JetBrains/intellij-community · error · CantRunException

IDEA cannot generate Javadoc as module-source-path cannot…

Error message

IDEA cannot generate Javadoc as module-source-path cannot be evaluated

What it means

With JDK 9+ and more than one module, the runner writes a --module-source-path argument computed by computeModuleSourcePath from the per-module source roots (e.g. 'mod1/*=dir1;mod2/*=dir2' patterns). If that computation returns null — roots cannot be mapped to the expected layout — CantRunException('module-source-path cannot be evaluated') aborts. This is an internal layout-analysis failure: typically a module's content roots do not fit the pattern the algorithm supports.

Solutions

1. Check that every module in the scope has exactly one properly marked production Sources Root containing its module-info.java.
2. Re-import the project (Gradle/Maven refresh) to regenerate a canonical content-root layout.
3. If one module has an exotic layout, generate javadoc module-by-module with single-module scopes to isolate the offender.

// Each module must have exactly one marked production source root containing module-info.java
for (Module m : modules) {
  List<VirtualFile> roots = OrderEnumerator.orderEntries(m).getSourcePathsList... // or ModuleRootManager.getSourceRoots()
  if (roots.stream().noneMatch(r -> r.findChild(PsiJavaModule.MODULE_INFO_FILE) != null)) { notify("Module " + m.getName() + " layout prevents module-source-path"); return; }
}

When it happens

Trigger: Multi-module JPMS javadoc generation where a module's source roots are missing, duplicated in an ambiguous way, or arranged (e.g. several production roots per module) such that computeModuleSourcePath cannot construct the module-source-path string.

Common situations: Modules whose source root was deleted or is invalid; Gradle/Maven imports producing unusual content-root layouts; modules included via the javadoc scope without any marked source root.

Related errors

• IDEA cannot generate Javadoc as modules
• No Java sources found in the selected scope
• Cannot generate JavaDoc - no Java SDK is configured for the…
• Cannot set package name for module declarations
• psi.error.attempt.to.edit.class.file

AI-assisted analysis of JetBrains/intellij-community@be881553f2 (2026-08-14). Data as JSON: /api/errors/bbb5107df66a1478. Report an issue: GitHub.

Appendix: source

Thrown at java/java-impl/src/com/intellij/javadoc/JavadocGeneratorRunProfile.java:298

            parameters.add("--source", String.valueOf(languageLevel.feature()));
            break;
          }
        }
      }

      File argsFile = createTempArgsFile();
      List<VirtualFile> sourceRoots = findSourceRoots(modules);
      List<VirtualFile> classRoots = findClassRoots(modules, jdk);

      Charset cs = CharsetToolkit.getPlatformCharset();
      try (PrintWriter writer = new PrintWriter(new OutputStreamWriter(new FileOutputStream(argsFile), cs))) {
        if (sourceRoots.size() + classRoots.size() > 0) {
          if (hasJavaModules && JavaSdkUtil.isJdkAtLeast(jdk, JavaSdkVersion.JDK_1_9)) {
            if (modules.size() > 1) {
              writer.println("--module-source-path");
              String moduleSourcePath = computeModuleSourcePath(moduleDescriptors);
              if (moduleSourcePath == null) {
                throw new CantRunException(JavaBundle.message("javadoc.gen.error.module.source.path.is.not.evaluated"));
              }
              writer.println(StringUtil.wrapWithDoubleQuote(moduleSourcePath));
            }
            else if (!sourceRoots.isEmpty()) {
              String path = sourceRoots.stream().map(MyJavaCommandLineState::localPath).collect(Collectors.joining(File.pathSeparator));
              writer.println("--source-path");
              writer.println(StringUtil.wrapWithDoubleQuote(path));
            }

            if (!classRoots.isEmpty()) {
              String path = classRoots.stream().map(MyJavaCommandLineState::localPath).collect(Collectors.joining(File.pathSeparator));
              writer.println("--module-path");
              writer.println(StringUtil.wrapWithDoubleQuote(path));
            }
          }
          else {
            // placing source roots on a classpath is perfectly legal and allows generating correct Javadoc
            // when a module without a module-info.java file depends on another module that has one

View on GitHub (pinned to be881553f2)