From 50eeabb1014676f4bcc1fe38a06a5d3ef8806044 Mon Sep 17 00:00:00 2001
From: "jan.nijtmans" <nijtmans@users.sourceforge.net>
Date: Wed, 19 Jul 2023 13:04:51 +0000
Subject: [PATCH 1/2] Bugfix for escape-encoding, 'stolen' from TIP #671 branch

---
 generic/tclEncoding.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/generic/tclEncoding.c b/generic/tclEncoding.c
index 539b5206678..deaabaa3486 100644
--- a/generic/tclEncoding.c
+++ b/generic/tclEncoding.c
@@ -3961,9 +3961,10 @@ EscapeToUtfProc(
 	    if ((checked == dataPtr->numSubTables + 2)
 		    || (flags & TCL_ENCODING_END)) {
 		if (!PROFILE_STRICT(flags)) {
+		    unsigned skip = longest > left ? left : longest;
 		    /* Unknown escape sequence */
 		    dst += Tcl_UniCharToUtf(UNICODE_REPLACE_CHAR, dst);
-		    src += longest;
+		    src += skip;
 		    continue;
 		}
 		result = TCL_CONVERT_SYNTAX;

From 515bd7c0e7439f19f59c33be1ff8089de8f4417f Mon Sep 17 00:00:00 2001
From: "jan.nijtmans" <nijtmans@users.sourceforge.net>
Date: Wed, 19 Jul 2023 14:23:31 +0000
Subject: [PATCH 2/2] Improve error-reporting possibilities for
 Tcl_ExternalToUtfDStringEx/Tcl_UtfToExternalDStringEx in case no interpreter
 is available, by setting "errno".

---
 generic/tclEncoding.c | 21 +++++++++++++++------
 generic/tclListObj.c  |  4 ++--
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/generic/tclEncoding.c b/generic/tclEncoding.c
index deaabaa3486..83510ccce33 100644
--- a/generic/tclEncoding.c
+++ b/generic/tclEncoding.c
@@ -1290,6 +1290,7 @@ Tcl_ExternalToUtfDStringEx(
 		"Parameter error: TCL_ENCODING_{START,STOP} bits set in flags.",
 		TCL_INDEX_NONE));
 	Tcl_SetErrorCode(interp, "TCL", "ENCODING", "ILLEGALFLAGS", NULL);
+	errno = EINVAL;
 	return TCL_ERROR;
     }
 
@@ -1333,17 +1334,20 @@ Tcl_ExternalToUtfDStringEx(
 		/* Caller wants error message on failure */
 		if (result != TCL_OK && interp != NULL) {
 		    char buf[TCL_INTEGER_SPACE];
-		    snprintf(buf, sizeof(buf), "%u", nBytesProcessed);
+		    snprintf(buf, sizeof(buf), "%" TCL_SIZE_MODIFIER "u", nBytesProcessed);
 		    Tcl_SetObjResult(
 			interp,
 			Tcl_ObjPrintf("unexpected byte sequence starting at index %"
-				      "u: '\\x%02X'",
+				      TCL_SIZE_MODIFIER "u: '\\x%02X'",
 				      nBytesProcessed,
 				      UCHAR(srcStart[nBytesProcessed])));
 		    Tcl_SetErrorCode(
 			interp, "TCL", "ENCODING", "ILLEGALSEQUENCE", buf, NULL);
 		}
 	    }
+	    if (result != TCL_OK) {
+		errno = (result == TCL_CONVERT_NOSPACE) ? ENOMEM : EILSEQ;
+	    }
 	    return result;
 	}
 
@@ -1527,7 +1531,7 @@ Tcl_UtfToExternalDString(
  *	The parameter flags controls the behavior, if any of the bytes in
  *	the source buffer are invalid or cannot be represented in the
  *	target encoding. It should be composed by OR-ing the following:
- *	- *At most one* of TCL_ENCODING_PROFILE{DEFAULT,TCL8,STRICT}
+ *	- *At most one* of TCL_ENCODING_PROFILE_*
  *	- TCL_ENCODING_STOPONERROR: Backward compatibility. Sets the profile
  *	  to TCL_ENCODING_PROFILE_STRICT overriding any specified profile flags
  *
@@ -1590,6 +1594,7 @@ Tcl_UtfToExternalDStringEx(
 		"Parameter error: TCL_ENCODING_{START,STOP} bits set in flags.",
 		TCL_INDEX_NONE));
 	Tcl_SetErrorCode(interp, "TCL", "ENCODING", "ILLEGALFLAGS", NULL);
+	errno = EINVAL;
 	return TCL_ERROR;
     }
 
@@ -1630,21 +1635,25 @@ Tcl_UtfToExternalDStringEx(
 	    } else {
 		/* Caller wants error message on failure */
 		if (result != TCL_OK && interp != NULL) {
-		    int pos = Tcl_NumUtfChars(srcStart, nBytesProcessed);
+		    Tcl_Size pos = Tcl_NumUtfChars(srcStart, nBytesProcessed);
 		    int ucs4;
 		    char buf[TCL_INTEGER_SPACE];
 		    TclUtfToUCS4(&srcStart[nBytesProcessed], &ucs4);
-		    snprintf(buf, sizeof(buf), "%u", nBytesProcessed);
+		    snprintf(buf, sizeof(buf), "%" TCL_SIZE_MODIFIER "u", nBytesProcessed);
 		    Tcl_SetObjResult(
 			interp,
 			Tcl_ObjPrintf(
-			    "unexpected character at index %d: 'U+%06X'",
+			    "unexpected character at index %" TCL_SIZE_MODIFIER
+			    "u: 'U+%06X'",
 			    pos,
 			    ucs4));
 		    Tcl_SetErrorCode(interp, "TCL", "ENCODING", "ILLEGALSEQUENCE",
 				     buf, NULL);
 		}
 	    }
+	    if (result != TCL_OK) {
+		errno = (result == TCL_CONVERT_NOSPACE) ? ENOMEM : EILSEQ;
+	    }
 	    return result;
 	}
 
diff --git a/generic/tclListObj.c b/generic/tclListObj.c
index 2f433c5f46c..f1b525882e5 100644
--- a/generic/tclListObj.c
+++ b/generic/tclListObj.c
@@ -3448,8 +3448,8 @@ UpdateStringOfList(
      * Mark the list as being canonical; although it will now have a string
      * rep, it is one we derived through proper "canonical" quoting and so
      * it's known to be free from nasties relating to [concat] and [eval].
-     * However, we only do this if 
-     * 
+     * However, we only do this if
+     *
      * (a) the store is not shared as a shared store may be referenced by
      * multiple lists with different string reps. (see [a366c6efee]), AND
      *