* generic/tclPathObj.c: Fixed some internals management in the "path"

        Tcl_ObjType for the empty string value.  Problem led to a crash in
        the command [glob -dir {} a]. [Bug 1999176].

2 files changed, 31 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index f90c797..6b9dbbc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2008-06-24  Don Porter  <dgp@users.sourceforge.net>
+
+	* generic/tclPathObj.c:	Fixed some internals management in the "path"
+	Tcl_ObjType for the empty string value.  Problem led to a crash in
+	the command [glob -dir {} a]. [Bug 1999176].
+
 2008-06-24  Pat Thoyts  <patthoyts@users.sourceforge.net>
 
 	* doc/fileevent.n: bug #1995063 fix examples and comment on eof use.
diff --git a/generic/tclPathObj.c b/generic/tclPathObj.c
index f292c8a..c41aafc 100644
--- a/generic/tclPathObj.c
+++ b/generic/tclPathObj.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: tclPathObj.c,v 1.69 2008/06/23 15:34:15 dgp Exp $
+ * RCS: @(#) $Id: tclPathObj.c,v 1.70 2008/06/24 20:02:31 dgp Exp $
  */
 
 #include "tclInt.h"
@@ -1768,6 +1768,16 @@ Tcl_FSGetNormalizedPath(
 
 	if (pathType == TCL_PATH_RELATIVE) {
 	    Tcl_Obj *origDir = fsPathPtr->cwdPtr;
+
+	    /*
+	     * NOTE: here we are (dangerously?) assuming that origDir points
+	     * to a Tcl_Obj with Tcl_ObjType == &tclFsPathType .  The
+	     *     pathType = Tcl_FSGetPathType(fsPathPtr->cwdPtr);
+	     * above that set the pathType value should have established
+	     * that, but it's far less clear on what basis we know there's
+	     * been no shimmering since then.
+	     */
+
 	    FsPath *origDirFsPathPtr = PATHOBJ(origDir);
 
 	    fsPathPtr->cwdPtr = origDirFsPathPtr->cwdPtr;
@@ -1881,7 +1891,20 @@ Tcl_FSGetNormalizedPath(
 	 * might loop back through here.
 	 */
 
-	if (path[0] != '\0') {
+	if (path[0] == '\0') {
+	    /*
+	     * Special handling for the empty string value.  This one is
+	     * very weird with [file normalize {}] => {}.  (The reasoning
+	     * supporting this is unknown to DGP, but he fears changing it.)
+	     * Attempt here to keep the expectations of other parts of
+	     * Tcl_Filesystem code about state of the FsPath fields satisfied.
+	     *
+	     * In particular, capture the cwd value and save so it can be
+	     * stored in the cwdPtr field below.
+	     */
+	    useThisCwd = Tcl_FSGetCwd(interp);
+
+	} else {
 	    /*
 	     * We don't ask for the type of 'pathPtr' here, because that is
 	     * not correct for our purposes when we have a path like '~'. Tcl