2 files changed, 21 insertions, 8 deletions

diff --git a/editors/sed.c b/editors/sed.c
index 48b0dbf67..02a527b4a 100644
--- a/editors/sed.c
+++ b/editors/sed.c
@@ -246,7 +246,6 @@ static void cleanup_outname(void)
 }
 
 /* strcpy, replacing "\from" with 'to'. If to is NUL, replacing "\any" with 'any' */
-
 static unsigned parse_escapes(char *dest, const char *string, int len, char from, char to)
 {
         char *d = dest;
@@ -276,7 +275,7 @@ static unsigned parse_escapes(char *dest, const char *string, int len, char from
         return d - dest;
 }
 
-static char *copy_parsing_escapes(const char *string, int len)
+static char *copy_parsing_escapes(const char *string, int len, char delim)
 {
         const char *s;
         char *dest = xmalloc(len + 1);
@@ -287,10 +286,15 @@ static char *copy_parsing_escapes(const char *string, int len)
                 len = parse_escapes(dest, string, len, s[1], s[0]);
                 string = dest;
         }
+        if (delim) {
+                /* we additionally unescape any instances of escaped delimiter.
+                 * For example, in 's+9\++X+' the pattern is "9+", not "9\+".
+                 */
+                len = parse_escapes(dest, string, len, delim, delim);
+        }
         return dest;
 }
 
-
 /*
  * index_of_next_unescaped_regexp_delim - walks left to right through a string
  * beginning at a specified index and returns the index of the next regular
@@ -347,12 +351,11 @@ static int parse_regex_delim(const char *cmdstr, char **match, char **replace)
 
         /* save the match string */
         idx = index_of_next_unescaped_regexp_delim(delimiter, cmdstr_ptr);
-        *match = copy_parsing_escapes(cmdstr_ptr, idx);
-
+        *match = copy_parsing_escapes(cmdstr_ptr, idx, delimiter);
         /* save the replacement string */
         cmdstr_ptr += idx + 1;
         idx = index_of_next_unescaped_regexp_delim(- (int)delimiter, cmdstr_ptr);
-        *replace = copy_parsing_escapes(cmdstr_ptr, idx);
+        *replace = copy_parsing_escapes(cmdstr_ptr, idx, 0);
 
         return ((cmdstr_ptr - cmdstr) + idx);
 }
@@ -380,7 +383,7 @@ static int get_address(const char *my_str, int *linenum, regex_t ** regex)
                         delimiter = *++pos;
                 next = index_of_next_unescaped_regexp_delim(delimiter, ++pos);
                 if (next != 0) {
-                        temp = copy_parsing_escapes(pos, next);
+                        temp = copy_parsing_escapes(pos, next, 0);
                         G.previous_regex_ptr = *regex = xzalloc(sizeof(regex_t));
                         xregcomp(*regex, temp, G.regex_type);
                         free(temp);
@@ -575,7 +578,7 @@ static const char *parse_cmd_args(sed_cmd_t *sed_cmd, const char *cmdstr)
                         cmdstr++;
                 }
                 len = strlen(cmdstr);
-                sed_cmd->string = copy_parsing_escapes(cmdstr, len);
+                sed_cmd->string = copy_parsing_escapes(cmdstr, len, 0);
                 cmdstr += len;
                 /* "\anychar" -> "anychar" */
                 parse_escapes(sed_cmd->string, sed_cmd->string, -1, '\0', '\0');
diff --git a/testsuite/sed.tests b/testsuite/sed.tests
index e62b839f7..440996a21 100755
--- a/testsuite/sed.tests
+++ b/testsuite/sed.tests
@@ -324,6 +324,16 @@ testing "sed zero chars match/replace logic must not falsely trigger here 2" \
         "sed 's/ *$/_/g'" \
         "qwerty_\n" "" "qwerty\n"
 
+# the pattern here is interpreted as "9+", not as "9\+"
+testing "sed special char as s/// delimiter, in pattern" \
+        "sed 's+9\++X+'" \
+        "X8=17\n" "" "9+8=17\n"
+
+# but in replacement string, "\&" remains "\&", not interpreted as "&"
+testing "sed special char as s/// delimiter, in replacement" \
+        "sed 's&9&X\&&'" \
+        "X&+8=17\n" "" "9+8=17\n"
+
 testing "sed /\$_in_regex/ should not match newlines, only end-of-line" \
         "sed ': testcont; /\\\\$/{ =; N; b testcont }'" \
         "\