* generic/tclEvent.c ([::tcl::Bgerror]): Corrections to Tcl's

        * tests/event.test:     default [interp bgerror] handler so that when
        it falls back to a hidden [bgerror] in a safe interp, it gets the
        right error context data.  [Bug 1790274].

3 files changed, 74 insertions, 14 deletions

diff --git a/ChangeLog b/ChangeLog
index cbf9737..04b7dda 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2007-09-07  Don Porter  <dgp@users.sourceforge.net>
+
+	* generic/tclEvent.c ([::tcl::Bgerror]):	Corrections to Tcl's
+	* tests/event.test:	default [interp bgerror] handler so that when
+	it falls back to a hidden [bgerror] in a safe interp, it gets the
+	right error context data.  [Bug 1790274].
+
 2007-09-07  Miguel Sofer  <msofer@users.sf.net>
 
 	* generic/tclProc.c (TclInitCompiledLocals): the refCount of
diff --git a/generic/tclEvent.c b/generic/tclEvent.c
index 78b44c2..e9619bc 100644
--- a/generic/tclEvent.c
+++ b/generic/tclEvent.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: tclEvent.c,v 1.75 2007/09/07 15:51:25 dgp Exp $
+ * RCS: @(#) $Id: tclEvent.c,v 1.76 2007/09/07 18:11:24 dgp Exp $
  */
 
 #include "tclInt.h"
@@ -310,6 +310,7 @@ TclDefaultBgErrorHandlerObjCmd(
     Tcl_Obj *keyPtr, *valuePtr;
     Tcl_Obj *tempObjv[2];
     int code, level;
+    Tcl_InterpState saved;
 
     if (objc != 3) {
 	Tcl_WrongNumArgs(interp, 1, objv, "msg options");
@@ -358,6 +359,10 @@ TclDefaultBgErrorHandlerObjCmd(
     }
     Tcl_IncrRefCount(tempObjv[1]);
 
+    if (code != TCL_ERROR) {
+	Tcl_SetObjResult(interp, tempObjv[1]);
+    }
+
     TclNewLiteralStringObj(keyPtr, "-errorcode");
     Tcl_IncrRefCount(keyPtr);
     Tcl_DictObjGet(NULL, objv[2], keyPtr, &valuePtr);
@@ -371,17 +376,21 @@ TclDefaultBgErrorHandlerObjCmd(
     Tcl_DictObjGet(NULL, objv[2], keyPtr, &valuePtr);
     Tcl_DecrRefCount(keyPtr);
     if (valuePtr) {
-	if (code != TCL_ERROR) {
-	    Tcl_SetObjResult(interp, tempObjv[1]);
-	}
 	Tcl_IncrRefCount(valuePtr);
 	Tcl_AppendObjToErrorInfo(interp, valuePtr);
     }
 
-    /* Capture stack trace now, so we can report it if [bgerror] fails. */
-    valuePtr = Tcl_GetVar2Ex(interp, "errorInfo", NULL, TCL_GLOBAL_ONLY);
-    Tcl_IncrRefCount(valuePtr);
+    if (code == TCL_ERROR) {
+	Tcl_SetObjResult(interp, tempObjv[1]);
+    }
 
+    /*
+     * Save interpreter state so we can restore it if multiple handler
+     * attempts are needed.
+     */
+
+    saved = Tcl_SaveInterpState(interp, code);
+    
     /* Invoke the bgerror command. */
     Tcl_AllowExceptions(interp);
     code = Tcl_EvalObjv(interp, 2, tempObjv, TCL_EVAL_GLOBAL);
@@ -397,7 +406,7 @@ TclDefaultBgErrorHandlerObjCmd(
 	 */
 
 	if (Tcl_IsSafe(interp)) {
-	    Tcl_ResetResult(interp);
+	    Tcl_RestoreInterpState(interp, saved);
 	    TclObjInvoke(interp, 2, tempObjv, TCL_INVOKE_HIDDEN);
 	} else {
 	    Tcl_Channel errChannel = Tcl_GetStdChannel(TCL_STDERR);
@@ -407,11 +416,12 @@ TclDefaultBgErrorHandlerObjCmd(
 		Tcl_IncrRefCount(resultPtr);
 		if (Tcl_FindCommand(interp, "bgerror", NULL,
 			TCL_GLOBAL_ONLY) == NULL) {
-		    if (valuePtr) {
-			Tcl_WriteObj(errChannel, valuePtr);
-			Tcl_WriteChars(errChannel, "\n", -1);
-		    }
+		    Tcl_RestoreInterpState(interp, saved);
+		    Tcl_WriteObj(errChannel, Tcl_GetVar2Ex(interp,
+			    "errorInfo", NULL, TCL_GLOBAL_ONLY));
+		    Tcl_WriteChars(errChannel, "\n", -1);
 		} else {
+		    Tcl_DiscardInterpState(saved);
 		    Tcl_WriteChars(errChannel,
 			    "bgerror failed to handle background error.\n",-1);
 		    Tcl_WriteChars(errChannel, "    Original error: ", -1);
@@ -423,11 +433,15 @@ TclDefaultBgErrorHandlerObjCmd(
 		}
 		Tcl_DecrRefCount(resultPtr);
 		Tcl_Flush(errChannel);
+	    } else {
+		Tcl_DiscardInterpState(saved);
 	    }
 	}
 	code = TCL_OK;
+    } else {
+	Tcl_DiscardInterpState(saved);
     }
-    Tcl_DecrRefCount(valuePtr);
+
     Tcl_DecrRefCount(tempObjv[0]);
     Tcl_DecrRefCount(tempObjv[1]);
     Tcl_ResetResult(interp);
diff --git a/tests/event.test b/tests/event.test
index 101a17e..9006131 100644
--- a/tests/event.test
+++ b/tests/event.test
@@ -9,7 +9,7 @@
 # See the file "license.terms" for information on usage and redistribution
 # of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 #
-# RCS: @(#) $Id: event.test,v 1.24 2007/03/12 19:28:50 dgp Exp $
+# RCS: @(#) $Id: event.test,v 1.25 2007/09/07 18:11:24 dgp Exp $
 
 package require tcltest 2
 namespace import -force ::tcltest::*
@@ -304,6 +304,45 @@ test event-7.5 {correct behaviour when there is no bgerror [Bug 219142]} {exec}
 "error hello"
     ("after" script)}}
 
+test event-7.6 {safe hidden bgerror fallback} {
+    variable result {}
+    interp create -safe safe
+    safe alias puts puts
+    safe alias result ::append [namespace which -variable result]
+    safe eval {proc bgerror m {result $m\n$::errorCode\n$::errorInfo\n}}
+    safe hide bgerror
+    safe eval after 0 error foo
+    update
+    interp delete safe
+    set result
+} {foo
+NONE
+foo
+    while executing
+"error foo"
+    ("after" script)
+}
+
+test event-7.7 {safe hidden bgerror fallback} {
+    variable result {}
+    interp create -safe safe
+    safe alias puts puts
+    safe alias result ::append [namespace which -variable result]
+    safe eval {proc bgerror m {result $m\n$::errorCode\n$::errorInfo\n}}
+    safe hide bgerror
+    safe eval {proc bgerror m {error bar soom baz}}
+    safe eval after 0 error foo
+    update
+    interp delete safe
+    set result
+} {foo
+NONE
+foo
+    while executing
+"error foo"
+    ("after" script)
+}
+
 
 # someday : add a test checking that 
 # when there is no bgerror, an error msg goes to stderr