* generic/tclIO.c (CopyData): [Bug 2895565]. Dropped bogosity

	* tests/io.test: which used the number of _written_ bytes or
	character to update the counters for the read bytes/characters.
	New test io-53.11. This is a forward port from the 8.5 branch.

1 files changed, 12 insertions, 9 deletions

diff --git a/generic/tclIO.c b/generic/tclIO.c
index e295c82..e8d231a 100644
--- a/generic/tclIO.c
+++ b/generic/tclIO.c
@@ -10,7 +10,7 @@
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclIO.c,v 1.166 2009/11/10 23:50:17 ferrieux Exp $
+ * RCS: @(#) $Id: tclIO.c,v 1.167 2009/11/12 17:25:18 andreas_kupries Exp $
  */
 
 #include "tclInt.h"
@@ -9092,14 +9092,17 @@ CopyData(
 	    sizeb = DoWriteChars(outStatePtr->topChanPtr, buffer, sizeb);
 	}
 
-	if (inBinary || sameEncoding) {
-	    /*
-	     * Both read and write counted bytes.
-	     */
-
-	    size = sizeb;
-	} /* else: Read counted characters, write counted bytes, i.e.
-	   * size != sizeb */
+	/*
+	 * [Bug 2895565]. At this point 'size' still contains the number of
+	 * bytes or characters which have been read. We keep this to later to
+	 * update the totals and toRead information, see marker (UP) below. We
+	 * must not overwrite it with 'sizeb', which is the number of written
+	 * bytes or characters, and both EOL translation and encoding
+	 * conversion may have changed this number unpredictably in relation
+	 * to 'size' (It can be smaller or larger, in the latter case able to
+	 * drive toRead below -1, causing infinite looping). Completely
+	 * unsuitable for updating totals and toRead.
+	 */
 
 	if (sizeb < 0) {
 	writeError: