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authorandreas_kupries <akupries@shaw.ca>2009-12-10 19:13:26 (GMT)
committerandreas_kupries <akupries@shaw.ca>2009-12-10 19:13:26 (GMT)
commita70b4959890f4ab6855ae91437fd9b7cfe3c668e (patch)
treec2c7910bdf357aece499064863798acd8fd383d2
parent0f8faf662b1416020d07306938d282ee1f6eee1b (diff)
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* generic/tclObj.c (TclContinuationsEnter): [Bug 2895323]: Updated
comments to describe when the function can be entered for the same Tcl_Obj* multiple times. This is a continuation of the 2009-11-10 entry where a memory leak was plugged, but where not sure if that was just a band-aid to paper over some other error. It isn't, this is a legal situation.
-rw-r--r--ChangeLog9
-rw-r--r--generic/tclObj.c24
2 files changed, 28 insertions, 5 deletions
diff --git a/ChangeLog b/ChangeLog
index 894fbd4..2c1bd26 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+2009-12-10 Andreas Kupries <andreask@activestate.com>
+
+ * generic/tclObj.c (TclContinuationsEnter): [Bug 2895323]: Updated
+ comments to describe when the function can be entered for the same
+ Tcl_Obj* multiple times. This is a continuation of the 2009-11-10
+ entry where a memory leak was plugged, but where not sure if that
+ was just a band-aid to paper over some other error. It isn't, this
+ is a legal situation.
+
2009-12-10 Miguel Sofer <msofer@users.sf.net>
* generic/tclBasic.c: Reducing the # of moving parts for
diff --git a/generic/tclObj.c b/generic/tclObj.c
index 5913dd1..667fd90 100644
--- a/generic/tclObj.c
+++ b/generic/tclObj.c
@@ -13,7 +13,7 @@
* See the file "license.terms" for information on usage and redistribution of
* this file, and for a DISCLAIMER OF ALL WARRANTIES.
*
- * RCS: @(#) $Id: tclObj.c,v 1.164 2009/11/10 17:57:39 andreas_kupries Exp $
+ * RCS: @(#) $Id: tclObj.c,v 1.165 2009/12/10 19:13:26 andreas_kupries Exp $
*/
#include "tclInt.h"
@@ -584,10 +584,24 @@ TclContinuationsEnter(Tcl_Obj* objPtr,
if (!newEntry) {
/*
- * Somehow we're entering ContLineLoc data for the same value (objPtr)
- * more than one time. Not sure whether that's expected, or a sign of
- * trouble, but at a minimum, we should take care not to leak the old
- * entry.
+ * We're entering ContLineLoc data for the same value more than one
+ * time. Taking care not to leak the old entry.
+ *
+ * This can happen when literals in a proc body are shared. See for
+ * example test info-30.19 where the action (code) for all branches of
+ * the switch command is identical, mapping them all to the same
+ * literal. An interesting result of this is that the number and
+ * locations (offset) of invisible continuation lines in the literal
+ * are the same for all occurences.
+ *
+ * Note that while reusing the existing entry is possible it requires
+ * the same actions as for a new entry because we have to copy the
+ * incoming num/loc data even so. Because we are called from
+ * TclContinuationsEnterDerived for this case, which modified the
+ * stored locations (Rebased to the proper relative offset). Just
+ * returning the stored entry would rebase them a second time, or
+ * more, hosing the data. It is easier to simply replace, as we are
+ * doing.
*/
ckfree((char *) Tcl_GetHashValue(hPtr));