merge core-8-6-branch. Undo changes to coffbase.txt (they cause overlap with Tk)winFixes

13 files changed, 207 insertions, 105 deletions

diff --git a/generic/tclCmdAH.c b/generic/tclCmdAH.c
index 88cc17d..4c299f8 100644
--- a/generic/tclCmdAH.c
+++ b/generic/tclCmdAH.c
@@ -1597,7 +1597,7 @@ FileAttrIsOwnedCmd(
     Tcl_Obj *const objv[])
 {
 #ifdef __CYGWIN__
-#define geteuid() (short)(geteuid)() 
+#define geteuid() (short)(geteuid)()
 #endif
 #if !defined(_WIN32)
     Tcl_StatBuf buf;
diff --git a/generic/tclCompile.c b/generic/tclCompile.c
index c0203dd..f6b3c52 100644
--- a/generic/tclCompile.c
+++ b/generic/tclCompile.c
@@ -1781,9 +1781,17 @@ CompileCmdLiteral(
     CompileEnv *envPtr)
 {
     int numBytes;
-    const char *bytes = Tcl_GetStringFromObj(cmdObj, &numBytes);
-    int cmdLitIdx = TclRegisterNewCmdLiteral(envPtr, bytes, numBytes);
-    Command *cmdPtr = (Command *) Tcl_GetCommandFromObj(interp, cmdObj);
+    const char *bytes;
+    Command *cmdPtr;
+    int cmdLitIdx, extraLiteralFlags = LITERAL_CMD_NAME;
+
+    cmdPtr = (Command *) Tcl_GetCommandFromObj(interp, cmdObj);
+    if ((cmdPtr != NULL) && (cmdPtr->flags & CMD_VIA_RESOLVER)) {
+	extraLiteralFlags |= LITERAL_UNSHARED;
+    }
+
+    bytes = Tcl_GetStringFromObj(cmdObj, &numBytes);
+    cmdLitIdx = TclRegisterLiteral(envPtr, (char *)bytes, numBytes, extraLiteralFlags);
 
     if (cmdPtr) {
 	TclSetCmdNameObj(interp, TclFetchLiteral(envPtr, cmdLitIdx), cmdPtr);
diff --git a/generic/tclCompile.h b/generic/tclCompile.h
index d5bc86b..ba6ad44 100644
--- a/generic/tclCompile.h
+++ b/generic/tclCompile.h
@@ -1208,6 +1208,7 @@ MODULE_SCOPE int	TclPushProcCallFrame(ClientData clientData,
 
 #define LITERAL_ON_HEAP		0x01
 #define LITERAL_CMD_NAME	0x02
+#define LITERAL_UNSHARED	0x04
 
 /*
  * Form of TclRegisterLiteral with flags == 0. In that case, it is safe to
diff --git a/generic/tclEnsemble.c b/generic/tclEnsemble.c
index 8e5e410..6fedf29 100644
--- a/generic/tclEnsemble.c
+++ b/generic/tclEnsemble.c
@@ -3306,7 +3306,7 @@ CompileToInvokedCommand(
     Tcl_Token *tokPtr;
     Tcl_Obj *objPtr, **words;
     char *bytes;
-    int length, i, numWords, cmdLit;
+    int length, i, numWords, cmdLit, extraLiteralFlags = LITERAL_CMD_NAME;
     DefineLineInformation;
 
     /*
@@ -3349,7 +3349,10 @@ CompileToInvokedCommand(
     objPtr = Tcl_NewObj();
     Tcl_GetCommandFullName(interp, (Tcl_Command) cmdPtr, objPtr);
     bytes = Tcl_GetStringFromObj(objPtr, &length);
-    cmdLit = TclRegisterNewCmdLiteral(envPtr, bytes, length);
+    if ((cmdPtr != NULL) && (cmdPtr->flags & CMD_VIA_RESOLVER)) {
+	extraLiteralFlags |= LITERAL_UNSHARED;
+    }
+    cmdLit = TclRegisterLiteral(envPtr, (char *)bytes, length, extraLiteralFlags);
     TclSetCmdNameObj(interp, TclFetchLiteral(envPtr, cmdLit), cmdPtr);
     TclEmitPush(cmdLit, envPtr);
     TclDecrRefCount(objPtr);
diff --git a/generic/tclExecute.c b/generic/tclExecute.c
index e539161..34d92d3 100644
--- a/generic/tclExecute.c
+++ b/generic/tclExecute.c
@@ -3173,7 +3173,7 @@ TEBCresume(
 	    Tcl_Obj *copyPtr = Tcl_NewListObj(objc - opnd + 1, NULL);
 
 	    Tcl_ListObjAppendElement(NULL, copyPtr, objPtr);
-	    Tcl_ListObjReplace(NULL, copyPtr, LIST_MAX, 0, 
+	    Tcl_ListObjReplace(NULL, copyPtr, LIST_MAX, 0,
 		    objc - opnd, objv + opnd);
 	    Tcl_DecrRefCount(objPtr);
 	    objPtr = copyPtr;
diff --git a/generic/tclInt.h b/generic/tclInt.h
index 4f7ea6e..4d3c0b1 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -1677,11 +1677,13 @@ typedef struct Command {
  * (these last two flags are defined in tcl.h)
  */
 
-#define CMD_IS_DELETED		    0x1
-#define CMD_TRACE_ACTIVE	    0x2
-#define CMD_HAS_EXEC_TRACES	    0x4
-#define CMD_COMPILES_EXPANDED	    0x8
+#define CMD_IS_DELETED		    0x01
+#define CMD_TRACE_ACTIVE	    0x02
+#define CMD_HAS_EXEC_TRACES	    0x04
+#define CMD_COMPILES_EXPANDED	    0x08
 #define CMD_REDEF_IN_PROGRESS	    0x10
+#define CMD_VIA_RESOLVER	    0x20
+
 
 /*
  *----------------------------------------------------------------
diff --git a/generic/tclLiteral.c b/generic/tclLiteral.c
index 03200ca..4ae94a0 100644
--- a/generic/tclLiteral.c
+++ b/generic/tclLiteral.c
@@ -214,7 +214,7 @@ TclCreateLiteral(
 	    if (globalPtrPtr) {
 		*globalPtrPtr = globalPtr;
 	    }
-	    if (flags & LITERAL_ON_HEAP) {
+	    if ((flags & LITERAL_ON_HEAP)) {
 		ckfree(bytes);
 	    }
 	    globalPtr->refCount++;
@@ -222,7 +222,7 @@ TclCreateLiteral(
 	}
     }
     if (!newPtr) {
-	if (flags & LITERAL_ON_HEAP) {
+	if ((flags & LITERAL_ON_HEAP)) {
 	    ckfree(bytes);
 	}
 	return NULL;
@@ -234,14 +234,23 @@ TclCreateLiteral(
      */
 
     TclNewObj(objPtr);
-    Tcl_IncrRefCount(objPtr);
-    if (flags & LITERAL_ON_HEAP) {
+    if ((flags & LITERAL_ON_HEAP)) {
 	objPtr->bytes = bytes;
 	objPtr->length = length;
     } else {
 	TclInitStringRep(objPtr, bytes, length);
     }
 
+    if ((flags & LITERAL_UNSHARED)) {
+	/*
+	 * Make clear, that no global value is returned
+	 */
+	if (globalPtrPtr != NULL) {
+	    *globalPtrPtr = NULL;
+	}
+	return objPtr;
+    }
+
 #ifdef TCL_COMPILE_DEBUG
     if (LookupLiteralEntry((Tcl_Interp *) iPtr, objPtr) != NULL) {
 	Tcl_Panic("%s: literal \"%.*s\" found globally but shouldn't be",
@@ -251,6 +260,7 @@ TclCreateLiteral(
 
     globalPtr = ckalloc(sizeof(LiteralEntry));
     globalPtr->objPtr = objPtr;
+    Tcl_IncrRefCount(objPtr);
     globalPtr->refCount = 1;
     globalPtr->nsPtr = nsPtr;
     globalPtr->nextPtr = globalTablePtr->buckets[globalHash];
@@ -398,7 +408,7 @@ TclRegisterLiteral(
 	if ((objPtr->length == length) && ((length == 0)
 		|| ((objPtr->bytes[0] == bytes[0])
 		&& (memcmp(objPtr->bytes, bytes, (unsigned) length) == 0)))) {
-	    if (flags & LITERAL_ON_HEAP) {
+	    if ((flags & LITERAL_ON_HEAP)) {
 		ckfree(bytes);
 	    }
 	    objIndex = (localPtr - envPtr->literalArrayPtr);
@@ -417,7 +427,7 @@ TclRegisterLiteral(
      * the namespace as the interp's global NS.
      */
 
-    if (flags & LITERAL_CMD_NAME) {
+    if ((flags & LITERAL_CMD_NAME)) {
 	if ((length >= 2) && (bytes[0] == ':') && (bytes[1] == ':')) {
 	    nsPtr = iPtr->globalNsPtr;
 	} else {
@@ -431,12 +441,13 @@ TclRegisterLiteral(
      * Is it in the interpreter's global literal table? If not, create it.
      */
 
+    globalPtr = NULL;
     objPtr = TclCreateLiteral(iPtr, bytes, length, hash, &new, nsPtr, flags,
 	    &globalPtr);
     objIndex = AddLocalLiteralEntry(envPtr, objPtr, localHash);
 
 #ifdef TCL_COMPILE_DEBUG
-    if (globalPtr->refCount < 1) {
+    if (globalPtr != NULL && globalPtr->refCount < 1) {
 	Tcl_Panic("%s: global literal \"%.*s\" had bad refCount %d",
 		"TclRegisterLiteral", (length>60? 60 : length), bytes,
 		globalPtr->refCount);
@@ -1152,13 +1163,6 @@ TclVerifyLocalLiteralTable(
 			"TclVerifyLocalLiteralTable",
 			(length>60? 60 : length), bytes, localPtr->refCount);
 	    }
-	    if (LookupLiteralEntry((Tcl_Interp *) envPtr->iPtr,
-		    localPtr->objPtr) == NULL) {
-		bytes = Tcl_GetStringFromObj(localPtr->objPtr, &length);
-		Tcl_Panic("%s: local literal \"%.*s\" is not global",
-			"TclVerifyLocalLiteralTable",
-			(length>60? 60 : length), bytes);
-	    }
 	    if (localPtr->objPtr->bytes == NULL) {
 		Tcl_Panic("%s: literal has NULL string rep",
 			"TclVerifyLocalLiteralTable");
diff --git a/generic/tclNamesp.c b/generic/tclNamesp.c
index 5930859..a8d351f 100644
--- a/generic/tclNamesp.c
+++ b/generic/tclNamesp.c
@@ -2566,7 +2566,9 @@ Tcl_FindCommand(
 	}
 
 	if (result == TCL_OK) {
+	    ((Command *)cmd)->flags |= CMD_VIA_RESOLVER;
 	    return cmd;
+
 	} else if (result != TCL_CONTINUE) {
 	    return NULL;
 	}
@@ -2658,6 +2660,7 @@ Tcl_FindCommand(
     }
 
     if (cmdPtr != NULL) {
+	cmdPtr->flags  &= ~CMD_VIA_RESOLVER;
 	return (Tcl_Command) cmdPtr;
     }
 
diff --git a/generic/tclObj.c b/generic/tclObj.c
index 628c3a7..29c8e23 100644
--- a/generic/tclObj.c
+++ b/generic/tclObj.c
@@ -4219,7 +4219,10 @@ TclSetCmdNameObj(
     const char *name;
 
     if (objPtr->typePtr == &tclCmdNameType) {
-	return;
+	resPtr = objPtr->internalRep.twoPtrValue.ptr1;
+	if (resPtr != NULL && resPtr->cmdPtr == cmdPtr) {
+	    return;
+	}
     }
 
     cmdPtr->refCount++;
diff --git a/generic/tclTest.c b/generic/tclTest.c
index e33d263..568dd01 100644
--- a/generic/tclTest.c
+++ b/generic/tclTest.c
@@ -7299,24 +7299,83 @@ InterpCmdResolver(
     CallFrame *varFramePtr = iPtr->varFramePtr;
     Proc *procPtr = (varFramePtr->isProcCallFrame & FRAME_IS_PROC) ?
             varFramePtr->procPtr : NULL;
-    Namespace *ns2NsPtr = (Namespace *)
-            Tcl_FindNamespace(interp, "::ns2", NULL, 0);
+    Namespace *callerNsPtr = varFramePtr->nsPtr;
+    Tcl_Command resolvedCmdPtr = NULL;
 
-    if (procPtr && (procPtr->cmdPtr->nsPtr == iPtr->globalNsPtr
-            || (ns2NsPtr && procPtr->cmdPtr->nsPtr == ns2NsPtr))) {
-        const char *callingCmdName =
+    /*
+     * Just do something special on a cmd literal "z" in two cases:
+     *  A)  when the caller is a proc "x", and the proc is either in "::" or in "::ns2".
+     *  B) the caller's namespace is "ctx1" or "ctx2"
+     */
+    if ( (name[0] == 'z') && (name[1] == '\0') ) {
+        Namespace *ns2NsPtr = (Namespace *) Tcl_FindNamespace(interp, "::ns2", NULL, 0);
+
+        if (procPtr != NULL
+            && ((procPtr->cmdPtr->nsPtr == iPtr->globalNsPtr)
+                || (ns2NsPtr != NULL && procPtr->cmdPtr->nsPtr == ns2NsPtr)
+                )
+            ) {
+            /*
+             * Case A)
+             *
+             *    - The context, in which this resolver becomes active, is
+             *      determined by the name of the caller proc, which has to be
+             *      named "x".
+             *
+             *    - To determine the name of the caller proc, the proc is taken
+             *      from the topmost stack frame.
+             *
+             *    - Note that the context is NOT provided during byte-code
+             *      compilation (e.g. in TclProcCompileProc)
+             *
+             *   When these conditions hold, this function resolves the
+             *   passed-in cmd literal into a cmd "y", which is taken from the
+             *   the global namespace (for simplicity).
+             */
+
+            const char *callingCmdName =
                 Tcl_GetCommandName(interp, (Tcl_Command) procPtr->cmdPtr);
 
-        if ((callingCmdName[0] == 'x') && (callingCmdName[1] == '\0')
-                && (name[0] == 'z') && (name[1] == '\0')) {
-            Tcl_Command sourceCmdPtr = Tcl_FindCommand(interp, "y", NULL,
-                    TCL_GLOBAL_ONLY);
+            if ( callingCmdName[0] == 'x' && callingCmdName[1] == '\0' ) {
+                resolvedCmdPtr = Tcl_FindCommand(interp, "y", NULL, TCL_GLOBAL_ONLY);
+            }
+        } else if (callerNsPtr != NULL) {
+            /*
+             * Case B)
+             *
+             *    - The context, in which this resolver becomes active, is
+             *      determined by the name of the parent namespace, which has
+             *      to be named "ctx1" or "ctx2".
+             *
+             *    - To determine the name of the parent namesace, it is taken
+             *      from the 2nd highest stack frame.
+             *
+             *    - Note that the context can be provided during byte-code
+             *      compilation (e.g. in TclProcCompileProc)
+             *
+             *   When these conditions hold, this function resolves the
+             *   passed-in cmd literal into a cmd "y" or "Y" depending on the
+             *   context. The resolved procs are taken from the the global
+             *   namespace (for simplicity).
+             */
+
+            CallFrame *parentFramePtr = varFramePtr->callerPtr;
+            char *context = parentFramePtr != NULL ? parentFramePtr->nsPtr->name : "(NULL)";
 
-            if (sourceCmdPtr != NULL) {
-                *rPtr = sourceCmdPtr;
-                return TCL_OK;
+            if (strcmp(context, "ctx1") == 0 && (name[0] == 'z') && (name[1] == '\0')) {
+                resolvedCmdPtr = Tcl_FindCommand(interp, "y", NULL, TCL_GLOBAL_ONLY);
+                /* fprintf(stderr, "... y ==> %p\n", resolvedCmdPtr);*/
+
+            } else if (strcmp(context, "ctx2") == 0 && (name[0] == 'z') && (name[1] == '\0')) {
+                resolvedCmdPtr = Tcl_FindCommand(interp, "Y", NULL, TCL_GLOBAL_ONLY);
+                /*fprintf(stderr, "... Y ==> %p\n", resolvedCmdPtr);*/
             }
         }
+
+        if (resolvedCmdPtr != NULL) {
+            *rPtr = resolvedCmdPtr;
+            return TCL_OK;
+        }
     }
     return TCL_CONTINUE;
 }
@@ -7449,9 +7508,16 @@ TestInterpResolverCmd(
     int idx;
 #define RESOLVER_KEY "testInterpResolver"
 
-    if (objc != 2) {
-        Tcl_WrongNumArgs(interp, 1, objv, "up|down");
- 	return TCL_ERROR;
+    if ((objc < 2) || (objc > 3)) {
+	Tcl_WrongNumArgs(interp, 1, objv, "up|down ?interp?");
+	return TCL_ERROR;
+    }
+    if (objc == 3) {
+	interp = Tcl_GetSlave(interp, Tcl_GetString(objv[2]));
+	if (interp == NULL) {
+	    Tcl_AppendResult(interp, "provided interpreter not found", NULL);
+	    return TCL_ERROR;
+	}
     }
     if (Tcl_GetIndexFromObj(interp, objv[1], table, "operation", TCL_EXACT,
             &idx) != TCL_OK) {
diff --git a/generic/tclUtf.c b/generic/tclUtf.c
index b878149..68119a4 100644
--- a/generic/tclUtf.c
+++ b/generic/tclUtf.c
@@ -73,16 +73,7 @@ static const unsigned char totalBytes[256] = {
 #else
     1,1,1,1,1,1,1,1,
 #endif
-#if TCL_UTF_MAX > 4
-    5,5,5,5,
-#else
-    1,1,1,1,
-#endif
-#if TCL_UTF_MAX > 5
-    6,6,6,6
-#else
-    1,1,1,1
-#endif
+    1,1,1,1,1,1,1,1
 };
 
 /*
@@ -111,14 +102,14 @@ INLINE static int
 UtfCount(
     int ch)			/* The Tcl_UniChar whose size is returned. */
 {
-    if ((ch > 0) && (ch < UNICODE_SELF)) {
+    if ((unsigned)(ch - 1) < (UNICODE_SELF - 1)) {
 	return 1;
     }
     if (ch <= 0x7FF) {
 	return 2;
     }
 #if TCL_UTF_MAX > 3
-    if ((ch > 0xFFFF) && (ch <= 0x10FFFF)) {
+    if (((unsigned)(ch - 0x10000) <= 0xfffff)) {
 	return 4;
     }
 #endif
@@ -152,7 +143,7 @@ Tcl_UniCharToUtf(
 				 * large enough to hold the UTF-8 character
 				 * (at most TCL_UTF_MAX bytes). */
 {
-    if ((ch > 0) && (ch < UNICODE_SELF)) {
+    if ((unsigned)(ch - 1) < (UNICODE_SELF - 1)) {
 	buf[0] = (char) ch;
 	return 1;
     }
@@ -180,11 +171,7 @@ Tcl_UniCharToUtf(
 		}
 	    }
 #endif
-	three:
-	    buf[2] = (char) ((ch | 0x80) & 0xBF);
-	    buf[1] = (char) (((ch >> 6) | 0x80) & 0xBF);
-	    buf[0] = (char) ((ch >> 12) | 0xE0);
-	    return 3;
+	    goto three;
 	}
 
 #if TCL_UTF_MAX > 3
@@ -199,7 +186,11 @@ Tcl_UniCharToUtf(
     }
 
     ch = 0xFFFD;
-    goto three;
+three:
+    buf[2] = (char) ((ch | 0x80) & 0xBF);
+    buf[1] = (char) (((ch >> 6) | 0x80) & 0xBF);
+    buf[0] = (char) ((ch >> 12) | 0xE0);
+    return 3;
 }
 
 /*
@@ -314,9 +305,6 @@ Tcl_UtfToUniChar(
 	 * A two-byte-character lead-byte not followed by trail-byte
 	 * represents itself.
 	 */
-
-	*chPtr = (Tcl_UniChar) byte;
-	return 1;
     } else if (byte < 0xF0) {
 	if (((src[1] & 0xC0) == 0x80) && ((src[2] & 0xC0) == 0x80)) {
 	    /*
@@ -332,31 +320,23 @@ Tcl_UtfToUniChar(
 	 * A three-byte-character lead-byte not followed by two trail-bytes
 	 * represents itself.
 	 */
-
-	*chPtr = (Tcl_UniChar) byte;
-	return 1;
     }
 #if TCL_UTF_MAX > 3
-    {
-	int ch, total, trail;
-
-	total = totalBytes[byte];
-	trail = total - 1;
-	if (trail > 0) {
-	    ch = byte & (0x3F >> trail);
-	    do {
-		src++;
-		if ((*src & 0xC0) != 0x80) {
-		    *chPtr = byte;
-		    return 1;
-		}
-		ch <<= 6;
-		ch |= (*src & 0x3F);
-		trail--;
-	    } while (trail > 0);
-	    *chPtr = ch;
-	    return total;
+    else if (byte < 0xF8) {
+	if (((src[1] & 0xC0) == 0x80) && ((src[2] & 0xC0) == 0x80) && ((src[3] & 0xC0) == 0x80)) {
+	    /*
+	     * Four-byte-character lead byte followed by three trail bytes.
+	     */
+
+	    *chPtr = (Tcl_UniChar) (((byte & 0x0E) << 18) | ((src[1] & 0x3F) << 12)
+		    | ((src[2] & 0x3F) << 6) | (src[3] & 0x3F));
+	    return 4;
 	}
+
+	/*
+	 * A three-byte-character lead-byte not followed by two trail-bytes
+	 * represents itself.
+	 */
     }
 #endif
 
diff --git a/generic/tclVar.c b/generic/tclVar.c
index 2adffbc..46a1da6 100644
--- a/generic/tclVar.c
+++ b/generic/tclVar.c
@@ -5193,13 +5193,16 @@ TclDeleteNamespaceVars(
 	VarHashRefCount(varPtr)++;	/* Make sure we get to remove from
 					 * hash. */
 	Tcl_GetVariableFullName(interp, (Tcl_Var) varPtr, objPtr);
-	UnsetVarStruct(varPtr, NULL, iPtr, /* part1 */ objPtr, NULL, flags,
-		-1);
-	Tcl_DecrRefCount(objPtr);	/* Free no longer needed obj */
+	UnsetVarStruct(varPtr, NULL, iPtr, /* part1 */ objPtr,
+		NULL, flags, -1);
 
 	/*
-	 * Remove the variable from the table and force it undefined in case
-	 * an unset trace brought it back from the dead.
+	 * We just unset the variable. However, an unset trace might
+	 * have re-set it, or might have re-established traces on it.
+	 * This namespace and its vartable are going away unconditionally,
+	 * so we cannot let such things linger. That would be a leak.
+	 *
+	 * First we destroy all traces. ...
 	 */
 
 	if (TclIsVarTraced(varPtr)) {
@@ -5223,6 +5226,17 @@ TclDeleteNamespaceVars(
 		}
 	    }
 	}
+
+	/*
+	 * ...and then, if the variable still holds a value, we unset it
+	 * again. This time with no traces left, we're sure it goes away.
+	 */
+
+	if (!TclIsVarUndefined(varPtr)) {
+	    UnsetVarStruct(varPtr, NULL, iPtr, /* part1 */ objPtr,
+		    NULL, flags, -1);
+	}
+	Tcl_DecrRefCount(objPtr); /* free no longer needed obj */
 	VarHashRefCount(varPtr)--;
 	VarHashDeleteEntry(varPtr);
     }
diff --git a/generic/tclZlib.c b/generic/tclZlib.c
index dac47cf..c9d7b88 100644
--- a/generic/tclZlib.c
+++ b/generic/tclZlib.c
@@ -2864,7 +2864,7 @@ ZlibTransformClose(
     Tcl_Interp *interp)
 {
     ZlibChannelData *cd = instanceData;
-    int e, result = TCL_OK;
+    int e, written, result = TCL_OK;
 
     /*
      * Delete the support timer.
@@ -2882,6 +2882,17 @@ ZlibTransformClose(
 	    cd->outStream.next_out = (Bytef *) cd->outBuffer;
 	    cd->outStream.avail_out = (unsigned) cd->outAllocated;
 	    e = deflate(&cd->outStream, Z_FINISH);
+	    written = cd->outAllocated - cd->outStream.avail_out;
+
+	    /*
+	     * Can't be sure that deflate() won't declare the buffer to be
+	     * full (with Z_BUF_ERROR) so handle that case.
+	     */
+
+	    if (e == Z_BUF_ERROR) {
+		e = Z_OK;
+		written = cd->outAllocated;
+	    }
 	    if (e != Z_OK && e != Z_STREAM_END) {
 		/* TODO: is this the right way to do errors on close? */
 		if (!TclInThreadExit()) {
@@ -2890,20 +2901,17 @@ ZlibTransformClose(
 		result = TCL_ERROR;
 		break;
 	    }
-	    if (cd->outStream.avail_out != (unsigned) cd->outAllocated) {
-		if (Tcl_WriteRaw(cd->parent, cd->outBuffer,
-			cd->outAllocated - cd->outStream.avail_out) < 0) {
-		    /* TODO: is this the right way to do errors on close?
-		     * Note: when close is called from FinalizeIOSubsystem
-		     * then interp may be NULL */
-		    if (!TclInThreadExit() && interp) {
-			Tcl_SetObjResult(interp, Tcl_ObjPrintf(
-				"error while finalizing file: %s",
-				Tcl_PosixError(interp)));
-		    }
-		    result = TCL_ERROR;
-		    break;
+	    if (written && Tcl_WriteRaw(cd->parent, cd->outBuffer, written) < 0) {
+		/* TODO: is this the right way to do errors on close?
+		 * Note: when close is called from FinalizeIOSubsystem then
+		 * interp may be NULL */
+		if (!TclInThreadExit() && interp) {
+		    Tcl_SetObjResult(interp, Tcl_ObjPrintf(
+			    "error while finalizing file: %s",
+			    Tcl_PosixError(interp)));
 		}
+		result = TCL_ERROR;
+		break;
 	    }
 	} while (e != Z_STREAM_END);
 	(void) deflateEnd(&cd->outStream);
@@ -3084,7 +3092,17 @@ ZlibTransformOutput(
 	e = deflate(&cd->outStream, Z_NO_FLUSH);
 	produced = cd->outAllocated - cd->outStream.avail_out;
 
-	if (e == Z_OK && produced > 0) {
+	if ((e == Z_OK && produced > 0) || e == Z_BUF_ERROR) {
+	    /*
+	     * deflate() indicates that it is out of space by returning
+	     * Z_BUF_ERROR; in that case, we must write the whole buffer out
+	     * and retry to compress what is left.
+	     */
+
+	    if (e == Z_BUF_ERROR) {
+		produced = cd->outAllocated;
+		e = Z_OK;
+	    }
 	    if (Tcl_WriteRaw(cd->parent, cd->outBuffer, produced) < 0) {
 		*errorCodePtr = Tcl_GetErrno();
 		return -1;