[Core] Rewrite # language: tl to # language: te

With cucumber/common#1238 the iso code of Telugu was fixed from `tl` to `te`.
To ensure this does not break Cucumber-JVM until it has gone through a
deprecation cycle we rewrite ``# language: tl` to `# language: te` and warn
about the deprecation.

core/src/main/java/io/cucumber/core/feature/Encoding.java → core/src/main/java/io/cucumber/core/feature/EncodingParser.java

@@ -1,5 +1,6 @@
 package io.cucumber.core.feature;
 
+import io.cucumber.core.exception.CucumberException;
 import io.cucumber.core.resource.Resource;
 
 import java.io.BufferedReader;
@@ -13,17 +14,18 @@
 import static java.util.Locale.ROOT;
 
 /**
- * Utilities for reading the encoding of a file.
+ * Parser for the {@code # encoding: <encoding> } header. Will reload the file
+ * in the specified encoding if not UTF-8.
  */
-final class Encoding {
+final class EncodingParser {
 
     private static final Pattern COMMENT_OR_EMPTY_LINE_PATTERN = Pattern.compile("^\\s*#|^\\s*$");
     private static final Pattern ENCODING_PATTERN = Pattern.compile("^\\s*#\\s*encoding\\s*:\\s*([0-9a-zA-Z\\-]+)",
         Pattern.CASE_INSENSITIVE);
     private static final String DEFAULT_ENCODING = UTF_8.name();
     private static final String UTF_8_BOM = "\uFEFF";
 
-    static String readFile(Resource resource) throws RuntimeException, IOException {
+    String parse(Resource resource) {
         String source = read(resource, DEFAULT_ENCODING);
         // Remove UTF8 BOM encoded in first bytes
         if (source.startsWith(UTF_8_BOM)) {
@@ -36,7 +38,7 @@ static String readFile(Resource resource) throws RuntimeException, IOException {
         return source;
     }
 
-    private static String read(Resource resource, String encoding) throws IOException {
+    private static String read(Resource resource, String encoding) {
         char[] buffer = new char[2 * 1024];
         final StringBuilder out = new StringBuilder();
         try (
@@ -47,6 +49,8 @@ private static String read(Resource resource, String encoding) throws IOExceptio
             while ((read = reader.read(buffer, 0, buffer.length)) > 0) {
                 out.append(buffer, 0, read);
             }
+        } catch (IOException e) {
+            throw new CucumberException("Failed to read resource:" + resource.getUri(), e);
         }
         return out.toString();
     }

core/src/main/java/io/cucumber/core/feature/FeatureParser.java

@@ -1,10 +1,8 @@
 package io.cucumber.core.feature;
 
-import io.cucumber.core.exception.CucumberException;
 import io.cucumber.core.gherkin.Feature;
 import io.cucumber.core.resource.Resource;
 
-import java.io.IOException;
 import java.net.URI;
 import java.util.ArrayList;
 import java.util.Collections;
@@ -21,6 +19,9 @@
 
 public final class FeatureParser {
 
+    private final EncodingParser encodingParser = new EncodingParser();
+    private final LanguageParser languageParser = new LanguageParser();
+
     private final Supplier<UUID> idGenerator;
 
     public FeatureParser(Supplier<UUID> idGenerator) {
@@ -30,7 +31,10 @@ public FeatureParser(Supplier<UUID> idGenerator) {
     public Optional<Feature> parseResource(Resource resource) {
         requireNonNull(resource);
         URI uri = resource.getUri();
-        String source = read(resource);
+
+        String encodingParsed = encodingParser.parse(resource);
+        String source = languageParser.parse(encodingParsed);
+
         ServiceLoader<io.cucumber.core.gherkin.FeatureParser> services = ServiceLoader
                 .load(io.cucumber.core.gherkin.FeatureParser.class);
         Iterator<io.cucumber.core.gherkin.FeatureParser> iterator = services.iterator();
@@ -43,12 +47,4 @@ public Optional<Feature> parseResource(Resource resource) {
         return Collections.max(parser, version).parse(uri, source, idGenerator);
     }
 
-    private static String read(Resource resource) {
-        try {
-            return Encoding.readFile(resource);
-        } catch (IOException e) {
-            throw new CucumberException("Failed to read resource:" + resource.getUri(), e);
-        }
-    }
-
 }

core/src/main/java/io/cucumber/core/feature/LanguageParser.java

@@ -0,0 +1,26 @@
+package io.cucumber.core.feature;
+
+import io.cucumber.core.logging.Logger;
+import io.cucumber.core.logging.LoggerFactory;
+
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * Parser for the {@code # language: <iso-code> } header. Replaces changed ISO
+ * codes for backwards compatibility.
+ */
+class LanguageParser {
+    private static final Logger log = LoggerFactory.getLogger(FeatureParser.class);
+    private static final Pattern LANGUAGE_PATTERN = Pattern.compile("^(\\s*#\\s*language\\s*:\\s*)tl");
+
+    String parse(String feature) {
+        Matcher matcher = LANGUAGE_PATTERN.matcher(feature);
+        if (matcher.find()) {
+            log.warn(
+                () -> "The ISO 639-1 code for Telugu was changed from tl to te. Please use '# language: te' in your feature files.");
+            return matcher.replaceFirst("$1te");
+        }
+        return feature;
+    }
+}

core/src/test/java/io/cucumber/core/feature/EncodingParserTest.java

@@ -0,0 +1,44 @@
+package io.cucumber.core.feature;
+
+import io.cucumber.core.resource.Resource;
+import org.junit.jupiter.api.Test;
+
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URI;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+
+class EncodingParserTest {
+
+    private final EncodingParser parser = new EncodingParser();
+
+    @Test
+    void test_utf8_bom_encode() throws RuntimeException, IOException {
+        Resource resource = resource("src/test/resources/io/cucumber/core/feature/UTF_8_BOM_Encoded.feature");
+        assertFalse(parser.parse(resource).startsWith("\uFEFF"), "UTF-8 BOM encoding not removed.");
+    }
+
+    @Test
+    void test_utf8_encode() throws RuntimeException, IOException {
+        Resource resource = resource("src/test/resources/io/cucumber/core/feature/UTF_8_Encoded.feature");
+        assertFalse(parser.parse(resource).startsWith("\uFEFF"), "UTF-8 BOM encoding should not be present.");
+    }
+
+    private Resource resource(String name) {
+        Resource resource = new Resource() {
+            @Override
+            public URI getUri() {
+                return null;
+            }
+
+            @Override
+            public InputStream getInputStream() throws IOException {
+
+                return new FileInputStream(name);
+            }
+        };
+        return resource;
+    }
+}

core/src/test/java/io/cucumber/core/feature/FeatureParserTest.java

@@ -0,0 +1,52 @@
+package io.cucumber.core.feature;
+
+import io.cucumber.core.gherkin.Feature;
+import io.cucumber.core.resource.Resource;
+import org.hamcrest.CoreMatchers;
+import org.hamcrest.MatcherAssert;
+import org.junit.jupiter.api.Test;
+
+import java.io.ByteArrayInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.net.URI;
+import java.nio.charset.StandardCharsets;
+import java.util.Optional;
+import java.util.UUID;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.CoreMatchers.not;
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.collection.IsEmptyIterable.emptyIterable;
+import static org.junit.jupiter.api.Assertions.*;
+
+class FeatureParserTest {
+
+    FeatureParser featureParser = new FeatureParser(UUID::randomUUID);
+
+    @Test
+    void renamesDeprecatedTeToTl() {
+        Feature feature = featureParser.parseResource(resource("" +
+                "# language: tl\n" +
+                "గుణము: Test feature\n" +
+                "  ఉదాహరణ: Test scenario\n" +
+                "     చెప్పబడినది some text\n")).get();
+        assertThat(feature.getPickles().get(0).getLanguage(), is("te"));
+    }
+
+    private Resource resource(String feature) {
+        return new Resource() {
+            @Override
+            public URI getUri() {
+                return URI.create("file:test.feature");
+            }
+
+            @Override
+            public InputStream getInputStream() {
+                return new ByteArrayInputStream(feature.getBytes(UTF_8));
+            }
+        };
+    }
+
+}