Fix #460 Delay classpath resolution to the compile phase (#461)

- Delay the classpath computation
- Add a ValidateClassPathMojo if earlier validation/computation is desired

tycho-compiler-plugin/src/main/java/org/eclipse/tycho/compiler/AbstractOsgiCompilerMojo.java

@@ -69,7 +69,6 @@
 import org.eclipse.tycho.classpath.JavaCompilerConfiguration;
 import org.eclipse.tycho.classpath.SourcepathEntry;
 import org.eclipse.tycho.core.BundleProject;
-import org.eclipse.tycho.core.TychoConstants;
 import org.eclipse.tycho.core.TychoProject;
 import org.eclipse.tycho.core.dotClasspath.JREClasspathEntry;
 import org.eclipse.tycho.core.dotClasspath.M2ClasspathVariable;
@@ -662,10 +661,9 @@ private void configureBootclasspathAccessRules(CompilerConfiguration compilerCon
         }
     }
 
-    @SuppressWarnings("unchecked")
     private List<AccessRule> getStrictBootClasspathAccessRules() throws MojoExecutionException {
-        return (List<AccessRule>) DefaultReactorProject.adapt(project)
-                .getContextValue(TychoConstants.CTX_ECLIPSE_PLUGIN_STRICT_BOOTCLASSPATH_ACCESSRULES);
+        return ((OsgiBundleProject) getBundleProject()).getBundleClassPath(DefaultReactorProject.adapt(project))
+                .getStrictBootClasspathAccessRules();
     }
 
     private void configureJavaHome(CompilerConfiguration compilerConfiguration) throws MojoExecutionException {

tycho-compiler-plugin/src/main/java/org/eclipse/tycho/compiler/ValidateClassPathMojo.java

@@ -0,0 +1,51 @@
+/*******************************************************************************
+ * Copyright (c) 2021 Christoph Läubrich and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     Christoph Läubrich - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.tycho.compiler;
+
+import java.util.Map;
+
+import org.apache.maven.plugin.AbstractMojo;
+import org.apache.maven.plugin.MojoExecutionException;
+import org.apache.maven.plugin.MojoFailureException;
+import org.apache.maven.plugins.annotations.Component;
+import org.apache.maven.plugins.annotations.LifecyclePhase;
+import org.apache.maven.plugins.annotations.Mojo;
+import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.plugins.annotations.ResolutionScope;
+import org.apache.maven.project.MavenProject;
+import org.eclipse.tycho.core.TychoProject;
+import org.eclipse.tycho.core.osgitools.DefaultReactorProject;
+import org.eclipse.tycho.core.osgitools.OsgiBundleProject;
+
+/**
+ * This mojo could be added to a build if validation of the classpath is desired before the
+ * compile-phase.
+ */
+@Mojo(name = "validate-classpath", defaultPhase = LifecyclePhase.VALIDATE, requiresDependencyResolution = ResolutionScope.COMPILE, threadSafe = true)
+public class ValidateClassPathMojo extends AbstractMojo {
+
+    @Parameter(property = "project", readonly = true)
+    private MavenProject project;
+
+    @Component(role = TychoProject.class)
+    private Map<String, TychoProject> projectTypes;
+
+    @Override
+    public void execute() throws MojoExecutionException, MojoFailureException {
+
+        TychoProject projectType = projectTypes.get(project.getPackaging());
+        if (projectType instanceof OsgiBundleProject) {
+            OsgiBundleProject bundleProject = (OsgiBundleProject) projectType;
+            bundleProject.getClasspath(DefaultReactorProject.adapt(project));
+        }
+    }
+
+}

tycho-core/src/main/java/org/eclipse/tycho/core/TychoConstants.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2008, 2014 Sonatype Inc. and others.
+ * Copyright (c) 2008, 2021 Sonatype Inc. and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -24,15 +24,8 @@ public interface TychoConstants {
      */
     static final String CTX_TEST_DEPENDENCY_ARTIFACTS = CTX_BASENAME + "/testDependencyArtifacts";
     static final String CTX_ECLIPSE_PLUGIN_PROJECT = CTX_BASENAME + "/eclipsePluginProject";
-    static final String CTX_ECLIPSE_PLUGIN_CLASSPATH = CTX_BASENAME + "/eclipsePluginClasspath";
-    /**
-     * Stores test-specific classpath (usually derived from .classpath)
-     */
     static final String CTX_ECLIPSE_PLUGIN_TEST_CLASSPATH = CTX_BASENAME + "/eclipsePluginTestClasspath";
-    static final String CTX_ECLIPSE_PLUGIN_STRICT_BOOTCLASSPATH_ACCESSRULES = CTX_BASENAME
-            + "/eclipsePluginStrictBootclasspathAccessRules";
-    static final String CTX_ECLIPSE_PLUGIN_BOOTCLASSPATH_EXTRA_ACCESSRULES = CTX_BASENAME
-            + "/eclipsePluginBootclasspathExtraAccessRules";
+
     static final String CTX_MERGED_PROPERTIES = CTX_BASENAME + "/mergedProperties";
     static final String CTX_TARGET_PLATFORM_CONFIGURATION = CTX_BASENAME + "/targetPlatformConfiguration";
     static final String CTX_EXECUTION_ENVIRONMENT_CONFIGURATION = CTX_BASENAME + "/executionEnvironmentConfiguration";

tycho-core/src/main/java/org/eclipse/tycho/core/osgitools/AbstractTychoProject.java

@@ -1,12 +1,13 @@
 /*******************************************************************************
- * Copyright (c) 2008, 2012 Sonatype Inc. and others.
+ * Copyright (c) 2008, 2021 Sonatype Inc. and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *    Sonatype Inc. - initial API and implementation
+ *    Christoph Läubrich - Issue #460 - Delay classpath resolution to the compile phase 
  *******************************************************************************/
 package org.eclipse.tycho.core.osgitools;
 
@@ -73,10 +74,6 @@ public void setupProject(MavenSession session, MavenProject project) {
     public void checkForMissingDependencies(ReactorProject project) {
     }
 
-    public void resolveClassPath(MavenSession session, MavenProject project) {
-        // do nothing by default
-    }
-
     protected TargetEnvironment[] getEnvironments(ReactorProject project, TargetEnvironment environment) {
         if (environment != null) {
             return new TargetEnvironment[] { environment };

tycho-core/src/main/java/org/eclipse/tycho/core/osgitools/BundleClassPath.java

@@ -0,0 +1,44 @@
+/*******************************************************************************
+ * Copyright (c) 2021 Christoph Läubrich and others.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the Eclipse Public License v1.0
+ * which accompanies this distribution, and is available at
+ * http://www.eclipse.org/legal/epl-v10.html
+ *
+ * Contributors:
+ *     Christoph Läubrich - initial API and implementation
+ *******************************************************************************/
+package org.eclipse.tycho.core.osgitools;
+
+import java.util.Collections;
+import java.util.List;
+
+import org.eclipse.tycho.classpath.ClasspathEntry;
+import org.eclipse.tycho.classpath.ClasspathEntry.AccessRule;
+
+public class BundleClassPath {
+
+    private List<ClasspathEntry> classpath;
+    private List<AccessRule> strictBootClasspathAccessRules;
+    private List<AccessRule> bootClasspathExtraAccessRules;
+
+    BundleClassPath(List<ClasspathEntry> classpath, List<AccessRule> strictBootClasspathAccessRules,
+            List<AccessRule> bootClasspathExtraAccessRules) {
+        this.classpath = Collections.unmodifiableList(classpath);
+        this.strictBootClasspathAccessRules = Collections.unmodifiableList(strictBootClasspathAccessRules);
+        this.bootClasspathExtraAccessRules = Collections.unmodifiableList(bootClasspathExtraAccessRules);
+    }
+
+    public List<ClasspathEntry> getClasspathEntries() {
+        return classpath;
+    }
+
+    public List<AccessRule> getStrictBootClasspathAccessRules() {
+        return strictBootClasspathAccessRules;
+    }
+
+    public List<AccessRule> getExtraBootClasspathAccessRules() {
+        return bootClasspathExtraAccessRules;
+    }
+
+}

tycho-core/src/main/java/org/eclipse/tycho/core/osgitools/OsgiBundleProject.java

@@ -9,6 +9,7 @@
  *    Sonatype Inc. - initial API and implementation
  *    Christoph Läubrich -  [Bug 572416] Tycho does not understand "additional.bundles" directive in build.properties
  *                          [Bug 572416] Compile all source folders contained in .classpath
+ *                          [Issue #460] Delay classpath resolution to the compile phase 
  *******************************************************************************/
 package org.eclipse.tycho.core.osgitools;
 
@@ -23,6 +24,7 @@
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Properties;
 import java.util.Set;
 import java.util.regex.Matcher;
@@ -89,7 +91,11 @@
 @Component(role = TychoProject.class, hint = PackagingType.TYPE_ECLIPSE_PLUGIN)
 public class OsgiBundleProject extends AbstractTychoProject implements BundleProject {
 
-    private static final String CTX_ARTIFACT_KEY = TychoConstants.CTX_BASENAME + "/osgiBundle/artifactKey";
+    private static final String CTX_OSGI_BUNDLE_BASENAME = TychoConstants.CTX_BASENAME + "/osgiBundle";
+    private static final String CTX_ARTIFACT_KEY = CTX_OSGI_BUNDLE_BASENAME + "/artifactKey";
+    private static final String CTX_MAVEN_SESSION = CTX_OSGI_BUNDLE_BASENAME + "/mavenSession";
+    private static final String CTX_MAVEN_PROJECT = CTX_OSGI_BUNDLE_BASENAME + "/mavenProject";
+    private static final String CTX_CLASSPATH = CTX_OSGI_BUNDLE_BASENAME + "/classPath";
 
     @Requirement
     private BundleReader bundleReader;
@@ -171,7 +177,20 @@ public ArtifactKey getArtifactKey(ReactorProject project) {
     @Override
     public void setupProject(MavenSession session, MavenProject project) {
         ArtifactKey key = readArtifactKey(project.getBasedir());
-        DefaultReactorProject.adapt(project).setContextValue(CTX_ARTIFACT_KEY, key);
+        ReactorProject reactorProject = DefaultReactorProject.adapt(project);
+        reactorProject.setContextValue(CTX_ARTIFACT_KEY, key);
+        reactorProject.setContextValue(CTX_MAVEN_SESSION, session);
+        reactorProject.setContextValue(CTX_MAVEN_PROJECT, project);
+    }
+
+    private MavenSession getMavenSession(ReactorProject reactorProject) {
+        return Objects.requireNonNull((MavenSession) reactorProject.getContextValue(CTX_MAVEN_SESSION),
+                "Project not setup correctly");
+    }
+
+    private MavenProject getMavenProject(ReactorProject reactorProject) {
+        return Objects.requireNonNull((MavenProject) reactorProject.getContextValue(CTX_MAVEN_PROJECT),
+                "Project not setup correctly");
     }
 
     public ArtifactKey readArtifactKey(File location) {
@@ -188,8 +207,8 @@ private OsgiManifest getManifest(ReactorProject project) {
         return bundleReader.loadManifest(project.getBasedir());
     }
 
-    @Override
-    public void resolveClassPath(MavenSession session, MavenProject project) {
+    private BundleClassPath resolveClassPath(MavenSession session, MavenProject project) {
+        logger.info("Resolving class path of " + project.getName() + "...");
         ReactorProject reactorProject = DefaultReactorProject.adapt(project);
         DependencyArtifacts artifacts = getDependencyArtifacts(reactorProject);
 
@@ -247,13 +266,10 @@ public void resolveClassPath(MavenSession session, MavenProject project) {
         List<File> projectClasspath = getThisProjectClasspath(artifact, reactorProject);
         classpath.add(new DefaultClasspathEntry(reactorProject, artifact.getKey(), projectClasspath, null));
 
-        reactorProject.setContextValue(TychoConstants.CTX_ECLIPSE_PLUGIN_CLASSPATH, classpath);
-        reactorProject.setContextValue(TychoConstants.CTX_ECLIPSE_PLUGIN_STRICT_BOOTCLASSPATH_ACCESSRULES,
-                strictBootClasspathAccessRules);
-        reactorProject.setContextValue(TychoConstants.CTX_ECLIPSE_PLUGIN_BOOTCLASSPATH_EXTRA_ACCESSRULES,
-                dependencyComputer.computeBootClasspathExtraAccessRules(state));
+        List<AccessRule> bootClasspathExtraAccessRules = dependencyComputer.computeBootClasspathExtraAccessRules(state);
 
         addPDESourceRoots(project);
+        return new BundleClassPath(classpath, strictBootClasspathAccessRules, bootClasspathExtraAccessRules);
     }
 
     private Collection<ClasspathEntry> computeExtraTestClasspath(ReactorProject reactorProject) {
@@ -365,24 +381,22 @@ private void populateProperties(Properties mavenProjectProperties, EclipsePlugin
 
     @Override
     public List<ClasspathEntry> getClasspath(ReactorProject project) {
-        @SuppressWarnings("unchecked")
-        List<ClasspathEntry> classpath = (List<ClasspathEntry>) project
-                .getContextValue(TychoConstants.CTX_ECLIPSE_PLUGIN_CLASSPATH);
-        if (classpath == null) {
-            throw new IllegalStateException();
-        }
-        return classpath;
+        return getBundleClassPath(project).getClasspathEntries();
     }
 
     @Override
     public List<ClasspathEntry.AccessRule> getBootClasspathExtraAccessRules(ReactorProject project) {
-        @SuppressWarnings("unchecked")
-        List<ClasspathEntry.AccessRule> rules = (List<AccessRule>) project
-                .getContextValue(TychoConstants.CTX_ECLIPSE_PLUGIN_BOOTCLASSPATH_EXTRA_ACCESSRULES);
-        if (rules == null) {
-            throw new IllegalStateException();
+        return getBundleClassPath(project).getExtraBootClasspathAccessRules();
+    }
+
+    public synchronized BundleClassPath getBundleClassPath(ReactorProject project) {
+        Object contextValue = project.getContextValue(CTX_CLASSPATH);
+        if (contextValue instanceof BundleClassPath) {
+            return (BundleClassPath) contextValue;
         }
-        return rules;
+        BundleClassPath cp = resolveClassPath(getMavenSession(project), getMavenProject(project));
+        project.setContextValue(CTX_CLASSPATH, cp);
+        return cp;
     }
 
     /**
@@ -485,7 +499,8 @@ private void addExtraClasspathEntries(List<ClasspathEntry> classpath, ReactorPro
             if (entry instanceof LibraryClasspathEntry) {
                 LibraryClasspathEntry libraryClasspathEntry = (LibraryClasspathEntry) entry;
                 ArtifactKey projectKey = getArtifactKey(project);
-                classpath.add(new DefaultClasspathEntry(project, projectKey, Collections.singletonList(libraryClasspathEntry.getLibraryPath()), null));
+                classpath.add(new DefaultClasspathEntry(project, projectKey,
+                        Collections.singletonList(libraryClasspathEntry.getLibraryPath()), null));
             }
         }
     }

tycho-core/src/main/java/org/eclipse/tycho/core/resolver/DefaultTychoResolver.java

@@ -1,5 +1,5 @@
 /*******************************************************************************
- * Copyright (c) 2008, 2020 Sonatype Inc. and others.
+ * Copyright (c) 2008, 2021 Sonatype Inc. and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
@@ -8,6 +8,7 @@
  * Contributors:
  *    Sonatype Inc. - initial API and implementation
  *    Christoph Läubrich - Bug 532575
+ *    Christoph Läubrich - Issue #460 - Delay classpath resolution to the compile phase 
  *******************************************************************************/
 package org.eclipse.tycho.core.resolver;
 
@@ -169,9 +170,6 @@ public List<ArtifactKey> getExtraRequirements() {
                     Objects.requireNonNullElse(testDependencyArtifacts, new DefaultDependencyArtifacts()));
         }
 
-        logger.info("Resolving class path of " + project);
-        dr.resolveClassPath(session, project);
-
         resolver.injectDependenciesIntoMavenModel(project, dr, dependencyArtifacts, testDependencyArtifacts, logger);
 
         if (logger.isDebugEnabled() && DebugUtils.isDebugEnabled(session, project)) {