Fix some problems with global and upvar

Redefining a link with upvar or global gave an error.
Trying to access a non-existent var via a link gave
the wrong error message.

Added Tcl upvar tests

Signed-off-by: Steve Bennett <steveb@workware.net.au>

2 files changed, 348 insertions, 13 deletions

diff --git a/jim.c b/jim.c
index a75a2f1..defaf54 100644
--- a/jim.c
+++ b/jim.c
@@ -3765,11 +3765,24 @@ int Jim_SetVariableLink(Jim_Interp *interp, Jim_Obj *nameObjPtr,
 
     varName = Jim_GetString(nameObjPtr, &len);
 
-    if (Jim_FindHashEntry(&interp->framePtr->vars, varName)) {
-        Jim_SetResultFormatted(interp, "variable \"%#s\" already exists", nameObjPtr);
+    if (Jim_NameIsDictSugar(varName, len)) {
+        Jim_SetResultString(interp, "Dict key syntax invalid as link source", -1);
         return JIM_ERR;
     }
 
+    /* Check for an existing variable or link */
+    if (SetVariableFromAny(interp, nameObjPtr) == JIM_OK) {
+        Jim_Var *varPtr = nameObjPtr->internalRep.varValue.varPtr;
+
+        if (varPtr->linkFramePtr == NULL) {
+            Jim_SetResultFormatted(interp, "variable \"%#s\" already exists", nameObjPtr);
+            return JIM_ERR;
+        }
+
+        /* It exists, but is a link, so delete the link */
+        varPtr->linkFramePtr = NULL;
+    }
+
     /* Check for cycles. */
     if (interp->framePtr == targetCallFrame) {
         Jim_Obj *objPtr = targetNameObjPtr;
@@ -3789,10 +3802,7 @@ int Jim_SetVariableLink(Jim_Interp *interp, Jim_Obj *nameObjPtr,
             objPtr = varPtr->objPtr;
         }
     }
-    if (Jim_NameIsDictSugar(varName, len)) {
-        Jim_SetResultString(interp, "Dict key syntax invalid as link source", -1);
-        return JIM_ERR;
-    }
+
     /* Perform the binding */
     Jim_SetVariable(interp, nameObjPtr, targetNameObjPtr);
     /* We are now sure 'nameObjPtr' type is variableObjType */
@@ -3822,20 +3832,22 @@ Jim_Obj *Jim_GetVariable(Jim_Interp *interp, Jim_Obj *nameObjPtr, int flags)
                     interp->framePtr = varPtr->linkFramePtr;
                     objPtr = Jim_GetVariable(interp, varPtr->objPtr, flags);
                     interp->framePtr = savedCallFrame;
-                    return objPtr;
+                    if (objPtr) {
+                        return objPtr;
+                    }
+                    /* Error, so fall through to the error message */
                 }
             }
+            break;
 
         case JIM_DICT_SUGAR:
             /* [dict] syntax sugar. */
             return JimDictSugarGet(interp, nameObjPtr);
-
-        default:
-            if (flags & JIM_ERRMSG) {
-                Jim_SetResultFormatted(interp, "can't read \"%#s\": no such variable", nameObjPtr);
-            }
-            return NULL;
     }
+    if (flags & JIM_ERRMSG) {
+        Jim_SetResultFormatted(interp, "can't read \"%#s\": no such variable", nameObjPtr);
+    }
+    return NULL;
 }
 
 Jim_Obj *Jim_GetGlobalVariable(Jim_Interp *interp, Jim_Obj *nameObjPtr, int flags)
diff --git a/tests/upvar.test b/tests/upvar.test
new file mode 100644
index 0000000..cca8360
--- /dev/null
+++ b/tests/upvar.test
@@ -0,0 +1,323 @@
+# Commands covered:  upvar
+#
+# This file contains a collection of tests for one or more of the Tcl
+# built-in commands.  Sourcing this file into Tcl runs the tests and
+# generates output for errors.  No output means no errors were found.
+#
+# Copyright (c) 1991-1993 The Regents of the University of California.
+# Copyright (c) 1994 Sun Microsystems, Inc.
+# Copyright (c) 1998-1999 by Scriptics Corporation.
+#
+# See the file "license.terms" for information on usage and redistribution
+# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
+#
+# RCS: @(#) $Id: upvar.test,v 1.7 2000/04/10 17:19:05 ericm Exp $
+
+source testing.tcl
+
+test upvar-1.1 {reading variables with upvar} {
+    proc p1 {a b} {set c 22; set d 33; p2}
+    proc p2 {} {upvar a x1 b x2 c x3 d x4; set a abc; list $x1 $x2 $x3 $x4 $a}
+    p1 foo bar
+} {foo bar 22 33 abc}
+test upvar-1.2 {reading variables with upvar} {
+    proc p1 {a b} {set c 22; set d 33; p2}
+    proc p2 {} {p3}
+    proc p3 {} {upvar 2 a x1 b x2 c x3 d x4; set a abc; list $x1 $x2 $x3 $x4 $a}
+    p1 foo bar
+} {foo bar 22 33 abc}
+test upvar-1.3 {reading variables with upvar} {
+    proc p1 {a b} {set c 22; set d 33; p2}
+    proc p2 {} {p3}
+    proc p3 {} {
+	upvar #1 a x1 b x2 c x3 d x4
+	set a abc
+	list $x1 $x2 $x3 $x4 $a
+    }
+    p1 foo bar
+} {foo bar 22 33 abc}
+test upvar-1.4 {reading variables with upvar} {
+    set x1 44
+    set x2 55
+    proc p1 {} {p2}
+    proc p2 {} {
+	upvar 2 x1 x1 x2 a
+	upvar #0 x1 b
+	set c $b
+	incr b 3
+	list $x1 $a $b
+    }
+    p1
+} {47 55 47}
+test upvar-1.5 {reading array elements with upvar} {
+    proc p1 {} {set a(0) zeroth; set a(1) first; p2}
+    proc p2 {} {upvar a(0) x; set x}
+    p1
+} {zeroth}
+
+test upvar-2.1 {writing variables with upvar} {
+    proc p1 {a b} {set c 22; set d 33; p2; list $a $b $c $d}
+    proc p2 {} {
+	upvar a x1 b x2 c x3 d x4
+	set x1 14
+	set x4 88
+    }
+    p1 foo bar
+} {14 bar 22 88}
+test upvar-2.2 {writing variables with upvar} {
+    set x1 44
+    set x2 55
+    proc p1 {x1 x2} {
+	upvar #0 x1 a
+	upvar x2 b
+	set a $x1
+	set b $x2
+    }
+    p1 newbits morebits
+    list $x1 $x2
+} {newbits morebits}
+test upvar-2.3 {writing variables with upvar} {
+    catch {unset x1}
+    catch {unset x2}
+    proc p1 {x1 x2} {
+	upvar #0 x1 a
+	upvar x2 b
+	set a $x1
+	set b $x2
+    }
+    p1 newbits morebits
+    list [catch {set x1} msg] $msg [catch {set x2} msg] $msg
+} {0 newbits 0 morebits}
+test upvar-2.4 {writing array elements with upvar} {
+    proc p1 {} {set a(0) zeroth; set a(1) first; list [p2] $a(0)}
+    proc p2 {} {upvar a(0) x; set x xyzzy}
+    p1
+} {xyzzy xyzzy}
+
+test upvar-3.1 {unsetting variables with upvar} {
+    proc p1 {a b} {set c 22; set d 33; p2; lsort [info vars]}
+    proc p2 {} {
+	upvar 1 a x1 d x2
+	unset x1 x2
+    }
+    p1 foo bar
+} {b c}
+test upvar-3.2 {unsetting variables with upvar} {
+    proc p1 {a b} {set c 22; set d 33; p2; lsort [info vars]}
+    proc p2 {} {
+	upvar 1 a x1 d x2
+	unset x1 x2
+	set x2 28
+    }
+    p1 foo bar
+} {b c d}
+test upvar-3.3 {unsetting variables with upvar} {
+    set x1 44
+    set x2 55
+    proc p1 {} {p2}
+    proc p2 {} {
+	upvar 2 x1 a
+	upvar #0 x2 b
+	unset a b
+    }
+    p1
+    list [info exists x1] [info exists x2]
+} {0 0}
+test upvar-3.4 {unsetting variables with upvar} {
+    set x1 44
+    set x2 55
+    proc p1 {} {
+	upvar x1 a x2 b
+	unset a b
+	set b 118
+    }
+    p1
+    list [info exists x1] [catch {set x2} msg] $msg
+} {0 0 118}
+test upvar-3.5 {unsetting array elements with upvar} {
+    proc p1 {} {
+	set a(0) zeroth
+	set a(1) first
+	set a(2) second
+	p2
+	array names a
+    }
+    proc p2 {} {upvar a(0) x; unset x}
+    p1
+} {1 2}
+test upvar-3.6 {unsetting then resetting array elements with upvar} {
+    proc p1 {} {
+	set a(0) zeroth
+	set a(1) first
+	set a(2) second
+	p2
+	list [array names a] [catch {set a(0)} msg] $msg
+    }
+    proc p2 {} {upvar a(0) x; unset x; set x 12345}
+    p1
+} {{0 1 2} 0 12345}
+
+test upvar-4.1 {nested upvars} {
+    set x1 88
+    proc p1 {a b} {set c 22; set d 33; p2}
+    proc p2 {} {global x1; upvar c x2; p3}
+    proc p3 {} {
+	upvar x1 a x2 b
+	list $a $b
+    }
+    p1 14 15
+} {88 22}
+test upvar-4.2 {nested upvars} {
+    set x1 88
+    proc p1 {a b} {set c 22; set d 33; p2; list $a $b $c $d}
+    proc p2 {} {global x1; upvar c x2; p3}
+    proc p3 {} {
+	upvar x1 a x2 b
+	set a foo
+	set b bar
+    }
+    list [p1 14 15] $x1
+} {{14 15 bar 33} foo}
+
+proc tproc {args} {global x; set x [list $args [uplevel info vars]]}
+
+test upvar-6.1 {retargeting an upvar} {
+    proc p1 {} {
+	set a(0) zeroth
+	set a(1) first
+	set a(2) second
+	p2
+    }
+    proc p2 {} {
+	upvar a x
+	set result {}
+	foreach i [array names x] {
+	    upvar a($i) x
+	    lappend result $x
+	}
+	lsort $result
+    }
+    p1
+} {first second zeroth}
+test upvar-6.2 {retargeting an upvar} {
+    set x 44
+    set y abcde
+    proc p1 {} {
+	global x
+	set result $x
+	upvar y x
+	lappend result $x
+    }
+    p1
+} {44 abcde}
+test upvar-6.3 {retargeting an upvar} {
+    set x 44
+    set y abcde
+    proc p1 {} {
+	upvar y x
+	lappend result $x
+	global x
+	lappend result $x
+    }
+    p1
+} {abcde 44}
+
+test upvar-7.1 {upvar to same level} {
+    set x 44
+    set y 55
+    catch {unset uv}
+    upvar #0 x uv
+    set uv abc
+    upvar 0 y uv
+    set uv xyzzy
+    list $x $y
+} {abc xyzzy}
+test upvar-7.2 {upvar to same level} {
+    set x 1234
+    set y 4567
+    proc p1 {x y} {
+	upvar 0 x uv
+	set uv $y
+	return "$x $y"
+    }
+    p1 44 89
+} {89 89}
+test upvar-7.3 {upvar to same level} {
+    set x 1234
+    set y 4567
+    proc p1 {x y} {
+	upvar #1 x uv
+	set uv $y
+	return "$x $y"
+    }
+    p1 xyz abc
+} {abc abc}
+test upvar-7.4 {upvar to same level: tricky problems when deleting variable table} {
+    proc tt {} {upvar #1 toto loc;  return $loc}
+    list [catch tt msg] $msg
+} {1 {can't read "loc": no such variable}}
+test upvar-7.5 {potential memory leak when deleting variable table} {
+    proc leak {} {
+	array set foo {1 2 3 4}
+	upvar 0 foo(1) bar
+    }
+    leak
+} {}
+
+test upvar-8.1 {errors in upvar command} {
+    catch upvar msg
+} 1
+test upvar-8.2 {errors in upvar command} {
+    catch {upvar 1}
+} 1
+test upvar-8.3 {errors in upvar command} {
+    proc p1 {} {upvar a b c}
+    catch p1
+} 1
+test upvar-8.4 {errors in upvar command} {
+    proc p1 {} {upvar 0 b b}
+    list [catch p1 msg] $msg
+} {1 {can't upvar from variable to itself}}
+test upvar-8.5 {errors in upvar command} {
+    proc p1 {} {upvar 0 a b; upvar 0 b a}
+    list [catch p1 msg] $msg
+} {1 {can't upvar from variable to itself}}
+test upvar-8.6 {errors in upvar command} {
+    proc p1 {} {set a 33; upvar b a}
+    list [catch p1 msg] $msg
+} {1 {variable "a" already exists}}
+# Jim allows dicts within dicts. Tcl can't do this.
+test upvar-8.8 {create nested array with upvar} {
+    proc p1 {} {upvar x(a) b; set b(2) 44}
+    catch {unset x}
+    p1
+    set x
+} {a {2 44}}
+test upvar-8.10 {upvar will create element alias for new array element} {
+    catch {unset upvarArray}
+    array set upvarArray {}
+    catch {upvar 0 upvarArray(elem) upvarArrayElemAlias}
+} {0}
+test upvar-9.1 {global redefine} {
+    proc p1 {} { global x; global x }
+    p1
+} {}
+test upvar-9.2 {upvar redefine} {
+    set a 1
+    set b 2
+    proc p1 {} { upvar a x; upvar b x; return $x }
+    p1
+} 2
+test upvar-9.3 {upvar redefine static} {
+    proc p1 {} {{a 3}} { upvar b a; return $b }
+    list [catch p1 msg] $msg
+} {1 {variable "a" already exists}}
+test upvar-9.4 {upvar links to static} {
+    proc p1 {} {} { upvar a x; incr x; return $x }
+    proc p2 {} {{a 3}} { list [p1] $a }
+    p2
+} {4 4}
+
+catch {unset a}
+
+testreport