Add some more Tcl_Attempt* functionscore-attemptgetstring

11 files changed, 386 insertions, 55 deletions

diff --git a/generic/tcl.decls b/generic/tcl.decls
index 05849fc..3f90629 100644
--- a/generic/tcl.decls
+++ b/generic/tcl.decls
@@ -104,6 +104,9 @@ declare 20 {
 declare 21 {
     int Tcl_DbIsShared(Tcl_Obj *objPtr, const char *file, int line)
 }
+declare 22 {
+    char *Tcl_DbGetStringFromObj(Tcl_Obj *objPtr, Tcl_Size *lengthPtr, const char *file, int line)
+}
 declare 23 {
     Tcl_Obj *Tcl_DbNewByteArrayObj(const unsigned char *bytes,
 	    Tcl_Size numBytes, const char *file, int line)
@@ -193,6 +196,9 @@ declare 55 {
 declare 56 {
     Tcl_Obj *Tcl_NewStringObj(const char *bytes, Tcl_Size length)
 }
+declare 57 {
+    Tcl_Obj *Tcl_AttemptNewStringObj(const char *bytes, Tcl_Size length)
+}
 declare 58 {
     unsigned char *Tcl_SetByteArrayLength(Tcl_Obj *objPtr, Tcl_Size numBytes)
 }
@@ -1038,6 +1044,15 @@ declare 338 {
 declare 339 {
     Tcl_Size Tcl_WriteObj(Tcl_Channel chan, Tcl_Obj *objPtr)
 }
+declare 340 {
+    char *Tcl_AttemptGetStringFromObj(Tcl_Obj *objPtr, Tcl_Size *lengthPtr)
+}
+declare 341 {
+    char  *Tcl_AttemptSetStringObj(Tcl_Obj *objPtr, const char *bytes, Tcl_Size length)
+}
+declare 342 {
+    Tcl_Obj *Tcl_AttemptDuplicateObj(Tcl_Obj *objPtr)
+}
 declare 343 {
     void Tcl_AlertNotifier(void *clientData)
 }
diff --git a/generic/tclArithSeries.c b/generic/tclArithSeries.c
index c075369..3f4b98b 100755
--- a/generic/tclArithSeries.c
+++ b/generic/tclArithSeries.c
@@ -1175,9 +1175,7 @@ UpdateStringOfArithSeries(
 	    Tcl_PrintDouble(NULL,d,tmp);
 	    elen = strlen(tmp);
 	    if (bytlen > TCL_SIZE_MAX - elen) {
-		/* overflow, todo: check we could use some representation instead of the panic
-		 * to signal it is too large for string representation, because too heavy */
-		Tcl_Panic("UpdateStringOfArithSeries: too large to represent");
+		goto repTooLarge;
 	    }
 	    bytlen += elen;
 	}
@@ -1188,8 +1186,16 @@ UpdateStringOfArithSeries(
      * Pass 2: generate the string repr.
      */
 
-    p = srep = Tcl_InitStringRep(arithSeriesObjPtr, NULL, bytlen);
-    TclOOM(p, bytlen+1);
+    p = srep = TclAttemptInitStringRep(arithSeriesObjPtr, NULL, bytlen);
+    if (!p) {
+    repTooLarge:
+	if (arithSeriesObjPtr->bytes) {
+	    Tcl_Free(arithSeriesObjPtr->bytes);
+	    arithSeriesObjPtr->bytes = 0;
+	}
+	arithSeriesObjPtr->length = bytlen;
+	return;
+    }
 
     if (!arithSeriesRepPtr->isDouble) {
 	for (i = 0; i < arithSeriesRepPtr->len; i++) {
diff --git a/generic/tclCmdMZ.c b/generic/tclCmdMZ.c
index ca813d7..1eb37b0 100644
--- a/generic/tclCmdMZ.c
+++ b/generic/tclCmdMZ.c
@@ -2681,6 +2681,10 @@ StringEqualCmd(
 
     objv += objc-2;
     match = TclStringCmp(objv[0], objv[1], 1, nocase, reqlength);
+    if (match == INT_MIN) {
+	Tcl_AppendResult(interp, "memory allocation error", (char *)NULL);
+	return TCL_ERROR;
+    }
     Tcl_SetObjResult(interp, Tcl_NewBooleanObj(match ? 0 : 1));
     return TCL_OK;
 }
@@ -2726,6 +2730,10 @@ StringCmpCmd(
 
     objv += objc-2;
     match = TclStringCmp(objv[0], objv[1], 0, nocase, reqlength);
+    if (match == INT_MIN) {
+	Tcl_AppendResult(interp, "memory allocation error", (char *)NULL);
+	return TCL_ERROR;
+    }
     Tcl_SetObjResult(interp, Tcl_NewWideIntObj(match));
     return TCL_OK;
 }
diff --git a/generic/tclDecls.h b/generic/tclDecls.h
index 47f6b9a..b9e2ab8 100644
--- a/generic/tclDecls.h
+++ b/generic/tclDecls.h
@@ -107,7 +107,10 @@ EXTERN void		Tcl_DbIncrRefCount(Tcl_Obj *objPtr, const char *file,
 /* 21 */
 EXTERN int		Tcl_DbIsShared(Tcl_Obj *objPtr, const char *file,
 				int line);
-/* Slot 22 is reserved */
+/* 22 */
+EXTERN char *		Tcl_DbGetStringFromObj(Tcl_Obj *objPtr,
+				Tcl_Size *lengthPtr, const char *file,
+				int line);
 /* 23 */
 EXTERN Tcl_Obj *	Tcl_DbNewByteArrayObj(const unsigned char *bytes,
 				Tcl_Size numBytes, const char *file,
@@ -189,7 +192,9 @@ EXTERN Tcl_Obj *	Tcl_NewListObj(Tcl_Size objc, Tcl_Obj *const objv[]);
 EXTERN Tcl_Obj *	Tcl_NewObj(void);
 /* 56 */
 EXTERN Tcl_Obj *	Tcl_NewStringObj(const char *bytes, Tcl_Size length);
-/* Slot 57 is reserved */
+/* 57 */
+EXTERN Tcl_Obj *	Tcl_AttemptNewStringObj(const char *bytes,
+				Tcl_Size length);
 /* 58 */
 EXTERN unsigned char *	Tcl_SetByteArrayLength(Tcl_Obj *objPtr,
 				Tcl_Size numBytes);
@@ -894,9 +899,14 @@ EXTERN Tcl_Size		Tcl_WriteChars(Tcl_Channel chan, const char *src,
 				Tcl_Size srcLen);
 /* 339 */
 EXTERN Tcl_Size		Tcl_WriteObj(Tcl_Channel chan, Tcl_Obj *objPtr);
-/* Slot 340 is reserved */
-/* Slot 341 is reserved */
-/* Slot 342 is reserved */
+/* 340 */
+EXTERN char *		Tcl_AttemptGetStringFromObj(Tcl_Obj *objPtr,
+				Tcl_Size *lengthPtr);
+/* 341 */
+EXTERN char *		Tcl_AttemptSetStringObj(Tcl_Obj *objPtr,
+				const char *bytes, Tcl_Size length);
+/* 342 */
+EXTERN Tcl_Obj *	Tcl_AttemptDuplicateObj(Tcl_Obj *objPtr);
 /* 343 */
 EXTERN void		Tcl_AlertNotifier(void *clientData);
 /* 344 */
@@ -1907,7 +1917,7 @@ typedef struct TclStubs {
     void (*tcl_DbDecrRefCount) (Tcl_Obj *objPtr, const char *file, int line); /* 19 */
     void (*tcl_DbIncrRefCount) (Tcl_Obj *objPtr, const char *file, int line); /* 20 */
     int (*tcl_DbIsShared) (Tcl_Obj *objPtr, const char *file, int line); /* 21 */
-    void (*reserved22)(void);
+    char * (*tcl_DbGetStringFromObj) (Tcl_Obj *objPtr, Tcl_Size *lengthPtr, const char *file, int line); /* 22 */
     Tcl_Obj * (*tcl_DbNewByteArrayObj) (const unsigned char *bytes, Tcl_Size numBytes, const char *file, int line); /* 23 */
     Tcl_Obj * (*tcl_DbNewDoubleObj) (double doubleValue, const char *file, int line); /* 24 */
     Tcl_Obj * (*tcl_DbNewListObj) (Tcl_Size objc, Tcl_Obj *const *objv, const char *file, int line); /* 25 */
@@ -1942,7 +1952,7 @@ typedef struct TclStubs {
     void (*reserved54)(void);
     Tcl_Obj * (*tcl_NewObj) (void); /* 55 */
     Tcl_Obj * (*tcl_NewStringObj) (const char *bytes, Tcl_Size length); /* 56 */
-    void (*reserved57)(void);
+    Tcl_Obj * (*tcl_AttemptNewStringObj) (const char *bytes, Tcl_Size length); /* 57 */
     unsigned char * (*tcl_SetByteArrayLength) (Tcl_Obj *objPtr, Tcl_Size numBytes); /* 58 */
     void (*tcl_SetByteArrayObj) (Tcl_Obj *objPtr, const unsigned char *bytes, Tcl_Size numBytes); /* 59 */
     void (*tcl_SetDoubleObj) (Tcl_Obj *objPtr, double doubleValue); /* 60 */
@@ -2225,9 +2235,9 @@ typedef struct TclStubs {
     Tcl_Size (*tcl_UtfToUpper) (char *src); /* 337 */
     Tcl_Size (*tcl_WriteChars) (Tcl_Channel chan, const char *src, Tcl_Size srcLen); /* 338 */
     Tcl_Size (*tcl_WriteObj) (Tcl_Channel chan, Tcl_Obj *objPtr); /* 339 */
-    void (*reserved340)(void);
-    void (*reserved341)(void);
-    void (*reserved342)(void);
+    char * (*tcl_AttemptGetStringFromObj) (Tcl_Obj *objPtr, Tcl_Size *lengthPtr); /* 340 */
+    char * (*tcl_AttemptSetStringObj) (Tcl_Obj *objPtr, const char *bytes, Tcl_Size length); /* 341 */
+    Tcl_Obj * (*tcl_AttemptDuplicateObj) (Tcl_Obj *objPtr); /* 342 */
     void (*tcl_AlertNotifier) (void *clientData); /* 343 */
     void (*tcl_ServiceModeHook) (int mode); /* 344 */
     int (*tcl_UniCharIsAlnum) (int ch); /* 345 */
@@ -2635,7 +2645,8 @@ extern const TclStubs *tclStubsPtr;
 	(tclStubsPtr->tcl_DbIncrRefCount) /* 20 */
 #define Tcl_DbIsShared \
 	(tclStubsPtr->tcl_DbIsShared) /* 21 */
-/* Slot 22 is reserved */
+#define Tcl_DbGetStringFromObj \
+	(tclStubsPtr->tcl_DbGetStringFromObj) /* 22 */
 #define Tcl_DbNewByteArrayObj \
 	(tclStubsPtr->tcl_DbNewByteArrayObj) /* 23 */
 #define Tcl_DbNewDoubleObj \
@@ -2696,7 +2707,8 @@ extern const TclStubs *tclStubsPtr;
 	(tclStubsPtr->tcl_NewObj) /* 55 */
 #define Tcl_NewStringObj \
 	(tclStubsPtr->tcl_NewStringObj) /* 56 */
-/* Slot 57 is reserved */
+#define Tcl_AttemptNewStringObj \
+	(tclStubsPtr->tcl_AttemptNewStringObj) /* 57 */
 #define Tcl_SetByteArrayLength \
 	(tclStubsPtr->tcl_SetByteArrayLength) /* 58 */
 #define Tcl_SetByteArrayObj \
@@ -3219,9 +3231,12 @@ extern const TclStubs *tclStubsPtr;
 	(tclStubsPtr->tcl_WriteChars) /* 338 */
 #define Tcl_WriteObj \
 	(tclStubsPtr->tcl_WriteObj) /* 339 */
-/* Slot 340 is reserved */
-/* Slot 341 is reserved */
-/* Slot 342 is reserved */
+#define Tcl_AttemptGetStringFromObj \
+	(tclStubsPtr->tcl_AttemptGetStringFromObj) /* 340 */
+#define Tcl_AttemptSetStringObj \
+	(tclStubsPtr->tcl_AttemptSetStringObj) /* 341 */
+#define Tcl_AttemptDuplicateObj \
+	(tclStubsPtr->tcl_AttemptDuplicateObj) /* 342 */
 #define Tcl_AlertNotifier \
 	(tclStubsPtr->tcl_AlertNotifier) /* 343 */
 #define Tcl_ServiceModeHook \
@@ -4010,6 +4025,8 @@ extern const TclStubs *tclStubsPtr;
 
 #define Tcl_GetString(objPtr) \
 	Tcl_GetStringFromObj(objPtr, (Tcl_Size *)NULL)
+#define Tcl_AttemptGetString(objPtr) \
+	Tcl_AttemptGetStringFromObj(objPtr, (Tcl_Size *)NULL)
 #define Tcl_GetUnicode(objPtr) \
 	Tcl_GetUnicodeFromObj(objPtr, (Tcl_Size *)NULL)
 #undef Tcl_GetIndexFromObjStruct
@@ -4063,6 +4080,11 @@ extern const TclStubs *tclStubsPtr;
 #   undef Tcl_AttemptRealloc
 #   define Tcl_AttemptRealloc(x,y) \
     (Tcl_AttemptDbCkrealloc((x), (y), __FILE__, __LINE__))
+#   define Tcl_Alloc(x) \
+    (Tcl_DbCkalloc((x), __FILE__, __LINE__))
+#   undef Tcl_GetStringFromObj
+#   define Tcl_GetStringFromObj(x,y) \
+    (Tcl_DbGetStringFromObj((x), (y), __FILE__, __LINE__))
 #endif /* !TCL_MEM_DEBUG */
 
 #define Tcl_NewLongObj(value) Tcl_NewWideIntObj((long)(value))
diff --git a/generic/tclDictObj.c b/generic/tclDictObj.c
index ae214d2..0217343 100644
--- a/generic/tclDictObj.c
+++ b/generic/tclDictObj.c
@@ -520,7 +520,17 @@ UpdateStringOfDict(
     if (numElems <= LOCAL_SIZE) {
 	flagPtr = localFlags;
     } else {
-	flagPtr = (char *)Tcl_Alloc(numElems);
+	flagPtr = (char *)Tcl_AttemptAlloc(numElems);
+	if (!flagPtr) {
+	    dictPtr->length = numElems;
+	allocError:
+	    /* Allocation error. Just give up. */
+	    if (dictPtr->bytes) {
+		Tcl_Free(dictPtr->bytes);
+		dictPtr->bytes = NULL;
+	    }
+	    return;
+	}
     }
     for (i=0,cPtr=dict->entryChainHead; i<numElems; i+=2,cPtr=cPtr->nextPtr) {
 	/*
@@ -530,11 +540,19 @@ UpdateStringOfDict(
 
 	flagPtr[i] = ( i ? TCL_DONT_QUOTE_HASH : 0 );
 	keyPtr = (Tcl_Obj *)Tcl_GetHashKey(&dict->table, &cPtr->entry);
-	elem = TclGetStringFromObj(keyPtr, &length);
+	elem = TclAttemptGetStringFromObj(keyPtr, &length);
+	if (!elem) {
+	    dictPtr->length = keyPtr->length;
+	    goto allocError;
+	}
 	bytesNeeded += TclScanElement(elem, length, flagPtr+i);
 	flagPtr[i+1] = TCL_DONT_QUOTE_HASH;
 	valuePtr = (Tcl_Obj *)Tcl_GetHashValue(&cPtr->entry);
-	elem = TclGetStringFromObj(valuePtr, &length);
+	elem = TclAttemptGetStringFromObj(valuePtr, &length);
+	if (!elem) {
+	    dictPtr->length = valuePtr->length;
+	    goto allocError;
+	}
 	bytesNeeded += TclScanElement(elem, length, flagPtr+i+1);
     }
     bytesNeeded += numElems;
@@ -544,7 +562,10 @@ UpdateStringOfDict(
      */
 
     dst = Tcl_InitStringRep(dictPtr, NULL, bytesNeeded - 1);
-    TclOOM(dst, bytesNeeded);
+    if (!dst) {
+	dictPtr->length = bytesNeeded;
+	goto allocError;
+    }
     for (i=0,cPtr=dict->entryChainHead; i<numElems; i+=2,cPtr=cPtr->nextPtr) {
 	if (i) {
 	    flagPtr[i] |= TCL_DONT_QUOTE_HASH;
diff --git a/generic/tclInt.h b/generic/tclInt.h
index 30f841d..d2a8b9b 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -4441,6 +4441,14 @@ MODULE_SCOPE void	TclDbInitNewObj(Tcl_Obj *objPtr, const char *file,
 	    ? (*(lenPtr) = (objPtr)->length, (objPtr)->bytes)		\
 	    : (Tcl_GetStringFromObj)((objPtr), (lenPtr)))
 
+#define TclAttemptGetString(objPtr) \
+    ((objPtr)->bytes? (objPtr)->bytes : Tcl_AttemptGetString(objPtr))
+
+#define TclAttemptGetStringFromObj(objPtr, lenPtr) \
+    ((objPtr)->bytes							\
+	    ? (*(lenPtr) = (objPtr)->length, (objPtr)->bytes)		\
+	    : (Tcl_AttemptGetStringFromObj)((objPtr), (lenPtr)))
+
 /*
  *----------------------------------------------------------------
  * Macro used by the Tcl core to clean out an object's internal
@@ -4812,6 +4820,20 @@ MODULE_SCOPE Tcl_LibraryInitProc Tcl_ABSListTest_Init;
 	TCL_DTRACE_OBJ_CREATE(objPtr);					\
     } while (0)
 
+#define TclAttemptNewStringObj(objPtr, s, len) \
+    do {								\
+	TclIncrObjsAllocated();						\
+	TclAllocObjStorage(objPtr);					\
+	(objPtr)->refCount = 0;						\
+	if (TclAttemptInitStringRep((objPtr), (s), (len))) { \
+	    (objPtr)->typePtr = NULL;					\
+	    TCL_DTRACE_OBJ_CREATE(objPtr);					\
+	} else { \
+	    Tcl_DecrRefCount(objPtr); \
+	    (objPtr) = NULL; \
+	} \
+    } while (0)
+
 #else /* TCL_MEM_DEBUG */
 #define TclNewIntObj(objPtr, w) \
     (objPtr) = Tcl_NewWideIntObj(w)
@@ -4839,6 +4861,10 @@ MODULE_SCOPE Tcl_LibraryInitProc Tcl_ABSListTest_Init;
 
 #define TclNewStringObj(objPtr, s, len) \
     (objPtr) = Tcl_NewStringObj((s), (len))
+
+#define TclAttemptNewStringObj(objPtr, s, len) \
+    (objPtr) = Tcl_AttemptNewStringObj((s), (len))
+
 #endif /* TCL_MEM_DEBUG */
 
 /*
diff --git a/generic/tclListObj.c b/generic/tclListObj.c
index aec2fbb..f6bd1ca 100644
--- a/generic/tclListObj.c
+++ b/generic/tclListObj.c
@@ -3537,14 +3537,25 @@ UpdateStringOfList(
 	flagPtr = localFlags;
     } else {
 	/* We know numElems <= LIST_MAX, so this is safe. */
-	flagPtr = (char *)Tcl_Alloc(numElems);
+	flagPtr = (char *)Tcl_AttemptAlloc(numElems);
+	if (!flagPtr) {
+	    listObj->length = numElems;
+	allocError:
+	    /* Allocation error. Just give up. */
+	    if (listObj->bytes) {
+		Tcl_Free(listObj->bytes);
+		listObj->bytes = NULL;
+	    }
+	    return;
+	}
     }
     for (i = 0; i < numElems; i++) {
 	flagPtr[i] = (i ? TCL_DONT_QUOTE_HASH : 0);
-	elem = TclGetStringFromObj(elemPtrs[i], &length);
+	elem = TclAttemptGetStringFromObj(elemPtrs[i], &length);
 	bytesNeeded += TclScanElement(elem, length, flagPtr+i);
 	if (bytesNeeded > SIZE_MAX - numElems) {
-	    Tcl_Panic("max size for a Tcl value (%" TCL_Z_MODIFIER "u bytes) exceeded", SIZE_MAX);
+	    listObj->length = bytesNeeded;
+	    goto allocError;
 	}
     }
     bytesNeeded += numElems - 1;
@@ -3553,13 +3564,20 @@ UpdateStringOfList(
      * Pass 2: copy into string rep buffer.
      */
 
-    start = dst = Tcl_InitStringRep(listObj, NULL, bytesNeeded);
-    TclOOM(dst, bytesNeeded);
+    start = dst = TclAttemptInitStringRep(listObj, NULL, bytesNeeded);
+    if (!start) {
+	listObj->length = bytesNeeded;
+	goto allocError;
+    }
     for (i = 0; i < numElems; i++) {
 	if (i) {
 	    flagPtr[i] |= TCL_DONT_QUOTE_HASH;
 	}
-	elem = TclGetStringFromObj(elemPtrs[i], &length);
+	elem = TclAttemptGetStringFromObj(elemPtrs[i], &length);
+	if (!elem) {
+		listObj->length = elemPtrs[i]->length;
+		goto allocError;
+	}
 	dst += TclConvertElement(elem, length, dst, flagPtr[i]);
 	*dst++ = ' ';
     }
diff --git a/generic/tclMain.c b/generic/tclMain.c
index e604a60..53c39e7 100644
--- a/generic/tclMain.c
+++ b/generic/tclMain.c
@@ -533,13 +533,20 @@ Tcl_MainEx(
 	    } else if (is.tty) {
 		resultPtr = Tcl_GetObjResult(interp);
 		Tcl_IncrRefCount(resultPtr);
-		(void)Tcl_GetStringFromObj(resultPtr, &length);
-		chan = Tcl_GetStdChannel(TCL_STDOUT);
-		if ((length > 0) && chan) {
-		    if (Tcl_WriteObj(chan, resultPtr) < 0) {
-			Tcl_WriteChars(chan, ENCODING_ERROR, -1);
+		(void)Tcl_AttemptGetStringFromObj(resultPtr, &length);
+		if (!resultPtr->bytes) {
+		    chan = Tcl_GetStdChannel(TCL_STDERR);
+		    if (chan) {
+			Tcl_WriteChars(chan, "Memory allocation error\n", -1);
+		    }
+		} else {
+		    chan = Tcl_GetStdChannel(TCL_STDOUT);
+		    if ((length > 0) && chan) {
+			if (Tcl_WriteObj(chan, resultPtr) < 0) {
+			    Tcl_WriteChars(chan, ENCODING_ERROR, -1);
+			}
+			Tcl_WriteChars(chan, "\n", 1);
 		    }
-		    Tcl_WriteChars(chan, "\n", 1);
 		}
 		Tcl_DecrRefCount(resultPtr);
 	    }
@@ -813,12 +820,19 @@ StdinProc(
 	chan = Tcl_GetStdChannel(TCL_STDOUT);
 
 	Tcl_IncrRefCount(resultPtr);
-	(void)Tcl_GetStringFromObj(resultPtr, &length);
-	if ((length > 0) && (chan != NULL)) {
-	    if (Tcl_WriteObj(chan, resultPtr) < 0) {
-		Tcl_WriteChars(chan, ENCODING_ERROR, -1);
+	(void)Tcl_AttemptGetStringFromObj(resultPtr, &length);
+	if (!resultPtr->bytes) {
+	    chan = Tcl_GetStdChannel(TCL_STDERR);
+	    if (chan) {
+		Tcl_WriteChars(chan, "Memory allocation error\n", -1);
+	    }
+	} else {
+	    if ((length > 0) && (chan != NULL)) {
+		if (Tcl_WriteObj(chan, resultPtr) < 0) {
+		    Tcl_WriteChars(chan, ENCODING_ERROR, -1);
+		}
+		Tcl_WriteChars(chan, "\n", 1);
 	    }
-	    Tcl_WriteChars(chan, "\n", 1);
 	}
 	Tcl_DecrRefCount(resultPtr);
     }
diff --git a/generic/tclObj.c b/generic/tclObj.c
index f9fc83f..87017d8 100644
--- a/generic/tclObj.c
+++ b/generic/tclObj.c
@@ -1555,6 +1555,25 @@ TclObjBeingDeleted(
 	}								\
     }
 
+#define AttemptSetDuplicateObj(dupPtr, objPtr)					\
+    {									\
+	const Tcl_ObjType *typePtr = (objPtr)->typePtr;			\
+	const char *bytes = (objPtr)->bytes;				\
+	if (bytes) {							\
+	    TclAttemptInitStringRep((dupPtr), bytes, (objPtr)->length);	\
+	} else {							\
+	    (dupPtr)->bytes = NULL;					\
+	}								\
+	if (typePtr) {							\
+	    if (typePtr->dupIntRepProc) {				\
+		typePtr->dupIntRepProc((objPtr), (dupPtr));		\
+	    } else {							\
+		(dupPtr)->internalRep = (objPtr)->internalRep;		\
+		(dupPtr)->typePtr = typePtr;				\
+	    }								\
+	}								\
+    }
+
 Tcl_Obj *
 Tcl_DuplicateObj(
     Tcl_Obj *objPtr)		/* The object to duplicate. */
@@ -1566,6 +1585,21 @@ Tcl_DuplicateObj(
     return dupPtr;
 }
 
+Tcl_Obj *
+Tcl_AttemptDuplicateObj(
+    Tcl_Obj *objPtr)		/* The object to duplicate. */
+{
+    Tcl_Obj *dupPtr;
+
+    TclNewObj(dupPtr);
+    AttemptSetDuplicateObj(dupPtr, objPtr);
+    if (!dupPtr->bytes) {
+	Tcl_DecrRefCount(dupPtr);
+	dupPtr = NULL;
+    }
+    return dupPtr;
+}
+
 void
 TclSetDuplicateObj(
     Tcl_Obj *dupPtr,
@@ -1675,8 +1709,11 @@ Tcl_GetStringFromObj(
 		    objPtr->typePtr->name);
 	}
 	objPtr->typePtr->updateStringProc(objPtr);
-	if (objPtr->bytes == NULL
-		|| objPtr->bytes[objPtr->length] != '\0') {
+	if (objPtr->bytes == NULL) {
+	    Tcl_Panic("UpdateStringProc for type '%s' "
+		    "failed to allocate %" TCL_SIZE_MODIFIER "d bytes",
+		    objPtr->typePtr->name, objPtr->length);
+	} else if (objPtr->bytes[objPtr->length] != '\0') {
 	    Tcl_Panic("UpdateStringProc for type '%s' "
 		    "failed to create a valid string rep",
 		    objPtr->typePtr->name);
@@ -1687,6 +1724,89 @@ Tcl_GetStringFromObj(
     }
     return objPtr->bytes;
 }
+
+char *
+Tcl_DbGetStringFromObj(
+    Tcl_Obj *objPtr,		/* Object whose string rep byte pointer should
+				 * be returned. */
+    Tcl_Size *lengthPtr,	/* If non-NULL, the location where the string
+				 * rep's byte array length should * be stored.
+				 * If NULL, no length is stored. */
+    const char *file,
+    int line)
+{
+    if (objPtr->bytes == NULL) {
+	/*
+	 * Note we do not check for objPtr->typePtr == NULL.  An invariant
+	 * of a properly maintained Tcl_Obj is that at least  one of
+	 * objPtr->bytes and objPtr->typePtr must not be NULL.  If broken
+	 * extensions fail to maintain that invariant, we can crash here.
+	 */
+
+	if (objPtr->typePtr->updateStringProc == NULL) {
+	    /*
+	     * Those Tcl_ObjTypes which choose not to define an
+	     * updateStringProc must be written in such a way that
+	     * (objPtr->bytes) never becomes NULL.
+	     */
+	    Tcl_Panic("UpdateStringProc should not be invoked for type %s. %s:%d",
+		    objPtr->typePtr->name, file, line);
+	}
+	objPtr->typePtr->updateStringProc(objPtr);
+	if (objPtr->bytes == NULL) {
+	    Tcl_Panic("UpdateStringProc for type '%s' "
+		    "failed to allocate %" TCL_SIZE_MODIFIER "d bytes. %s:%d",
+		    objPtr->typePtr->name, objPtr->length, file, line);
+	} else if (objPtr->bytes[objPtr->length] != '\0') {
+	    Tcl_Panic("UpdateStringProc for type '%s' "
+		    "failed to create a valid string rep. %s:%d",
+		    objPtr->typePtr->name, file, line);
+	}
+    }
+    if (lengthPtr != NULL) {
+	*lengthPtr = objPtr->length;
+    }
+    return objPtr->bytes;
+}
+
+char *
+Tcl_AttemptGetStringFromObj(
+    Tcl_Obj *objPtr,		/* Object whose string rep byte pointer should
+				 * be returned. */
+    Tcl_Size *lengthPtr)	/* If non-NULL, the location where the string
+				 * rep's byte array length should * be stored.
+				 * If NULL, no length is stored. */
+{
+    if (objPtr->bytes == NULL) {
+	/*
+	 * Note we do not check for objPtr->typePtr == NULL.  An invariant
+	 * of a properly maintained Tcl_Obj is that at least  one of
+	 * objPtr->bytes and objPtr->typePtr must not be NULL.  If broken
+	 * extensions fail to maintain that invariant, we can crash here.
+	 */
+
+	if (objPtr->typePtr->updateStringProc == NULL) {
+	    /*
+	     * Those Tcl_ObjTypes which choose not to define an
+	     * updateStringProc must be written in such a way that
+	     * (objPtr->bytes) never becomes NULL.
+	     */
+	    Tcl_Panic("UpdateStringProc should not be invoked for type %s",
+		    objPtr->typePtr->name);
+	}
+	objPtr->typePtr->updateStringProc(objPtr);
+	if (objPtr->bytes != NULL
+		&& objPtr->bytes[objPtr->length] != '\0') {
+	    Tcl_Panic("UpdateStringProc for type '%s' "
+		    "failed to create a valid string rep",
+		    objPtr->typePtr->name);
+	}
+    }
+    if (lengthPtr != NULL) {
+	*lengthPtr = objPtr->bytes ? objPtr->length : -1;
+    }
+    return objPtr->bytes;
+}
 
 /*
  *----------------------------------------------------------------------
diff --git a/generic/tclStringObj.c b/generic/tclStringObj.c
index 93d0981..8ecc5cc 100644
--- a/generic/tclStringObj.c
+++ b/generic/tclStringObj.c
@@ -253,6 +253,24 @@ Tcl_NewStringObj(
     return objPtr;
 }
 #endif /* TCL_MEM_DEBUG */
+
+Tcl_Obj *
+Tcl_AttemptNewStringObj(
+    const char *bytes,		/* Points to the first of the length bytes
+				 * used to initialize the new object. */
+    Tcl_Size length)		/* The number of bytes to copy from "bytes"
+				 * when initializing the new object. If -1,
+				 * use bytes up to the first NUL byte. */
+{
+    Tcl_Obj *objPtr;
+
+    if (length < 0) {
+	length = (bytes? strlen(bytes) : 0);
+    }
+    TclAttemptNewStringObj(objPtr, bytes, length);
+    return objPtr;
+}
+
 
 /*
  *----------------------------------------------------------------------
@@ -901,6 +919,58 @@ Tcl_SetStringObj(
 /*
  *----------------------------------------------------------------------
  *
+ * Tcl_AttemptSetStringObj --
+ *
+ *	Modify an object to hold a string that is a copy of the bytes
+ *	indicated by the byte pointer and length arguments.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	The object's string representation will be set to a copy of the
+ *	"length" bytes starting at "bytes". If "length" is TCL_INDEX_NONE, use bytes
+ *	up to the first NUL byte; i.e., assume "bytes" points to a C-style
+ *	NUL-terminated string. The object's old string and internal
+ *	representations are freed and the object's type is set NULL.
+ *
+ *----------------------------------------------------------------------
+ */
+
+char *
+Tcl_AttemptSetStringObj(
+    Tcl_Obj *objPtr,		/* Object whose internal rep to init. */
+    const char *bytes,		/* Points to the first of the length bytes
+				 * used to initialize the object. */
+    Tcl_Size length)		/* The number of bytes to copy from "bytes"
+				 * when initializing the object. If -1,
+				 * use bytes up to the first NUL byte.*/
+{
+    if (Tcl_IsShared(objPtr)) {
+	Tcl_Panic("%s called with shared object", "Tcl_SetStringObj");
+    }
+
+    /*
+     * Set the type to NULL and free any internal rep for the old type.
+     */
+
+    TclFreeInternalRep(objPtr);
+
+    /*
+     * Free any old string rep, then set the string rep to a copy of the
+     * length bytes starting at "bytes".
+     */
+
+    TclInvalidateStringRep(objPtr);
+    if (length == TCL_INDEX_NONE) {
+	length = (bytes ? strlen(bytes) : 0);
+    }
+    return TclAttemptInitStringRep(objPtr, bytes, length);
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
  * Tcl_SetObjLength --
  *
  *	Changes the length of the string representation of objPtr.
@@ -3723,7 +3793,7 @@ TclStringCmp(
 		case -1:
 		    s1 = "";
 		    s1len = 0;
-		    s2 = TclGetStringFromObj(value2Ptr, &s2len);
+		    s2 = TclAttemptGetStringFromObj(value2Ptr, &s2len);
 		    break;
 		case 0:
 		    match = -1;
@@ -3738,7 +3808,7 @@ TclStringCmp(
 		case -1:
 		    s2 = "";
 		    s2len = 0;
-		    s1 = TclGetStringFromObj(value1Ptr, &s1len);
+		    s1 = TclAttemptGetStringFromObj(value1Ptr, &s1len);
 		    break;
 		case 0:
 		    match = 1;
@@ -3749,8 +3819,11 @@ TclStringCmp(
 		    goto matchdone;
 		}
 	    } else {
-		s1 = TclGetStringFromObj(value1Ptr, &s1len);
-		s2 = TclGetStringFromObj(value2Ptr, &s2len);
+		s1 = TclAttemptGetStringFromObj(value1Ptr, &s1len);
+		s2 = TclAttemptGetStringFromObj(value2Ptr, &s2len);
+	    }
+	    if (!s1 || !s2) {
+		return INT_MIN;
 	    }
 	    if (!nocase && checkEq && reqlength < 0) {
 		/*
@@ -4504,7 +4577,7 @@ DupStringInternalRep(
 
 static int
 SetStringFromAny(
-    TCL_UNUSED(Tcl_Interp *),
+    Tcl_Interp *interp,
     Tcl_Obj *objPtr)		/* The object to convert. */
 {
     if (!TclHasInternalRep(objPtr, &tclStringType)) {
@@ -4514,7 +4587,11 @@ SetStringFromAny(
 	 * Convert whatever we have into an untyped value. Just A String.
 	 */
 
-	(void) TclGetString(objPtr);
+	(void)TclAttemptGetString(objPtr);
+	if (!objPtr->bytes) {
+	    Tcl_AppendResult(interp, "allocation error", (char *)NULL);
+	    return TCL_ERROR;
+	}
 	TclFreeInternalRep(objPtr);
 
 	/*
@@ -4615,7 +4692,11 @@ ExtendStringRepWithUnicode(
 	size += TclUtfCount(unicode[i]);
     }
     if (size < 0) {
-	Tcl_Panic("max size for a Tcl value (%" TCL_SIZE_MODIFIER "d bytes) exceeded", TCL_SIZE_MAX);
+	if (objPtr->bytes) {
+	    Tcl_Free(objPtr->bytes);
+	    objPtr->bytes = NULL;
+	}
+    return TCL_ERROR;
     }
 
     /*
diff --git a/generic/tclStubInit.c b/generic/tclStubInit.c
index 8839e0b..6a742d5 100644
--- a/generic/tclStubInit.c
+++ b/generic/tclStubInit.c
@@ -829,7 +829,7 @@ const TclStubs tclStubs = {
     Tcl_DbDecrRefCount, /* 19 */
     Tcl_DbIncrRefCount, /* 20 */
     Tcl_DbIsShared, /* 21 */
-    0, /* 22 */
+    Tcl_DbGetStringFromObj, /* 22 */
     Tcl_DbNewByteArrayObj, /* 23 */
     Tcl_DbNewDoubleObj, /* 24 */
     Tcl_DbNewListObj, /* 25 */
@@ -864,7 +864,7 @@ const TclStubs tclStubs = {
     0, /* 54 */
     Tcl_NewObj, /* 55 */
     Tcl_NewStringObj, /* 56 */
-    0, /* 57 */
+    Tcl_AttemptNewStringObj, /* 57 */
     Tcl_SetByteArrayLength, /* 58 */
     Tcl_SetByteArrayObj, /* 59 */
     Tcl_SetDoubleObj, /* 60 */
@@ -1147,9 +1147,9 @@ const TclStubs tclStubs = {
     Tcl_UtfToUpper, /* 337 */
     Tcl_WriteChars, /* 338 */
     Tcl_WriteObj, /* 339 */
-    0, /* 340 */
-    0, /* 341 */
-    0, /* 342 */
+    Tcl_AttemptGetStringFromObj, /* 340 */
+    Tcl_AttemptSetStringObj, /* 341 */
+    Tcl_AttemptDuplicateObj, /* 342 */
     Tcl_AlertNotifier, /* 343 */
     Tcl_ServiceModeHook, /* 344 */
     Tcl_UniCharIsAlnum, /* 345 */