Fix false difference detected with CachingOutputStream/CachingWriter …

…when streams are flushed (#252)
codehaus-plexus · May 22, 2023 · 3bd741d · 3bd741d
1 parent b4ee91f
commit 3bd741d
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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
     {