Fix false difference detected with CachingOutputStream/CachingWriter when streams are flushed (#252)

gnodet · web-flow · commit 3bd741ddc1cc · 2023-05-22T11:40:23.000+02:00
diff --git a/src/main/java/org/codehaus/plexus/util/io/CachingOutputStream.java b/src/main/java/org/codehaus/plexus/util/io/CachingOutputStream.java
@@ -123,6 +123,7 @@ private void flushBuffer( ByteBuffer writeBuffer ) throws IOException
             {
                 readBuffer = this.readBuffer;
                 ( ( Buffer ) readBuffer ).clear();
+                readBuffer.limit( len );
             }
             else
             {
diff --git a/src/test/java/org/codehaus/plexus/util/io/CachingWriterTest.java b/src/test/java/org/codehaus/plexus/util/io/CachingWriterTest.java
@@ -17,6 +17,7 @@
  */
 
 import java.io.IOException;
+import java.io.Writer;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Files;
 import java.nio.file.Path;
@@ -63,6 +64,32 @@ private void waitLastModified() throws IOException, InterruptedException
         }
     }
 
+    @Test
+    public void testNoOverwriteWithFlush() throws IOException, InterruptedException
+    {
+        String data = "Hello world!";
+        Path path = tempDir.resolve("file-bigger.txt");
+        assertFalse( Files.exists(path));
+
+        try (Writer w = Files.newBufferedWriter(path, StandardCharsets.UTF_8)) {
+            for (int i = 0; i < 10; i++) {
+                w.write(data);
+            }
+        }
+        FileTime modified = Files.getLastModifiedTime(path);
+
+        waitLastModified();
+
+        try (Writer w = new CachingWriter(path, StandardCharsets.UTF_8)) {
+            for (int i = 0; i < 10; i++) {
+                w.write(data);
+                w.flush();
+            }
+        }
+        FileTime newModified = Files.getLastModifiedTime(path);
+        assertEquals(modified, newModified);
+    }
+
     @Test
     public void testWriteNoExistingFile() throws IOException, InterruptedException
     {

Original file line number	Diff line number	Diff line change
`@@ -123,6 +123,7 @@ private void flushBuffer( ByteBuffer writeBuffer ) throws IOException`
`123`	`123`	`{`
`124`	`124`	`readBuffer = this.readBuffer;`
`125`	`125`	`( ( Buffer ) readBuffer ).clear();`
	`126`	`+ readBuffer.limit( len );`
`126`	`127`	`}`
`127`	`128`	`else`
`128`	`129`	`{`