ash: add comment explaining last change

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/shell/ash.c b/shell/ash.c
index 5381f34eb1c67c5f04a50eab1b5682258be85c56..83a8e77f9d661eba25cd0e46c2355003fdf7caf5 100644 (file)
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -6756,6 +6756,10 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
        //              p, varname, strloc, subtype, startloc, varflags, quotes);
 
 #if BASH_PATTERN_SUBST
+       /* For "${v/pattern/repl}", we must find the delimiter _before_
+        * argstr() call expands possible variable references in pattern:
+        * think about "v=a; a=a/; echo ${v/$a/r}" case.
+        */
        repl = NULL;
        if (subtype == VSREPLACE || subtype == VSREPLACEALL) {
                /* Find '/' and replace with NUL */
@@ -6770,11 +6774,8 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
                                *repl = '\0';
                                break;
                        }
-                       if ((unsigned char)*repl == CTLESC
-                        && repl[1]
-                       ) {
+                       if ((unsigned char)*repl == CTLESC && repl[1])
                                repl++;
-                       }
                        repl++;
                }
        }
@@ -6941,11 +6942,10 @@ subevalvar(char *p, char *varname, int strloc, int subtype,
 
                if (!repl) {
                        //bb_error_msg("str9:'%s' slash_pos:%d", str, slash_pos);
+                       repl = nullstr;
                        if (slash_pos >= 0) {
                                repl = str + slash_pos;
                                *repl++ = '\0';
-                       } else {
-                               repl = nullstr;
                        }
                }
                //bb_error_msg("str:'%s' repl:'%s'", str, repl);