* generic/tclIndexObj.c (Tcl_GetIndexFromObjStruct): It seems

        * tests/indexObj.test:  there are extensions that rely on the prior
        * doc/GetIndex.3:        behavior that the empty string cannot succeed
        as a unique prefix matcher, so I'm restoring Donal Fellow's solution.
        Added mention of this detail to the documentation.  [Bug 1464039]

4 files changed, 17 insertions, 7 deletions

diff --git a/ChangeLog b/ChangeLog
index fcbfb64..d2dcd34 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2006-04-06  Don Porter  <dgp@users.sourceforge.net>
 
+        * generic/tclIndexObj.c (Tcl_GetIndexFromObjStruct):    It seems
+        * tests/indexObj.test:  there are extensions that rely on the prior
+        * doc/GetIndex.3:        behavior that the empty string cannot succeed
+        as a unique prefix matcher, so I'm restoring Donal Fellow's solution.
+        Added mention of this detail to the documentation.  [Bug 1464039]
+
 	* tests/compExpr-old.test:	Updated testmathfunctions constraint
 	* tests/compExpr.test:		to post-TIP-232 world.
 	* tests/expr-old.test:
diff --git a/doc/GetIndex.3 b/doc/GetIndex.3
index f476ea5..4b4a220 100644
--- a/doc/GetIndex.3
+++ b/doc/GetIndex.3
@@ -4,7 +4,7 @@
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 '\" 
-'\" RCS: @(#) $Id: GetIndex.3,v 1.18 2005/05/10 18:33:56 kennykb Exp $
+'\" RCS: @(#) $Id: GetIndex.3,v 1.19 2006/04/06 18:57:58 dgp Exp $
 '\" 
 .so man.macros
 .TH Tcl_GetIndexFromObj 3 8.1 Tcl "Tcl Library Procedures"
@@ -60,7 +60,7 @@ an object must be one of a predefined set of values.
 \fIObjPtr\fR is compared against each of
 the strings in \fItablePtr\fR to find a match.  A match occurs if
 \fIobjPtr\fR's string value is identical to one of the strings in
-\fItablePtr\fR, or if it is a unique abbreviation
+\fItablePtr\fR, or if it is a non-empty unique abbreviation
 for exactly one of the strings in \fItablePtr\fR and the
 \fBTCL_EXACT\fR flag was not specified; in either case
 the index of the matching entry is stored at \fI*indexPtr\fR
diff --git a/generic/tclIndexObj.c b/generic/tclIndexObj.c
index be60517..df658dd 100644
--- a/generic/tclIndexObj.c
+++ b/generic/tclIndexObj.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: tclIndexObj.c,v 1.30 2006/04/05 15:17:39 dgp Exp $
+ * RCS: @(#) $Id: tclIndexObj.c,v 1.31 2006/04/06 18:57:58 dgp Exp $
  */
 
 #include "tclInt.h"
@@ -226,7 +226,7 @@ Tcl_GetIndexFromObjStruct(
      * Check if we were instructed to disallow abbreviations.
      */
 
-    if ((flags & TCL_EXACT) || (numAbbrev != 1)) {
+    if ((flags & TCL_EXACT) || (key[0] == '\0') || (numAbbrev != 1)) {
 	goto error;
     }
 
diff --git a/tests/indexObj.test b/tests/indexObj.test
index bb1c0a4..4c1ef49 100644
--- a/tests/indexObj.test
+++ b/tests/indexObj.test
@@ -8,7 +8,7 @@
 # See the file "license.terms" for information on usage and redistribution
 # of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 #
-# RCS: @(#) $Id: indexObj.test,v 1.14 2006/04/06 18:19:25 dgp Exp $
+# RCS: @(#) $Id: indexObj.test,v 1.15 2006/04/06 18:57:58 dgp Exp $
 
 if {[lsearch [namespace children] ::tcltest] == -1} {
     package require tcltest
@@ -70,8 +70,12 @@ test indexObj-2.8 {exact match of empty values: singleton case} testindexobj {
     list [catch {testindexobj 1 0 {} a} msg] $msg
 } {1 {bad token "": must be a}}
 test indexObj-2.9 {non-exact match of empty values: singleton case} testindexobj {
-    testindexobj 1 1 {} a
-} 0
+    # NOTE this is a special case.  Although the empty string is a
+    # unique prefix, we have an established history of rejecting
+    # empty lookup keys, requiring any unique prefix match to have
+    # at least one character.
+    list [catch {testindexobj 1 1 {} a} msg] $msg
+} {1 {bad token "": must be a}}
 
 test indexObj-3.1 {cache result to skip next lookup} testindexobj {
     testindexobj check 42