ash: do not expand tilde in parameter expansion within quotes

Test case:
   unset a
   echo "${a:-~root}"
Old result:
   /root
New result:
   ~root

Based on commit 170f44d from git://git.kernel.org/pub/scm/utils/dash/dash.git
by Herbert Xu

function                                             old     new   delta
evalvar                                              598     604      +6
parse_command                                       1440    1443      +3
localcmd                                             325     327      +2
readtoken1                                          3199    3200      +1
argstr                                              1180    1164     -16
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/1 up/down: 12/-16)             Total: -4 bytes

Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

3 files changed, 6 insertions, 5 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 4c43f1f30..d87166c4f 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -5529,7 +5529,7 @@ ash_arith(const char *s)
 #define EXP_RECORD      0x20    /* need to record arguments for ifs breakup */
 #define EXP_VARTILDE2   0x40    /* expand tildes after colons only */
 #define EXP_WORD        0x80    /* expand word in parameter expansion */
-#define EXP_QWORD       0x100   /* expand word in quoted parameter expansion */
+#define EXP_QUOTED      0x100   /* expand word in double quotes */
 /*
  * rmescape() flags
  */
@@ -6054,7 +6054,7 @@ argstr(char *p, int flags, struct strlist *var_str_list)
         };
         const char *reject = spclchars;
         int quotes = flags & QUOTES_ESC;
-        int breakall = flags & EXP_WORD;
+        int breakall = (flags & (EXP_WORD | EXP_QUOTED)) == EXP_WORD;
         int inquotes;
         size_t length;
         int startloc;
@@ -6072,8 +6072,6 @@ argstr(char *p, int flags, struct strlist *var_str_list)
                 flags &= ~EXP_TILDE;
  tilde:
                 q = p;
-                if ((unsigned char)*q == CTLESC && (flags & EXP_QWORD))
-                        q++;
                 if (*q == '~')
                         p = exptilde(p, q, flags);
         }
@@ -6790,7 +6788,7 @@ evalvar(char *p, int flags, struct strlist *var_str_list)
                 if (varlen < 0) {
                         argstr(
                                 p,
-                                flags | (quoted ? EXP_TILDE|EXP_QWORD : EXP_TILDE|EXP_WORD),
+                                flags | EXP_TILDE | EXP_WORD | (quoted ? EXP_QUOTED : 0),
                                 var_str_list
                         );
                         goto end;
diff --git a/shell/ash_test/ash-vars/var-do-not-expand-tilde-in-parameter-expansion-in-quotes.right b/shell/ash_test/ash-vars/var-do-not-expand-tilde-in-parameter-expansion-in-quotes.right
new file mode 100644
index 000000000..4b9b4f038
--- /dev/null
+++ b/shell/ash_test/ash-vars/var-do-not-expand-tilde-in-parameter-expansion-in-quotes.right
@@ -0,0 +1 @@
+~root
diff --git a/shell/ash_test/ash-vars/var-do-not-expand-tilde-in-parameter-expansion-in-quotes.tests b/shell/ash_test/ash-vars/var-do-not-expand-tilde-in-parameter-expansion-in-quotes.tests
new file mode 100755
index 000000000..d8eb8fc1b
--- /dev/null
+++ b/shell/ash_test/ash-vars/var-do-not-expand-tilde-in-parameter-expansion-in-quotes.tests
@@ -0,0 +1,2 @@
+unset a
+echo "${a:-~root}"