From 76871708808853f6b59ece6e2a6d6ec4a594df70 Mon Sep 17 00:00:00 2001
From: pooryorick <com.digitalsmarties@pooryorick.com>
Date: Thu, 2 Sep 2021 22:38:32 +0000
Subject: Backport fixes for [ccc448a6bfd5], namespace ensemble subcommand name
 prefix matching and a subsequent error results in a segmentation fault.

---
 generic/tclEnsemble.c | 20 +++++++++++++++++++-
 generic/tclIndexObj.c | 18 +++++-------------
 generic/tclInt.h      |  1 +
 generic/tclNamesp.c   |  5 +++--
 tests/namespace.test  | 18 ++++++++++++++++++
 5 files changed, 46 insertions(+), 16 deletions(-)

diff --git a/generic/tclEnsemble.c b/generic/tclEnsemble.c
index ccd43b9..7d060b0 100644
--- a/generic/tclEnsemble.c
+++ b/generic/tclEnsemble.c
@@ -2201,6 +2201,18 @@ TclSpellFix(
     TclNRAddCallback(interp, TclNRReleaseValues, fix, NULL, NULL, NULL);
 }
 
+Tcl_Obj *const *TclEnsembleGetRewriteValues(
+    Tcl_Interp *interp		/* Current interpreter. */
+)
+{
+    Interp *iPtr = (Interp *) interp;
+    Tcl_Obj *const *origObjv = iPtr->ensembleRewrite.sourceObjs;
+    if (origObjv[0] == NULL) {
+	origObjv = (Tcl_Obj *const *)origObjv[2];
+    }
+    return origObjv;
+}
+
 /*
  *----------------------------------------------------------------------
  *
@@ -2225,12 +2237,18 @@ TclFetchEnsembleRoot(
     int objc,
     int *objcPtr)
 {
+    Tcl_Obj *const *sourceObjs;
     Interp *iPtr = (Interp *) interp;
 
     if (iPtr->ensembleRewrite.sourceObjs) {
 	*objcPtr = objc + iPtr->ensembleRewrite.numRemovedObjs
 		- iPtr->ensembleRewrite.numInsertedObjs;
-	return iPtr->ensembleRewrite.sourceObjs;
+	if (iPtr->ensembleRewrite.sourceObjs[0] == NULL) {
+	    sourceObjs = (Tcl_Obj *const *)iPtr->ensembleRewrite.sourceObjs[1];
+	} else {
+	    sourceObjs = iPtr->ensembleRewrite.sourceObjs;
+	}
+	return sourceObjs;
     }
     *objcPtr = objc;
     return objv;
diff --git a/generic/tclIndexObj.c b/generic/tclIndexObj.c
index 48ebb69..c33caf8 100644
--- a/generic/tclIndexObj.c
+++ b/generic/tclIndexObj.c
@@ -887,27 +887,19 @@ Tcl_WrongNumArgs(
     }
 
     /*
-     * Check to see if we are processing an ensemble implementation, and if so
-     * rewrite the results in terms of how the ensemble was invoked.
+     * If processing an an ensemble implementation, rewrite the results in
+     * terms of how the ensemble was invoked.
      */
 
     if (iPtr->ensembleRewrite.sourceObjs != NULL) {
 	int toSkip = iPtr->ensembleRewrite.numInsertedObjs;
 	int toPrint = iPtr->ensembleRewrite.numRemovedObjs;
-	Tcl_Obj *const *origObjv = iPtr->ensembleRewrite.sourceObjs;
+	Tcl_Obj *const *origObjv = TclEnsembleGetRewriteValues(interp);
 
 	/*
-	 * Check for spelling fixes, and substitute the fixed values.
-	 */
-
-	if (origObjv[0] == NULL) {
-	    origObjv = (Tcl_Obj *const *)origObjv[2];
-	}
-
-	/*
-	 * We only know how to do rewriting if all the replaced objects are
+	 * Only do rewrite the command if all the replaced objects are
 	 * actually arguments (in objv) to this function. Otherwise it just
-	 * gets too complicated and we'd be better off just giving a slightly
+	 * gets too complicated and it's to just give a slightly
 	 * confusing error message...
 	 */
 
diff --git a/generic/tclInt.h b/generic/tclInt.h
index b561cbd..6c3a05d 100644
--- a/generic/tclInt.h
+++ b/generic/tclInt.h
@@ -2993,6 +2993,7 @@ MODULE_SCOPE char *	TclDStringAppendDString(Tcl_DString *dsPtr,
 MODULE_SCOPE Tcl_Obj *	TclDStringToObj(Tcl_DString *dsPtr);
 MODULE_SCOPE Tcl_Obj *const *TclFetchEnsembleRoot(Tcl_Interp *interp,
 			    Tcl_Obj *const *objv, int objc, int *objcPtr);
+MODULE_SCOPE Tcl_Obj *const *TclEnsembleGetRewriteValues(Tcl_Interp *interp);
 MODULE_SCOPE Tcl_Namespace *TclEnsureNamespace(Tcl_Interp *interp,
 			    Tcl_Namespace *namespacePtr);
 MODULE_SCOPE void	TclFinalizeAllocSubsystem(void);
diff --git a/generic/tclNamesp.c b/generic/tclNamesp.c
index 5dc9659..2aed628 100644
--- a/generic/tclNamesp.c
+++ b/generic/tclNamesp.c
@@ -4921,8 +4921,9 @@ TclLogCommandInfo(
 				 * command (must be <= command). */
     const char *command,	/* First character in command that generated
 				 * the error. */
-    int length,			/* Number of bytes in command (-1 means use
-				 * all bytes up to first null byte). */
+    int length,			/* Number of bytes in command (TCL_INDEX_NONE
+				 * means use all bytes up to first null byte).
+				*/
     const unsigned char *pc,    /* Current pc of bytecode execution context */
     Tcl_Obj **tosPtr)		/* Current stack of bytecode execution
 				 * context */
diff --git a/tests/namespace.test b/tests/namespace.test
index 6eabf61..c98ad4a 100644
--- a/tests/namespace.test
+++ b/tests/namespace.test
@@ -1908,6 +1908,24 @@ test namespace-42.10 {
     unset -nocomplain lst
 } -returnCodes error -match glob -result {invalid command name *three*}
 
+
+test namespace-42.11 {
+	ensembles: prefix matching segmentation fault
+
+	issue ccc448a6bfd59cbd
+} -body {
+    namespace eval n1 {
+        namespace ensemble create
+        namespace export *
+        proc p1 args {error success}
+    }
+    # segmentation fault only occurs in the non-byte-compiled path, so avoid
+    # byte compilation
+    set cmd {namespace eva n1 {[namespace parent]::n1 p1}}
+    {*}$cmd
+} -returnCodes error -result success
+
+
 test namespace-43.1 {ensembles: dict-driven} {
     namespace eval ns {
 	namespace export x*
-- 
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