[3600328]: Fix problems caused by buggy [array] compilation inside a buggy

ensemble compilation (which had the net result of producing *very* wrong code).

3 files changed, 37 insertions, 6 deletions

diff --git a/ChangeLog b/ChangeLog
index 23cd2a5..e56d8df 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2013-01-17  Donal K. Fellows  <dkf@users.sf.net>
+
+	* generic/tclCompCmds.c (PushVarName): [Bug 3600328]: Added mechanism
+	for suppressing compilation of variables when we couldn't cope with
+	the results. Useful for some [array] subcommands.
+	* generic/tclEnsemble.c (CompileToCompiledCommand): Must restore the
+	compilation environment when a command compiler fails.
+
 2013-01-16  Donal K. Fellows  <dkf@users.sf.net>
 
 	* generic/tclZlib.c (TclZlibInit): [Bug 3601086]: Register the config
diff --git a/generic/tclCompCmds.c b/generic/tclCompCmds.c
index 752db93..503f339 100644
--- a/generic/tclCompCmds.c
+++ b/generic/tclCompCmds.c
@@ -107,6 +107,7 @@ static int		CompileDictEachCmd(Tcl_Interp *interp,
  */
 
 #define TCL_NO_LARGE_INDEX 1	/* Do not return localIndex value > 255 */
+#define TCL_NO_ELEMENT 2	/* Do not push the array element. */
 
 /*
  * The structures below define the AuxData types defined in this file.
@@ -259,7 +260,7 @@ TclCompileArrayExistsCmd(
     }
 
     tokenPtr = TokenAfter(parsePtr->tokenPtr);
-    PushVarNameWord(interp, tokenPtr, envPtr, 0,
+    PushVarNameWord(interp, tokenPtr, envPtr, TCL_NO_ELEMENT,
 	    &localIndex, &simpleVarName, &isScalar, 1);
     if (!isScalar) {
 	return TCL_ERROR;
@@ -294,7 +295,14 @@ TclCompileArraySetCmd(
     }
 
     tokenPtr = TokenAfter(parsePtr->tokenPtr);
-    PushVarNameWord(interp, tokenPtr, envPtr, 0,
+    if (envPtr->procPtr == NULL) {
+	Tcl_Token *tokPtr = TokenAfter(tokenPtr);
+
+	if (tokPtr->type != TCL_TOKEN_SIMPLE_WORD || tokPtr[1].size != 0) {
+	    return TCL_ERROR;
+	}
+    }
+    PushVarNameWord(interp, tokenPtr, envPtr, TCL_NO_ELEMENT,
 	    &localIndex, &simpleVarName, &isScalar, 1);
     if (!isScalar) {
 	return TCL_ERROR;
@@ -437,7 +445,7 @@ TclCompileArrayUnsetCmd(
 	return TCL_ERROR;
     }
 
-    PushVarNameWord(interp, tokenPtr, envPtr, 0,
+    PushVarNameWord(interp, tokenPtr, envPtr, TCL_NO_ELEMENT,
 	    &localIndex, &simpleVarName, &isScalar, 1);
     if (!isScalar) {
 	return TCL_ERROR;
@@ -6006,7 +6014,7 @@ PushVarName(
     Tcl_Interp *interp,		/* Used for error reporting. */
     Tcl_Token *varTokenPtr,	/* Points to a variable token. */
     CompileEnv *envPtr,		/* Holds resulting instructions. */
-    int flags,			/* TCL_NO_LARGE_INDEX. */
+    int flags,			/* TCL_NO_LARGE_INDEX | TCL_NO_ELEMENT. */
     int *localIndexPtr,		/* Must not be NULL. */
     int *simpleVarNamePtr,	/* Must not be NULL. */
     int *isScalarPtr,		/* Must not be NULL. */
@@ -6187,10 +6195,11 @@ PushVarName(
 	}
 
 	/*
-	 * Compile the element script, if any.
+	 * Compile the element script, if any, and only if not inhibited. [Bug
+	 * 3600328]
 	 */
 
-	if (elName != NULL) {
+	if (elName != NULL && !(flags & TCL_NO_ELEMENT)) {
 	    if (elNameChars) {
 		envPtr->line = line;
 		envPtr->clNext = clNext;
diff --git a/generic/tclEnsemble.c b/generic/tclEnsemble.c
index 058590a..88de9f3 100644
--- a/generic/tclEnsemble.c
+++ b/generic/tclEnsemble.c
@@ -3056,6 +3056,9 @@ CompileToCompiledCommand(
     Tcl_Parse synthetic;
     Tcl_Token *tokenPtr;
     int result, i;
+    int savedNumCmds = envPtr->numCommands;
+    int savedStackDepth = envPtr->currStackDepth;
+    unsigned savedCodeNext = envPtr->codeNext - envPtr->codeStart;
 
     if (cmdPtr->compileProc == NULL) {
 	return TCL_ERROR;
@@ -3110,6 +3113,17 @@ CompileToCompiledCommand(
     result = cmdPtr->compileProc(interp, &synthetic, cmdPtr, envPtr);
 
     /*
+     * If our target fails to compile, revert the number of commands and the
+     * pointer to the place to issue the next instruction. [Bug 3600328]
+     */
+
+    if (result != TCL_OK) {
+	envPtr->numCommands = savedNumCmds;
+	envPtr->currStackDepth = savedStackDepth;
+	envPtr->codeNext = envPtr->codeStart + savedCodeNext;
+    }
+
+    /*
      * Clean up if necessary.
      */