Reduce shimmering: If a conclusion can be drawn about the number of list elements, don't get the elements before the list length is checked

13 files changed, 76 insertions, 22 deletions

diff --git a/generic/tclArithSeries.h b/generic/tclArithSeries.h
index 1daacdd..28fd993 100644
--- a/generic/tclArithSeries.h
+++ b/generic/tclArithSeries.h
@@ -15,7 +15,7 @@
  * Note that the len can in theory be always computed by start,end,step
  * but it's faster to cache it inside the internal representation.
  */
-typedef struct ArithSeries {
+typedef struct {
     Tcl_Size len;
     Tcl_Obj **elements;
     int isDouble;
@@ -23,7 +23,7 @@ typedef struct ArithSeries {
     Tcl_WideInt end;
     Tcl_WideInt step;
 } ArithSeries;
-typedef struct ArithSeriesDbl {
+typedef struct {
     Tcl_Size len;
     Tcl_Obj **elements;
     int isDouble;
diff --git a/generic/tclAssembly.c b/generic/tclAssembly.c
index dbf37bb8..ab5cd7a 100644
--- a/generic/tclAssembly.c
+++ b/generic/tclAssembly.c
@@ -1985,7 +1985,7 @@ CreateMirrorJumpTable(
 				 * table. */
     int i;
 
-    if (TclListObjGetElementsM(interp, jumps, &objc, &objv) != TCL_OK) {
+    if (TclListObjLengthM(interp, jumps, &objc) != TCL_OK) {
 	return TCL_ERROR;
     }
     if (objc % 2 != 0) {
@@ -1997,6 +1997,9 @@ CreateMirrorJumpTable(
 	}
 	return TCL_ERROR;
     }
+    if (TclListObjGetElementsM(interp, jumps, &objc, &objv) != TCL_OK) {
+	return TCL_ERROR;
+    }
 
     /*
      * Allocate the jumptable.
diff --git a/generic/tclBinary.c b/generic/tclBinary.c
index e4c8766..b744203 100644
--- a/generic/tclBinary.c
+++ b/generic/tclBinary.c
@@ -1125,11 +1125,10 @@ BinaryFormatCmd(
 		 * The macro evals its args more than once: avoid arg++
 		 */
 
-		if (TclListObjGetElementsM(interp, objv[arg], &listc,
-			&listv) != TCL_OK) {
+		if (TclListObjLengthM(interp, objv[arg], &listc
+			) != TCL_OK) {
 		    return TCL_ERROR;
 		}
-		arg++;
 
 		if (count == BINARY_ALL) {
 		    count = listc;
@@ -1139,6 +1138,11 @@ BinaryFormatCmd(
 			    -1));
 		    return TCL_ERROR;
 		}
+		if (TclListObjGetElementsM(interp, objv[arg], &listc,
+			&listv) != TCL_OK) {
+		    return TCL_ERROR;
+		}
+		arg++;
 	    }
 	    offset += count*size;
 	    break;
diff --git a/generic/tclCmdAH.c b/generic/tclCmdAH.c
index 9905633..2281b5a 100644
--- a/generic/tclCmdAH.c
+++ b/generic/tclCmdAH.c
@@ -2860,8 +2860,8 @@ EachloopCmd(
 	    result = TCL_ERROR;
 	    goto done;
 	}
-	TclListObjGetElementsM(NULL, statePtr->vCopyList[i],
-	    &statePtr->varcList[i], &statePtr->varvList[i]);
+	TclListObjLengthM(NULL, statePtr->vCopyList[i],
+	    &statePtr->varcList[i]);
 	if (statePtr->varcList[i] < 1) {
 	    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
 		"%s varlist is empty",
@@ -2872,6 +2872,8 @@ EachloopCmd(
 	    result = TCL_ERROR;
 	    goto done;
 	}
+	TclListObjGetElementsM(NULL, statePtr->vCopyList[i],
+	    &statePtr->varcList[i], &statePtr->varvList[i]);
 
 	/* Values */
 	if (TclHasInternalRep(objv[2+i*2],&tclArithSeriesType)) {
diff --git a/generic/tclCmdIL.c b/generic/tclCmdIL.c
index e2493c4..8e52d65 100644
--- a/generic/tclCmdIL.c
+++ b/generic/tclCmdIL.c
@@ -20,6 +20,7 @@
 #include "tclInt.h"
 #include "tclRegexp.h"
 #include "tclArithSeries.h"
+#include "tclTomMath.h"
 #include <math.h>
 #include <assert.h>
 
@@ -2573,6 +2574,7 @@ Tcl_LlengthObjCmd(
 				/* Argument objects. */
 {
     int listLen, result;
+    Tcl_Obj *objPtr;
 
     if (objc != 2) {
 	Tcl_WrongNumArgs(interp, 1, objv, "list");
@@ -2589,7 +2591,8 @@ Tcl_LlengthObjCmd(
      * length.
      */
 
-    Tcl_SetObjResult(interp, Tcl_NewWideIntObj(listLen));
+    TclNewUIntObj(objPtr, listLen);
+    Tcl_SetObjResult(interp, objPtr);
     return TCL_OK;
 }
 
@@ -3152,7 +3155,7 @@ Tcl_LreverseObjCmd(
     } /* end ArithSeries */
 
     /* True List */
-    if (TclListObjGetElementsM(interp, objv[1], &elemc, &elemv) != TCL_OK) {
+    if (TclListObjLengthM(interp, objv[1], &elemc) != TCL_OK) {
 	return TCL_ERROR;
     }
 
@@ -3164,6 +3167,9 @@ Tcl_LreverseObjCmd(
 	Tcl_SetObjResult(interp, objv[1]);
 	return TCL_OK;
     }
+    if (TclListObjGetElementsM(interp, objv[1], &elemc, &elemv) != TCL_OK) {
+	return TCL_ERROR;
+    }
 
     if (Tcl_IsShared(objv[1])
 	|| ListObjRepIsShared(objv[1])) { /* Bug 1675044 */
diff --git a/generic/tclCmdMZ.c b/generic/tclCmdMZ.c
index 57541f9..147c2dc 100644
--- a/generic/tclCmdMZ.c
+++ b/generic/tclCmdMZ.c
@@ -3610,7 +3610,7 @@ TclNRSwitchObjCmd(
 	Tcl_Obj **listv;
 
 	blist = objv[0];
-	if (TclListObjGetElementsM(interp, objv[0], &objc, &listv) != TCL_OK) {
+	if (TclListObjLengthM(interp, objv[0], &objc) != TCL_OK) {
 	    return TCL_ERROR;
 	}
 
@@ -3623,6 +3623,9 @@ TclNRSwitchObjCmd(
 		    "?-option ...? string {?pattern body ...? ?default body?}");
 	    return TCL_ERROR;
 	}
+	if (TclListObjGetElementsM(interp, objv[0], &objc, &listv) != TCL_OK) {
+	    return TCL_ERROR;
+	}
 	objv = listv;
 	splitObjs = 1;
     }
diff --git a/generic/tclDecls.h b/generic/tclDecls.h
index 75fc17e..d8b4b5d 100644
--- a/generic/tclDecls.h
+++ b/generic/tclDecls.h
@@ -4182,6 +4182,7 @@ extern const TclStubs *tclStubsPtr;
 /* !END!: Do not edit above this line. */
 
 #undef TclUnusedStubEntry
+
 #if defined(USE_TCL_STUBS)
 #   undef Tcl_CreateInterp
 #   undef Tcl_FindExecutable
diff --git a/generic/tclEnsemble.c b/generic/tclEnsemble.c
index 88b611f..963f1d8 100644
--- a/generic/tclEnsemble.c
+++ b/generic/tclEnsemble.c
@@ -562,8 +562,8 @@ TclNamespaceEnsembleCmd(
 			continue;
 		    }
 		    do {
-			if (TclListObjGetElementsM(interp, listObj, &len,
-				&listv) != TCL_OK) {
+			if (TclListObjLengthM(interp, listObj, &len
+				) != TCL_OK) {
 			    Tcl_DictObjDone(&search);
 			    if (patchedDict) {
 				Tcl_DecrRefCount(patchedDict);
@@ -582,6 +582,14 @@ TclNamespaceEnsembleCmd(
 			    }
 			    goto freeMapAndError;
 			}
+			if (TclListObjGetElementsM(interp, listObj, &len,
+				&listv) != TCL_OK) {
+			    Tcl_DictObjDone(&search);
+			    if (patchedDict) {
+				Tcl_DecrRefCount(patchedDict);
+			    }
+			    goto freeMapAndError;
+			}
 			cmd = TclGetString(listv[0]);
 			if (!(cmd[0] == ':' && cmd[1] == ':')) {
 			    Tcl_Obj *newList = Tcl_DuplicateObj(listObj);
diff --git a/generic/tclListObj.c b/generic/tclListObj.c
index 776ff0e..80477f7 100644
--- a/generic/tclListObj.c
+++ b/generic/tclListObj.c
@@ -1994,7 +1994,7 @@ int
 Tcl_ListObjLength(
     Tcl_Interp *interp,	/* Used to report errors if not NULL. */
     Tcl_Obj *listObj,	/* List object whose #elements to return. */
-    Tcl_Size *lenPtr)	/* The resulting int is stored here. */
+    Tcl_Size *lenPtr)	/* The resulting length is stored here. */
 {
     ListRep listRep;
 
@@ -2632,7 +2632,7 @@ TclLindexFlat(
 
     /* Handle ArithSeries as special case */
     if (TclHasInternalRep(listObj,&tclArithSeriesType)) {
-	Tcl_WideInt listLen = TclArithSeriesObjLength(listObj);
+	Tcl_Size listLen = TclArithSeriesObjLength(listObj);
 	Tcl_Size index;
 	Tcl_Obj *elemObj = NULL;
 	for (i=0 ; i<indexCount && listObj ; i++) {
diff --git a/generic/tclProc.c b/generic/tclProc.c
index b8c324e..3ada9ea 100644
--- a/generic/tclProc.c
+++ b/generic/tclProc.c
@@ -2508,6 +2508,14 @@ SetLambdaFromAny(
      * length is not 2, then it cannot be converted to lambdaType.
      */
 
+    result = TclListObjLengthM(NULL, objPtr, &objc);
+    if ((result != TCL_OK) || ((objc != 2) && (objc != 3))) {
+	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+		"can't interpret \"%s\" as a lambda expression",
+		Tcl_GetString(objPtr)));
+	Tcl_SetErrorCode(interp, "TCL", "VALUE", "LAMBDA", NULL);
+	return TCL_ERROR;
+    }
     result = TclListObjGetElementsM(NULL, objPtr, &objc, &objv);
     if ((result != TCL_OK) || ((objc != 2) && (objc != 3))) {
 	Tcl_SetObjResult(interp, Tcl_ObjPrintf(
diff --git a/generic/tclTrace.c b/generic/tclTrace.c
index e2be167..3e8844a 100644
--- a/generic/tclTrace.c
+++ b/generic/tclTrace.c
@@ -429,7 +429,7 @@ TraceExecutionObjCmd(
 	 * pointer to its array of element pointers.
 	 */
 
-	result = TclListObjGetElementsM(interp, objv[4], &listLen, &elemPtrs);
+	result = TclListObjLengthM(interp, objv[4], &listLen);
 	if (result != TCL_OK) {
 	    return result;
 	}
@@ -441,6 +441,10 @@ TraceExecutionObjCmd(
 		    NULL);
 	    return TCL_ERROR;
 	}
+	result = TclListObjGetElementsM(interp, objv[4], &listLen, &elemPtrs);
+	if (result != TCL_OK) {
+	    return result;
+	}
 	for (i = 0; i < listLen; i++) {
 	    if (Tcl_GetIndexFromObj(interp, elemPtrs[i], opStrings,
 		    "operation", TCL_EXACT, &index) != TCL_OK) {
@@ -672,7 +676,7 @@ TraceCommandObjCmd(
 	 * pointer to its array of element pointers.
 	 */
 
-	result = TclListObjGetElementsM(interp, objv[4], &listLen, &elemPtrs);
+	result = TclListObjLengthM(interp, objv[4], &listLen);
 	if (result != TCL_OK) {
 	    return result;
 	}
@@ -684,7 +688,10 @@ TraceCommandObjCmd(
 		    NULL);
 	    return TCL_ERROR;
 	}
-
+	result = TclListObjGetElementsM(interp, objv[4], &listLen, &elemPtrs);
+	if (result != TCL_OK) {
+	    return result;
+	}
 	for (i = 0; i < listLen; i++) {
 	    if (Tcl_GetIndexFromObj(interp, elemPtrs[i], opStrings,
 		    "operation", TCL_EXACT, &index) != TCL_OK) {
@@ -873,7 +880,7 @@ TraceVariableObjCmd(
 	 * pointer to its array of element pointers.
 	 */
 
-	result = TclListObjGetElementsM(interp, objv[4], &listLen, &elemPtrs);
+	result = TclListObjLengthM(interp, objv[4], &listLen);
 	if (result != TCL_OK) {
 	    return result;
 	}
@@ -885,6 +892,10 @@ TraceVariableObjCmd(
 		    NULL);
 	    return TCL_ERROR;
 	}
+	result = TclListObjGetElementsM(interp, objv[4], &listLen, &elemPtrs);
+	if (result != TCL_OK) {
+	    return result;
+	}
 	for (i = 0; i < listLen ; i++) {
 	    if (Tcl_GetIndexFromObj(interp, elemPtrs[i], opStrings,
 		    "operation", TCL_EXACT, &index) != TCL_OK) {
diff --git a/generic/tclVar.c b/generic/tclVar.c
index 2a96fb6..c614371 100644
--- a/generic/tclVar.c
+++ b/generic/tclVar.c
@@ -4161,8 +4161,7 @@ ArraySetCmd(
 	int elemLen;
 	Tcl_Obj **elemPtrs, *copyListObj;
 
-	result = TclListObjGetElementsM(interp, arrayElemObj,
-		&elemLen, &elemPtrs);
+	result = TclListObjLengthM(interp, arrayElemObj, &elemLen);
 	if (result != TCL_OK) {
 	    return result;
 	}
@@ -4175,6 +4174,11 @@ ArraySetCmd(
 	if (elemLen == 0) {
 	    goto ensureArray;
 	}
+	result = TclListObjGetElementsM(interp, arrayElemObj,
+		&elemLen, &elemPtrs);
+	if (result != TCL_OK) {
+	    return result;
+	}
 
 	/*
 	 * We needn't worry about traces invalidating arrayPtr: should that be
diff --git a/generic/tclZipfs.c b/generic/tclZipfs.c
index 3b1d787..1b602ea 100644
--- a/generic/tclZipfs.c
+++ b/generic/tclZipfs.c
@@ -3044,7 +3044,7 @@ ZipFSMkZipOrImg(
 	}
     }
     Tcl_IncrRefCount(list);
-    if (TclListObjGetElementsM(interp, list, &lobjc, &lobjv) != TCL_OK) {
+    if (TclListObjLengthM(interp, list, &lobjc) != TCL_OK) {
 	Tcl_DecrRefCount(list);
 	return TCL_ERROR;
     }
@@ -3060,6 +3060,10 @@ ZipFSMkZipOrImg(
 	ZIPFS_ERROR_CODE(interp, "EMPTY");
 	return TCL_ERROR;
     }
+    if (TclListObjGetElementsM(interp, list, &lobjc, &lobjv) != TCL_OK) {
+	Tcl_DecrRefCount(list);
+	return TCL_ERROR;
+    }
     out = Tcl_FSOpenFileChannel(interp, targetFile, "wb", 0755);
     if (out == NULL) {
 	Tcl_DecrRefCount(list);