* generic/tclCompile.c (TclCompileScript):

	* generic/tclLiteral.c (TclReleaseLiteral): fix for [Bug 467523],
	which resurfaced with the latest changes. The previous strategy
	was to have special code in TclReleaseLiteral to handle the
	self-references generated by empty scripts. The new approach
	avoids the self-reference altogether, by having empty scripts
	return an unshared literal.

2 files changed, 9 insertions, 20 deletions

diff --git a/generic/tclCompile.c b/generic/tclCompile.c
index 5376123..03b62ca 100644
--- a/generic/tclCompile.c
+++ b/generic/tclCompile.c
@@ -11,7 +11,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclCompile.c,v 1.70 2004/07/08 18:46:05 msofer Exp $
+ * RCS: @(#) $Id: tclCompile.c,v 1.71 2004/07/15 17:42:12 msofer Exp $
  */
 
 #include "tclInt.h"
@@ -1208,11 +1208,16 @@ TclCompileScript(interp, script, numBytes, envPtr)
     /*
      * If the source script yielded no instructions (e.g., if it was empty),
      * push an empty string as the command's result.
+     *
+     * WARNING: push an unshared object! If the script being compiled is a
+     * shared empty string, it will otherwise be self-referential and cause
+     * difficulties with literal management [Bugs 467523, 983660]. We used to
+     * have special code in TclReleaseLiteral to handle this particular
+     * self-reference, but now opt for avoiding its creation altogether.
      */
     
     if (envPtr->codeNext == entryCodeNext) {
-	TclEmitPush(TclRegisterLiteral(envPtr, "", 0, /*onHeap*/ 0),
-	        envPtr);
+	TclEmitPush(TclAddLiteralObj(envPtr, Tcl_NewObj(), NULL), envPtr);
     }
     
     envPtr->numSrcBytes = (p - script);
diff --git a/generic/tclLiteral.c b/generic/tclLiteral.c
index 19042fd..ad38167 100644
--- a/generic/tclLiteral.c
+++ b/generic/tclLiteral.c
@@ -12,7 +12,7 @@
  * See the file "license.terms" for information on usage and redistribution
  * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclLiteral.c,v 1.16 2004/07/08 18:46:06 msofer Exp $
+ * RCS: @(#) $Id: tclLiteral.c,v 1.17 2004/07/15 17:42:12 msofer Exp $
  */
 
 #include "tclInt.h"
@@ -731,22 +731,6 @@ TclReleaseLiteral(interp, objPtr)
     }
 
     /*
-     * Check if the LiteralEntry is only being kept alive by 
-     * a circular reference from a ByteCode stored as its 
-     * internal rep. In that case, set the ByteCode object array 
-     * entry NULL to signal to TclCleanupByteCode to not try to 
-     * release this about to be freed literal again.
-     */
-    
-    if (objPtr->typePtr == &tclByteCodeType) {
-	codePtr = (ByteCode *) objPtr->internalRep.otherValuePtr;
-	if ((codePtr->numLitObjects == 1)
-		&& (codePtr->objArrayPtr[0] == objPtr)) {			
-	    codePtr->objArrayPtr[0] = NULL;
-	}
-    }
-    
-    /*
      * Remove the reference corresponding to the local literal table
      * entry.
      */