Add input validation and improve error handling

.github/workflows/ci.yml

@@ -32,11 +32,14 @@ jobs:
 
       - name: Build with Maven
         run: ./mvnw -e --no-transfer-progress clean install
+        continue-on-error: false
 
       - name: Check for changes
         shell: bash
         run: |
-          git diff --exit-code || (
+          if ! git diff --exit-code; then
             echo "::error::Code changes detected - run './mvnw clean verify' locally"
+            echo "::error::Modified files:"
+            git diff --name-only
             exit 1
-          )
+          fi

rewrite.yml

@@ -1,4 +1,6 @@
-# mvn rewrite:run -Drewrite.activeRecipes=org.checkstyle.recipes.OpenRewriteRecipeBestPractices
+# OpenRewrite Configuration for Checkstyle Auto-Fix
+# Usage: mvn rewrite:run -Drewrite.activeRecipes=org.checkstyle.recipes.OpenRewriteRecipeBestPractices
+# This file defines recipes for automatically fixing Checkstyle violations and applying best practices.
 ---
 type: specs.openrewrite.org/v1beta/recipe
 name: org.checkstyle.recipes.OpenRewriteRecipeBestPractices
@@ -101,6 +103,11 @@ tags:
   - code-quality
 recipeList:
   - org.checkstyle.autofix.CheckstyleAutoFix:
+      # Path to Checkstyle violation report (XML or SARIF format)
+      # Ensure this file exists before running the recipe
       violationReportPath: "target/checkstyle/checkstyle-report.xml"
+      # Path or URL to Checkstyle configuration file
+      # Must be accessible and valid XML format
       configurationPath: "https://raw.githubusercontent.com/checkstyle/checkstyle/checkstyle-${checkstyle.version}/config/checkstyle-checks.xml"
+      # Optional: Path to properties file for Checkstyle configuration
       propertiesPath: "config/checkstyle.properties"

src/main/java/org/checkstyle/autofix/CheckstyleAutoFix.java

@@ -85,6 +85,7 @@ public String getPropertiesPath() {
 
     @Override
     public List<Recipe> getRecipeList() {
+        validateInputs();
         final ReportParser reportParser = createReportParser(getViolationReportPath());
         final List<CheckstyleViolation> violations = reportParser
                 .parse(Path.of(getViolationReportPath()));
@@ -94,6 +95,17 @@ public List<Recipe> getRecipeList() {
         return CheckstyleRecipeRegistry.getRecipes(violations, configuration);
     }
 
+    private void validateInputs() {
+        if (violationReportPath == null || violationReportPath.trim().isEmpty()) {
+            throw new IllegalArgumentException(
+                    "Violation report path cannot be null or empty");
+        }
+        if (configurationPath == null || configurationPath.trim().isEmpty()) {
+            throw new IllegalArgumentException(
+                    "Configuration path cannot be null or empty");
+        }
+    }
+
     private ReportParser createReportParser(String path) {
         final ReportParser result;
         if (path.endsWith(".xml")) {

src/main/java/org/checkstyle/autofix/parser/ConfigurationLoader.java

@@ -71,16 +71,25 @@ private static Map<String, String> getProperties(Configuration config) {
 
     public static Map<CheckstyleCheck, CheckConfiguration> loadConfiguration(
             String checkstyleConfigurationPath, String propFile) {
+        if (checkstyleConfigurationPath == null || checkstyleConfigurationPath.trim().isEmpty()) {
+            throw new IllegalArgumentException(
+                    "Checkstyle configuration path cannot be null or empty");
+        }
+
         Properties props = new Properties();
         if (propFile == null) {
             props = System.getProperties();
         }
         else {
+            if (propFile.trim().isEmpty()) {
+                throw new IllegalArgumentException("Properties file path cannot be empty");
+            }
             try (FileInputStream input = new FileInputStream(propFile)) {
                 props.load(input);
             }
             catch (IOException exception) {
-                throw new IllegalStateException("Failed to read: " + propFile, exception);
+                throw new IllegalStateException("Failed to read properties file: "
+                        + propFile, exception);
             }
         }
 

src/main/java/org/checkstyle/autofix/parser/SarifReportParser.java

@@ -46,13 +46,23 @@ public SarifReportParser() {
 
     @Override
     public List<CheckstyleViolation> parse(Path reportPath) {
+        if (reportPath == null) {
+            throw new IllegalArgumentException("Report path cannot be null");
+        }
+        if (!reportPath.toFile().exists()) {
+            throw new IllegalArgumentException("Report file does not exist: " + reportPath);
+        }
+
         final SarifSchema210 report;
         try {
             report = parser.fromFile(reportPath);
         }
         catch (IOException exception) {
             throw new IllegalArgumentException("Failed to parse report: " + reportPath, exception);
         }
+        if (report == null || report.getRuns() == null || report.getRuns().isEmpty()) {
+            throw new IllegalArgumentException("SARIF report is empty or invalid: " + reportPath);
+        }
         final List<CheckstyleViolation> result = new ArrayList<>();
         for (final Run run: report.getRuns()) {
             if (run.getResults() != null) {
@@ -68,11 +78,24 @@ public List<CheckstyleViolation> parse(Path reportPath) {
     }
 
     private CheckstyleViolation createViolation(CheckstyleCheck check, Result result) {
+        if (result.getLevel() == null) {
+            throw new IllegalStateException("Result level is missing");
+        }
+        if (result.getMessage() == null || result.getMessage().getText() == null) {
+            throw new IllegalStateException("Result message is missing");
+        }
+        if (result.getLocations() == null || result.getLocations().isEmpty()) {
+            throw new IllegalStateException("Result locations are missing");
+        }
+
         final String severity = result.getLevel().name();
         final String message = result.getMessage().getText();
         final PhysicalLocation location = result.getLocations().get(0).getPhysicalLocation();
         final Path filePath = getFilePath(location);
         final Region region = location.getRegion();
+        if (region == null || region.getStartLine() == null) {
+            throw new IllegalStateException("Region or start line is missing");
+        }
         final int line = region.getStartLine();
         final Optional<Integer> columnMaybe = Optional.ofNullable(region.getStartColumn());
         return columnMaybe.map(column -> {

src/main/java/org/checkstyle/autofix/parser/XmlReportParser.java

@@ -56,6 +56,12 @@ public class XmlReportParser implements ReportParser {
 
     @Override
     public List<CheckstyleViolation> parse(Path xmlPath) {
+        if (xmlPath == null) {
+            throw new IllegalArgumentException("XML path cannot be null");
+        }
+        if (!xmlPath.toFile().exists()) {
+            throw new IllegalArgumentException("XML file does not exist: " + xmlPath);
+        }
 
         final List<CheckstyleViolation> result = new ArrayList<>();
 
@@ -108,6 +114,9 @@ private String parseFileTag(StartElement startElement) {
                 break;
             }
         }
+        if (fileName == null || fileName.trim().isEmpty()) {
+            throw new IllegalStateException("File name attribute is missing or empty");
+        }
         return fileName;
     }