state, previousState)) { + return forceFullRebuild(); + } + + // Cascade: find all consumers of changed types (both signature and implementation) + var cascade = new TreeSet<>(changedTypes); + for (String type : changedTypes) { + expandSignatureCascade(type, state, cascade); + } + + var additionalFiles = new TreeSet<Path>(); + for (String cascadedType : cascade) { + for (String consumer : state.getAllConsumers(cascadedType)) { + String sf = state.sourceFileFor(consumer); + if (sf != null && !allCompiled.contains(sf)) { + additionalFiles.add(Path.of(sf)); + allCompiled.add(sf); + } + } + } + + // Annotation processor cascade + additionalFiles.addAll(computeProcessorCascade()); + + return additionalFiles; + } + + /** + * Scans the output directory for {@code .class} files produced from the given source file, + * analyzes each one with {@link BytecodeAnalyzer}, and accumulates {@link SourceFileAnalysis} + * records into {@code results}. + * + * <p>The source→class mapping is reconstructed by looking up types previously recorded for + * this source file in the previous state, and by scanning the output directory for class + * files whose name prefix matches the source file's simple name. This covers both primary + * classes and inner/anonymous classes ({@code Foo$Bar.class}). + */ + private void collectClassAnalyses(Path sourceFile, Map<String, SourceFileAnalysis> results) throws IOException { + String sourceFilePath = sourceFile.toString(); + String simpleSourceName = sourceFile.getFileName().toString(); // e.g. "Model.java" + + // Map from class file path → pre-computed analysis (null if not yet analyzed). + // Reuses the analysis from the package-dir walk to avoid double BytecodeAnalyzer.analyze calls. + var classFileCache = new LinkedHashMap<Path, BytecodeAnalyzer.ClassAnalysis>(); + + // Types previously tracked for this source file — their .class files may have moved + if (previousState != null) { + for (String type : previousState.getTypesFromSource(sourceFilePath)) { + Path classFile = classFileFor(type, previousState.getType(type)); + if (Files.exists(classFile)) { + classFileCache.put(classFile, null); + } + // Also scan for inner classes (Foo$Bar.class etc.) + var innerFiles = new TreeSet<Path>(); + addInnerClassFiles(classFile, innerFiles); + for (Path inner : innerFiles) { + classFileCache.putIfAbsent(inner, null); + } + } + } + + // Walk output directory entries for this source's simple name + // (handles new types introduced in this compilation) + Path packageDir = inferPackageDir(sourceFile); + if (packageDir != null && Files.isDirectory(packageDir)) { + try (var stream = Files.list(packageDir)) { + stream.filter(p -> p.toString().endsWith(".class")).forEach(cf -> { + try { + // Match by SourceFile attribute — covers primary class, inner/anonymous + // classes (Foo$Bar.class), AND package-private secondary top-level classes + // (FooHelper in Foo.java), without cross-package simple-name collisions. + var a = BytecodeAnalyzer.analyze(cf); + if (simpleSourceName.equals(a.sourceFileName())) { + classFileCache.put(cf, a); // cache the analysis for reuse below + } + } catch (IOException e) { + // Log at debug level — a corrupted or inaccessible class file is silently + // skipped; the missing type entry will trigger a full rebuild next time. + System.getLogger(GraphIncrementalBuild.class.getName()) + .log(System.Logger.Level.DEBUG, "Failed to analyze class file: {0}", cf); + } + }); + } + } else { + // No previous state for this source (full build or new file in incremental build): + // use the cached class index keyed by SourceFile attribute value (simple source name, + // e.g. "Foo.java"). This correctly associates package-private secondary types and + // avoids cross-package simple-name collisions. + for (var entry : getFullBuildClassIndex().entrySet()) { + if (simpleSourceName.equals(entry.getValue())) { + classFileCache.putIfAbsent(entry.getKey(), null); + } + } + } + + // Special case: module-info.class — check both flat and module-prefixed locations + if (sourceFile.getFileName().toString().equals("module-info.java")) { + // Flat layout: outputDir/module-info.class + Path flat = outputDir.resolve("module-info.class"); + if (Files.exists(flat)) { + classFileCache.putIfAbsent(flat, null); + } + // MODULE_SOURCE layout: outputDir/<moduleName>/module-info.class + if (useModulePrefixedPaths && previousState != null) { + // Find the module name from previous state + for (String type : previousState.getTypesFromSource(sourceFile.toString())) { + if (type.startsWith(MODULE_PREFIX)) { + String modName = type.substring(MODULE_PREFIX.length()); + Path modInfo = outputDir.resolve(modName).resolve("module-info.class"); + if (Files.exists(modInfo)) { + classFileCache.putIfAbsent(modInfo, null); + } + break; + } + } + } + } + + // Final pass: analyze each class file (reusing cached analysis where available) + for (var cacheEntry : classFileCache.entrySet()) { + Path classFile = cacheEntry.getKey(); + if (!Files.exists(classFile)) { + continue; + } + try { + // Graph analysis: class-level deps only (constant pool scan) + // We still need className, sourceFileName, moduleName, annotationTypes + // from a lightweight analysis — use analyzeGraph for deps but full analyze + // for metadata (still one parse of the classfile via the classfile API). + var analysis = + cacheEntry.getValue() != null ? cacheEntry.getValue() : BytecodeAnalyzer.analyze(classFile); + String sourceFilePath2 = analysis.isModuleInfo() + ? sourceFilePath + : resolveSourceFile(analysis.className(), sourceFilePath); + Set<String> classDeps = unionDeps(analysis.signatureTypes(), analysis.implementationTypes()); + var sfa = new SourceFileAnalysis( + analysis.className(), + sourceFilePath2, + classDeps, + analysis.annotationTypes(), + analysis.moduleName()); + results.put(analysis.className(), sfa); + } catch (IOException e) { + // Skip unreadable class files — they'll be caught at compile time + } + } + } + + /** Returns the union of two sets (both may be empty). */ + private static Set<String> unionDeps(Set<String> a, Set<String> b) { + if (a.isEmpty()) { + return b; + } + if (b.isEmpty()) { + return a; + } + var result = new java.util.HashSet<String>(a); + result.addAll(b); + return Set.copyOf(result); + } + + private Map<Path, String> getFullBuildClassIndex() throws IOException { + if (outputClassIndex == null) { + outputClassIndex = new LinkedHashMap<>(); + if (Files.isDirectory(outputDir)) { + try (var walk = Files.walk(outputDir)) { + for (Path cf : + (Iterable<Path>) walk.filter(p -> p.toString().endsWith(".class"))::iterator) { + try { + var analysis = BytecodeAnalyzer.analyze(cf); + // Use the SourceFile attribute value — correctly handles package-private + // secondary types in the same file (e.g. FooHelper in Foo.java → "Foo.java"). + String sfName = analysis.sourceFileName(); + if (!sfName.isEmpty()) { + outputClassIndex.put(cf, sfName); + } + } catch (IOException e) { + // best effort — skip unreadable class files + } + } + } + } + } + return outputClassIndex; + } + + /** Returns the expected .class file path for a type, accounting for module-prefixed output dirs. */ + private Path classFileFor(String qualifiedName, IncrementalState.TypeInfo info) { + String moduleName = info != null ? info.moduleName() : ""; + Path base = (useModulePrefixedPaths && !moduleName.isEmpty()) ? outputDir.resolve(moduleName) : outputDir; + if (qualifiedName.startsWith(MODULE_PREFIX)) { + return base.resolve("module-info.class"); + } + return base.resolve(qualifiedName.replace('.', '/') + ".class"); + } + + private static void addInnerClassFiles(Path primaryClassFile, Set<Path> result) { + if (!Files.exists(primaryClassFile)) { + return; + } + Path dir = primaryClassFile.getParent(); + if (dir == null || !Files.isDirectory(dir)) { + return; + } + String prefix = primaryClassFile.getFileName().toString().replace(".class", "$"); + try (var stream = Files.list(dir)) { + stream.filter(p -> p.getFileName().toString().startsWith(prefix) + && p.getFileName().toString().endsWith(".class")) + .forEach(result::add); + } catch (IOException e) { + // Best effort + } + } + + /** + * Infers the package directory in the output tree for the given source file, + * based on the types previously recorded for it in the incremental state. + * Accounts for module-prefixed output directories when {@code useModulePrefixedPaths} is true. + */ + private Path inferPackageDir(Path sourceFile) { + if (previousState == null) { + return null; + } + String sourceFilePath = sourceFile.toString(); + for (String type : previousState.getTypesFromSource(sourceFilePath)) { + if (!type.startsWith(MODULE_PREFIX)) { + String pkg = type.contains(".") + ? type.substring(0, type.lastIndexOf('.')).replace('.', '/') + : ""; + // Determine base dir: for module-prefixed output, classes live under outputDir/<module>/ + var info = previousState.getType(type); + String moduleName = (useModulePrefixedPaths && info != null) ? info.moduleName() : ""; + Path base = (!moduleName.isEmpty()) ? outputDir.resolve(moduleName) : outputDir; + return pkg.isEmpty() ? base : base.resolve(pkg); + } + } + return null; + } + + /** Returns the source file to associate with a class, preferring the known path if available. */ + private String resolveSourceFile(String className, String defaultSourceFile) { + if (state != null) { + String sf = state.sourceFileFor(className); + if (sf != null) { + return sf; + } + } + return defaultSourceFile; + } + + /** + * Finalizes the incremental build and persists the state. + */ + public void finish() throws IOException { + if (state == null) { + return; + } + + // Persist source mtimes for the next build's mtime-first optimization + for (var entry : sourceMtimes.entrySet()) { + state.setSourceMtime(entry.getKey(), entry.getValue()); + } + + state.setConfigHash(configHash); + state.save(stateFile); + } + + /** + * Invalidates the incremental state after a compilation failure. + * Deletes the state file so the next build starts fresh, avoiding + * a broken output directory where class files were deleted but + * not regenerated. + */ + public void invalidate() { + try { + Files.deleteIfExists(stateFile); + } catch (IOException e) { + // Best effort — a missing state file just triggers a full rebuild + } + } + + /** + * Returns whether this was a full build (no previous state). + */ + public boolean isFullBuild() { + return fullBuild; + } + + /** + * Returns the total number of files compiled across all rounds. + */ + public int compiledCount() { + return allCompiled.size(); + } + + /** + * Returns the total number of files that were unchanged. + */ + public int unchangedCount() { + return totalSources - allCompiled.size(); + } + + /** + * Returns a human-readable description of why recompilation was triggered, + * or {@code null} if no rebuild is needed. + */ + public String getRebuildCause() { + return rebuildCause; + } + + // --- Initialization --- + + private Set<Path> initFullBuild(List<Path> allSourceFiles) { + fullBuild = true; + state = new IncrementalState(); + state.setClasspathIdentities(computeCurrentJarIdentities()); + + var files = new TreeSet<Path>(); + for (Path f : allSourceFiles) { + files.add(f); + allCompiled.add(f.toString()); + } + return files; + } + + private Set<Path> initIncrementalBuild(List<Path> allSourceFiles) { + fullBuild = false; + state = previousState.copy(); + + // Detect source changes + var changedFiles = new TreeSet<String>(); + var newFiles = new TreeSet<String>(); + var deletedFiles = new TreeSet<>(previousState.getSourceHashes().keySet()); + + for (var entry : sourceHashes.entrySet()) { + String path = entry.getKey(); + String hash = entry.getValue(); + deletedFiles.remove(path); + + String previousHash = previousState.getSourceHash(path); + if (previousHash == null) { + newFiles.add(path); + } else if (!hash.equals(previousHash)) { + changedFiles.add(path); + } + } + + // Check external classpath changes + Set<String> externallyInvalidated = checkExternalClasspathChanges(); + + if (changedFiles.isEmpty() && newFiles.isEmpty() && deletedFiles.isEmpty() && externallyInvalidated.isEmpty()) { + return Set.of(); + } + + // Build rebuild cause description + var causes = new ArrayList<String>(); + if (!changedFiles.isEmpty()) { + causes.add(changedFiles.size() + " changed"); + } + if (!newFiles.isEmpty()) { + causes.add(newFiles.size() + " new"); + } + if (!deletedFiles.isEmpty()) { + causes.add(deletedFiles.size() + " deleted"); + } + if (!externallyInvalidated.isEmpty()) { + causes.add(externallyInvalidated.size() + " invalidated by dependency changes"); + } + rebuildCause = String.join(", ", causes); + + // Build initial recompilation set + var toRecompile = new TreeSet<String>(); + toRecompile.addAll(changedFiles); + toRecompile.addAll(newFiles); + toRecompile.addAll(externallyInvalidated); + + // Consumers of deleted types + for (String deleted : deletedFiles) { + for (String type : previousState.getTypesFromSource(deleted)) { + for (String consumer : previousState.getAllConsumers(type)) { + String sf = previousState.sourceFileFor(consumer); + if (sf != null) { + toRecompile.add(sf); + } + } + deleteClassFile(type, previousState.getType(type)); + } + state.removeSource(deleted); + } + + // Clear stale type entries and class files for files about to be recompiled — + // handles cases where a source file previously defined multiple types + // (including inner/nested classes) but now defines fewer + for (String sourceFile : toRecompile) { + for (String type : previousState.getTypesFromSource(sourceFile)) { + deleteClassFile(type, previousState.getType(type)); + } + state.removeTypesForSource(sourceFile); + } + + allCompiled.addAll(toRecompile); + var result = new TreeSet<Path>(); + for (String s : toRecompile) { + result.add(Path.of(s)); + } + return result; + } + + // --- Annotation processor handling --- + + /** + * Determines additional files to compile based on annotation processor classification. + * Called during incremental builds when annotated sources are in the compile set. + * + * <ul> + * <li>ISOLATING: no extra files needed (default, current behavior works)</li> + * <li>AGGREGATING: all sources carrying the processor's trigger annotations</li> + * <li>UNKNOWN: all sources (conservative full rebuild)</li> + * </ul> + */ + private Set<Path> computeProcessorCascade() { + if (processorClassification == null) { + return Set.of(); + } + + // Collect annotation types from types we just compiled + var compiledAnnotations = new TreeSet<String>(); + for (var entry : state.getTypes().entrySet()) { + if (allCompiled.contains(state.sourceFileFor(entry.getKey()))) { + compiledAnnotations.addAll(entry.getValue().annotationTypes()); + } + } + + if (compiledAnnotations.isEmpty()) { + return Set.of(); + } + + // Check if any compiled annotation triggers an AGGREGATING or UNKNOWN processor + boolean hasUnknown = false; + boolean hasAggregating = false; + + // Use worst-case classification from the processor path + var allAnnotations = state.getAllAnnotationTypes(); + if (allAnnotations.isEmpty()) { + return Set.of(); + } + + // Check if any processors on the path are UNKNOWN or AGGREGATING + var classificationMap = processorClassification.getClassifications(); + for (var entry : classificationMap.entrySet()) { + if (entry.getValue() == ProcessorType.UNKNOWN) { + hasUnknown = true; + } else if (entry.getValue() == ProcessorType.AGGREGATING) { + hasAggregating = true; + } + } + + // If no processors are classified at all but processor path is set, + // we can't know what annotations they handle — conservative approach + if (classificationMap.isEmpty() && processorPath != null && !processorPath.isEmpty()) { + hasUnknown = true; + } + + var additionalFiles = new TreeSet<Path>(); + + if (hasUnknown) { + // UNKNOWN: recompile all source files + for (Path sf : allSourceFiles) { + if (!allCompiled.contains(sf.toString())) { + additionalFiles.add(sf); + allCompiled.add(sf.toString()); + } + } + } else if (hasAggregating) { + // AGGREGATING: recompile all annotated sources + Set<String> annotatedFiles = state.getSourceFilesWithAnnotations(allAnnotations); + for (String sf : annotatedFiles) { + if (!allCompiled.contains(sf)) { + additionalFiles.add(Path.of(sf)); + allCompiled.add(sf); + } + } + } + // ISOLATING: no extra files needed + + return additionalFiles; + } + + // --- Utility --- + + private static boolean hasModuleNameChanged(IncrementalState current, IncrementalState previous) { + var currentModules = current.getTypes().keySet().stream() + .filter(k -> k.startsWith(MODULE_PREFIX)) + .collect(Collectors.toSet()); + var previousModules = previous.getTypes().keySet().stream() + .filter(k -> k.startsWith(MODULE_PREFIX)) + .collect(Collectors.toSet()); + return !currentModules.equals(previousModules); + } + + private Set<Path> forceFullRebuild() { + // Delete old class files for types not yet recompiled + for (var entry : previousState.getTypes().entrySet()) { + String sf = entry.getValue().sourceFile(); + if (sf != null && !allCompiled.contains(sf)) { + deleteClassFile(entry.getKey(), entry.getValue()); + } + } + var additionalFiles = new TreeSet<Path>(); + for (Path sf : allSourceFiles) { + if (!allCompiled.contains(sf.toString())) { + additionalFiles.add(sf); + allCompiled.add(sf.toString()); + } + } + return additionalFiles; + } + + private void expandSignatureCascade(String startType, IncrementalState state, Set<String> result) { + var worklist = new ArrayDeque<String>(); + worklist.add(startType); + while (!worklist.isEmpty()) { + String type = worklist.poll(); + for (String consumer : state.getSignatureConsumers(type)) { + if (result.add(consumer)) { + worklist.add(consumer); + } + } + } + } + + private void deleteClassFile(String qualifiedName, IncrementalState.TypeInfo info) { + String moduleName = info != null ? info.moduleName() : ""; + Path baseDir = moduleName.isEmpty() ? outputDir : outputDir.resolve(moduleName); + + if (qualifiedName.startsWith(MODULE_PREFIX)) { + Path moduleInfoClass = baseDir.resolve("module-info.class"); + try { + Files.deleteIfExists(moduleInfoClass); + } catch (IOException e) { + throw new UncheckedIOException("Failed to delete module-info.class", e); + } + return; + } + Path classFile = baseDir.resolve(qualifiedName.replace('.', '/') + ".class"); + try { + Files.deleteIfExists(classFile); + // Also clean up inner/nested class files (Foo$Bar.class, Foo$Bar$Baz.class, etc.) + // These are generated by javac alongside the top-level class file. + Path classDir = classFile.getParent(); + String simplePrefix = classFile.getFileName().toString().replace(".class", "$"); + if (Files.isDirectory(classDir)) { + try (var stream = Files.list(classDir)) { + stream.filter(p -> p.getFileName().toString().startsWith(simplePrefix) + && p.getFileName().toString().endsWith(".class")) + .forEach(p -> { + try { + Files.deleteIfExists(p); + } catch (IOException ex) { + // Best effort — stale inner class files are harmless + } + }); + } + } + } catch (IOException e) { + throw new UncheckedIOException("Failed to delete stale class file: " + classFile, e); + } + } + + /** + * Computes SHA-256 hashes for the given source files, using an mtime-first + * short-circuit: if a file's last-modified time matches the value stored in + * {@code prev}, its previously stored hash is reused without reading the + * file's content. This avoids redundant I/O on the common no-change case, + * particularly beneficial for large source trees. + * + * @param files the source files to process + * @param prev previous build's state (may be {@code null}) + * @param mtimes output map populated with each file's observed mtime (millis) + * @return map from file path string to SHA-256 content hash + */ + private static Map<String, String> hashSourceFiles( + List<Path> files, IncrementalState prev, Map<String, Long> mtimes) throws IOException { + var hashes = new LinkedHashMap<String, String>(); + for (Path file : files) { + String path = file.toString(); + BasicFileAttributes attrs = Files.readAttributes(file, BasicFileAttributes.class); + long mtime = attrs.lastModifiedTime().toMillis(); + mtimes.put(path, mtime); + + if (prev != null) { + var storedMtime = prev.getSourceMtime(path); + if (storedMtime.isPresent() && storedMtime.getAsLong() == mtime) { + String storedHash = prev.getSourceHash(path); + if (storedHash != null) { + // mtime unchanged — reuse stored hash, skip reading file content + hashes.put(path, storedHash); + continue; + } + } + } + + hashes.put(path, Sha256.hash(Files.readAllBytes(file))); + } + return hashes; + } + + // --- External classpath tracking --- + + private Set<String> checkExternalClasspathChanges() { + var currentIdentities = computeCurrentJarIdentities(); + var previousIdentities = previousState.getClasspathIdentities(); + state.setClasspathIdentities(currentIdentities); + + if (currentIdentities.equals(previousIdentities)) { + return Set.of(); + } + + // Determine which classpath entries changed (added, removed, or modified) + var changedEntries = new TreeSet<String>(); + for (var entry : currentIdentities.entrySet()) { + String prev = previousIdentities.get(entry.getKey()); + if (prev == null || !prev.equals(entry.getValue())) { + changedEntries.add(entry.getKey()); + } + } + for (String key : previousIdentities.keySet()) { + if (!currentIdentities.containsKey(key)) { + changedEntries.add(key); + } + } + + if (changedEntries.isEmpty()) { + return Set.of(); + } + + // Any external dependency changed — recompile all source files that reference + // types not defined in this module. Since we don't track which external type + // comes from which JAR, we conservatively invalidate all files that have any + // external dependency. + var externalTypes = previousState.getExternalDependencies(); + var invalidated = new TreeSet<String>(); + for (var entry : previousState.getTypes().entrySet()) { + String sf = entry.getValue().sourceFile(); + if (sf != null) { + for (String dep : entry.getValue().classDeps()) { + if (externalTypes.contains(dep)) { + invalidated.add(sf); + break; + } + } + } + } + return invalidated; + } + + private Map<String, String> computeCurrentJarIdentities() { + var identities = new LinkedHashMap<String, String>(); + if (classpathEntries == null) { + return identities; + } + for (Path entry : classpathEntries) { + String name = entry.getFileName().toString(); + if ((name.endsWith(".jar") || name.endsWith(".zip")) && Files.exists(entry)) { + try { + var attrs = Files.readAttributes(entry, BasicFileAttributes.class); + identities.put( Review Comment: _Claude Code on behalf of Guillaume Nodet_ Fixed: added Javadoc to computeCurrentJarIdentities() documenting that only JAR/ZIP entries are tracked and that reactor directory changes are detected by Maven's own dependency change detection. ########## src/main/java/org/apache/maven/plugin/compiler/ToolExecutor.java: ########## @@ -915,6 +919,241 @@ private static boolean removeFirsts(Deque<Path> paths, Integer count) { } } + /** + * Compiles using the dependency-graph incremental strategy. This method handles the full + * lifecycle: determining what to compile, running javac, cascading on changed classes, + * and persisting state. + * + * @param compiler the compiler + * @param configuration the options to give to the Java compiler + * @param mojo the MOJO for configuration access + * @throws IOException if an error occurred while reading or writing a file + * @throws MojoException if the compilation failed + */ + void compileWithGraphIncremental(JavaCompiler compiler, Options configuration, AbstractCompilerMojo mojo) + throws IOException { + var graphBuild = new GraphIncrementalBuild(outputDirectory); + + // Collect annotation processor path for processor classification + var processorPaths = new ArrayList<Path>(); + for (var entry : dependencies.entrySet()) { + if (entry.getKey() instanceof JavaPathType type) { + var location = type.location(); + if (location.isPresent() + && (location.get() == StandardLocation.ANNOTATION_PROCESSOR_PATH + || location.get() == StandardLocation.ANNOTATION_PROCESSOR_MODULE_PATH)) { + processorPaths.addAll(entry.getValue()); + } + } + } + if (!processorPaths.isEmpty()) { + graphBuild.setProcessorPath(processorPaths); + } + + // Collect classpath entries for external dependency tracking + var classpathEntries = new ArrayList<Path>(); + var reactorModulePaths = new LinkedHashSet<Path>(); + for (var entry : dependencies.entrySet()) { + if (entry.getKey() instanceof JavaPathType type) { + var location = type.location(); + if (location.isPresent() && location.get() == StandardLocation.CLASS_PATH) { + for (Path p : entry.getValue()) { + classpathEntries.add(p); + if (Files.isDirectory(p)) { + reactorModulePaths.add(p); + } + } + } + } + } + if (!classpathEntries.isEmpty()) { + graphBuild.setClasspathEntries(classpathEntries); + } + if (!reactorModulePaths.isEmpty()) { + graphBuild.setReactorModulePaths(reactorModulePaths); + } + + // Hash module-info-patch.maven files for config change detection + graphBuild.setConfigHash(computeConfigHash(configuration)); + + // Collect all source file paths + var allSourcePaths = new ArrayList<Path>(); + for (SourceFile sf : sourceFiles) { + allSourcePaths.add(sf.file); + } + + Set<Path> toCompile = graphBuild.initialize(allSourcePaths); + if (toCompile.isEmpty()) { + logger.info("Nothing to compile - all classes are up to date (graph strategy)."); + graphBuild.finish(); + return; + } + + logger.info( + graphBuild.isFullBuild() + ? "Compiling " + toCompile.size() + " source file(s) (graph: full build)." + : "Compiling " + toCompile.size() + " source file(s) (graph: incremental)."); + if (mojo.showCompilationChanges && graphBuild.getRebuildCause() != null) { + logger.info("Rebuild cause: " + graphBuild.getRebuildCause()); + for (Path f : toCompile) { + logger.info(" " + f); + } + } Review Comment: _Claude Code on behalf of Guillaume Nodet_ Fixed: added explanatory comment documenting why the field mutation pattern is used and that the finally block guarantees restoration. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
