Fix message when building because of a clean state

src/main/java/org/apache/maven/plugin/compiler/AbstractCompilerMojo.java

@@ -933,30 +933,35 @@ public void execute() throws MojoExecutionException, CompilationFailureException
                 incrementalBuildHelperRequest = new IncrementalBuildHelperRequest().inputFiles(sources);
 
                 // Strategies used to detect modifications.
-                String immutableOutputFile = (compiler.getCompilerOutputStyle()
-                                        .equals(CompilerOutputStyle.ONE_OUTPUT_FILE_FOR_ALL_INPUT_FILES)
-                                && !canUpdateTarget)
-                        ? "immutable single output file"
-                        : null;
-                String dependencyChanged = isDependencyChanged() ? "changed dependency" : null;
-                String sourceChanged = isSourceChanged(compilerConfiguration, compiler) ? "changed source code" : null;
-                String inputFileTreeChanged = hasInputFileTreeChanged(incrementalBuildHelper, sources)
-                        ? "added or removed source files"
-                        : null;
-
-                // Get the first cause for the rebuild compilation detection.
-                String cause = Stream.of(immutableOutputFile, dependencyChanged, sourceChanged, inputFileTreeChanged)
-                        .filter(Objects::nonNull)
-                        .findFirst()
-                        .orElse(null);
-
-                if (cause != null) {
-                    getLog().info("Recompiling the module because of "
-                            + MessageUtils.buffer().strong(cause) + ".");
-                    compilerConfiguration.setSourceFiles(sources);
-                } else {
-                    getLog().info("Nothing to compile - all classes are up to date.");
-                    return;
+                boolean cleanState = isCleanState(incrementalBuildHelper);
+                if (!cleanState) {
+                    String immutableOutputFile = (compiler.getCompilerOutputStyle()
+                                            .equals(CompilerOutputStyle.ONE_OUTPUT_FILE_FOR_ALL_INPUT_FILES)
+                                    && !canUpdateTarget)
+                            ? "immutable single output file"
+                            : null;
+                    String dependencyChanged = isDependencyChanged() ? "changed dependency" : null;
+                    String sourceChanged =
+                            isSourceChanged(compilerConfiguration, compiler) ? "changed source code" : null;
+                    String inputFileTreeChanged = hasInputFileTreeChanged(incrementalBuildHelper, sources)
+                            ? "added or removed source files"
+                            : null;
+
+                    // Get the first cause for the rebuild compilation detection.
+                    String cause = Stream.of(
+                                    immutableOutputFile, dependencyChanged, sourceChanged, inputFileTreeChanged)
+                            .filter(Objects::nonNull)
+                            .findFirst()
+                            .orElse(null);
+
+                    if (cause != null) {
+                        getLog().info("Recompiling the module because of "
+                                + MessageUtils.buffer().strong(cause) + ".");
+                        compilerConfiguration.setSourceFiles(sources);
+                    } else {
+                        getLog().info("Nothing to compile - all classes are up to date.");
+                        return;
+                    }
                 }
             } catch (CompilerException e) {
                 throw new MojoExecutionException("Error while computing stale sources.", e);
@@ -1591,6 +1596,22 @@ private static List<String> removeEmptyCompileSourceRoots(List<String> compileSo
         return newCompileSourceRootsList;
     }
 
+    /**
+     *
+     */
+    protected boolean isCleanState(IncrementalBuildHelper ibh) {
+        Path mojoConfigBase;
+        try {
+            mojoConfigBase = ibh.getMojoStatusDirectory().toPath();
+        } catch (MojoExecutionException e) {
+            // we cannot get the mojo status dir, so don't do anything beside logging
+            getLog().warn("Error reading mojo status directory.");
+            return false;
+        }
+        Path mojoConfigFile = mojoConfigBase.resolve(INPUT_FILES_LST_FILENAME);
+        return !Files.exists(mojoConfigFile);
+    }
+
     /**
      * We just compare the timestamps of all local dependency files (inter-module dependency classpath) and the own
      * generated classes and if we got a file which is &gt;= the build-started timestamp, then we caught a file which