[MSHARED-1453] Canonicalize properties files

src/main/java/org/apache/maven/shared/archiver/PomPropertiesUtil.java

@@ -18,19 +18,18 @@
  */
 package org.apache.maven.shared.archiver;
 
-import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
-import java.io.PrintWriter;
-import java.io.StringReader;
-import java.io.StringWriter;
+import java.io.Writer;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Locale;
 import java.util.Properties;
+import java.util.Set;
 
 import org.apache.maven.api.Project;
 import org.apache.maven.api.Session;
@@ -61,36 +60,81 @@ private boolean sameContents(Properties props, Path file) throws IOException {
         return fileProps.equals(props);
     }
 
-    private void createPropertiesFile(Properties properties, Path outputFile, boolean forceCreation)
+    private void createPropertiesFile(Properties unsortedProperties, Path outputFile, boolean forceCreation)
             throws IOException {
         Path outputDir = outputFile.getParent();
         if (outputDir != null && !Files.isDirectory(outputDir)) {
             Files.createDirectories(outputDir);
         }
-        if (!forceCreation && sameContents(properties, outputFile)) {
+        if (!forceCreation && sameContents(unsortedProperties, outputFile)) {
             return;
         }
 
-        try (PrintWriter pw = new PrintWriter(outputFile.toFile(), StandardCharsets.ISO_8859_1.name());
-                StringWriter sw = new StringWriter()) {
-
-            properties.store(sw, null);
+        // For reproducible builds, sort the properties and drop comments.
+        // The java.util.Properties class doesn't guarantee order so we have
+        // to write the file using a Writer.
+        Set<String> propertyNames = unsortedProperties.stringPropertyNames();
+        List<String> sortedPropertyNames = new ArrayList<>(propertyNames);
+        Collections.sort(sortedPropertyNames);
+
+        try (Writer out = Files.newBufferedWriter(outputFile, StandardCharsets.ISO_8859_1)) {
+            for (String key : sortedPropertyNames) {
+                out.write(escapeKey(key));
+                out.write("=");
+                out.write(escapeValue(unsortedProperties.getProperty(key)));
+                out.write('\n');
+            }
+        }
+    }
 
-            List<String> lines = new ArrayList<>();
-            try (BufferedReader r = new BufferedReader(new StringReader(sw.toString()))) {
-                String line;
-                while ((line = r.readLine()) != null) {
-                    if (!line.startsWith("#")) {
-                        lines.add(line);
-                    }
-                }
+    private static String escapeKey(String s) {
+        StringBuilder sb = new StringBuilder(s.length());
+        for (char c : s.toCharArray()) {
+            if (Character.isWhitespace(c)
+                    || c == '#'
+                    || c == '!'
+                    || c == '='
+                    || c == ':'
+                    || c == '\\') { // backslash escape
+                sb.append('\\');
+                sb.append(c);
+            } else if (c < 128) { // ASCII
+                sb.append(c);
+            } else {
+                sb.append(hexEncode(c));
             }
+        }
+        return sb.toString();
+    }
 
-            Collections.sort(lines);
-            for (String l : lines) {
-                pw.println(l);
+    private static String escapeValue(String s) {
+        StringBuilder sb = new StringBuilder(s.length());
+        boolean atBeginning = true;
+        for (char c : s.toCharArray()) {
+            if (Character.isWhitespace(c) && atBeginning) {
+                sb.append('\\');
+                sb.append(c);
+            } else if (c == '#' || c == '!' || c == '=' || c == ':' || c == '\\') { // backslash escape
+                sb.append('\\');
+                sb.append(c);
+                atBeginning = false;
+            } else if (c < 128) { // ASCII
+                sb.append(c);
+                atBeginning = false;
+            } else {
+                sb.append(hexEncode(c));
+                atBeginning = false;
             }
         }
+        return sb.toString();
+    }
+
+    private static String hexEncode(char c) {
+        String hexString = Integer.toHexString(c).toUpperCase(Locale.ENGLISH);
+        while (hexString.length() < 4) {
+            hexString = '0' + hexString;
+        }
+        return "\\u" + hexString;
     }
 
     /**
@@ -129,6 +173,7 @@ public void createPomProperties(
 
     // CHECKSTYLE_OFF: ParameterNumber
     public void createPomProperties(
+            // TODO the session isn't needed here
             Session session,
             String groupId,
             String artifactId,

src/test/java/org/apache/maven/shared/archiver/PomPropertiesUtilTest.java

@@ -0,0 +1,126 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+package org.apache.maven.shared.archiver;
+
+import java.io.IOException;
+import java.io.Writer;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.List;
+import java.util.Properties;
+
+import org.apache.maven.api.Session;
+import org.codehaus.plexus.archiver.jar.JarArchiver;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+class PomPropertiesUtilTest {
+
+    private PomPropertiesUtil util = new PomPropertiesUtil();
+
+    @TempDir
+    Path tempDirectory;
+
+    @Test
+    void testCreatePomProperties() throws IOException {
+        Path pomPropertiesFile = tempDirectory.resolve("bar.properties");
+        util.createPomProperties(
+                (Session) null, "org.foo", "bar", "2.1.5", new JarArchiver(), null, pomPropertiesFile, true);
+
+        assertThat(pomPropertiesFile).exists();
+        Properties actual = new Properties();
+        actual.load(Files.newInputStream(pomPropertiesFile));
+        assertEquals("org.foo", actual.getProperty("groupId"));
+        assertEquals("bar", actual.getProperty("artifactId"));
+        assertEquals("2.1.5", actual.getProperty("version"));
+
+        // Now read the file directly to check for alphabetical order
+        List<String> contents = Files.readAllLines(pomPropertiesFile, StandardCharsets.ISO_8859_1);
+        assertEquals("artifactId=bar", contents.get(0));
+        assertEquals("groupId=org.foo", contents.get(1));
+        assertEquals("version=2.1.5", contents.get(2));
+        assertEquals(3, contents.size());
+    }
+
+    @Test
+    void testUnicodeEscape() throws IOException {
+        Path pomPropertiesFile = tempDirectory.resolve("bar.properties");
+        util.createPomProperties(
+                (Session) null, "org.foo", "こんにちは", "2.1.5", new JarArchiver(), null, pomPropertiesFile, true);
+
+        assertThat(pomPropertiesFile).exists();
+        Properties actual = new Properties();
+        actual.load(Files.newInputStream(pomPropertiesFile));
+        assertEquals("org.foo", actual.getProperty("groupId"));
+        assertEquals("こんにちは", actual.getProperty("artifactId"));
+        assertEquals("2.1.5", actual.getProperty("version"));
+
+        // Now read the file directly to check for alphabetical order and encoding
+        List<String> contents = Files.readAllLines(pomPropertiesFile, StandardCharsets.ISO_8859_1);
+        assertEquals("artifactId=\\u3053\\u3093\\u306B\\u3061\\u306F", contents.get(0));
+        assertEquals("groupId=org.foo", contents.get(1));
+        assertEquals("version=2.1.5", contents.get(2));
+        assertEquals(3, contents.size());
+    }
+
+    @Test
+    void testWhitespaceEscape() throws IOException {
+        Path pomPropertiesFile = tempDirectory.resolve("bar.properties");
+        Path customPomPropertiesFile = tempDirectory.resolve("custom.properties");
+        try (Writer out = Files.newBufferedWriter(customPomPropertiesFile, StandardCharsets.ISO_8859_1)) {
+            out.write("a\\u0020key\\u0020with\\u0009whitespace=value\\u0020with\\u0009whitespace\n");
+            out.write("zkey=value with \\\\ not at end of line\n");
+            out.write("ykey=\\tvalue with whitespace at beginning\n");
+            out.write("xkey=\\u00E9\\u00FC\\u00E5\n");
+        }
+
+        util.createPomProperties(
+                (Session) null,
+                "org.foo",
+                "こんにちは",
+                "2.1.5",
+                new JarArchiver(),
+                customPomPropertiesFile,
+                pomPropertiesFile,
+                true);
+        assertThat(pomPropertiesFile).exists();
+
+        Properties actual = new Properties();
+        actual.load(Files.newInputStream(pomPropertiesFile));
+        assertEquals("value with\twhitespace", actual.getProperty("a key with\twhitespace"));
+        assertEquals("value with \\ not at end of line", actual.getProperty("zkey"));
+        assertEquals("\tvalue with whitespace at beginning", actual.getProperty("ykey"));
+        assertEquals("éüå", actual.getProperty("xkey"));
+
+        // Now read the file directly to check for alphabetical order and encoding
+        List<String> contents = Files.readAllLines(pomPropertiesFile, StandardCharsets.ISO_8859_1);
+        assertEquals(7, contents.size());
+        assertEquals("a\\ key\\ with\\\twhitespace=value with\twhitespace", contents.get(0));
+        assertEquals("artifactId=\\u3053\\u3093\\u306B\\u3061\\u306F", contents.get(1));
+        assertEquals("groupId=org.foo", contents.get(2));
+        assertEquals("version=2.1.5", contents.get(3));
+        assertEquals("xkey=\\u00E9\\u00FC\\u00E5", contents.get(4));
+        assertEquals("ykey=\\\tvalue with whitespace at beginning", contents.get(5));
+        assertEquals("zkey=value with \\\\ not at end of line", contents.get(6));
+    }
+}