hush: fix some fallout from prev commits, add testsuite

3 files changed, 31 insertions, 12 deletions

diff --git a/shell/hush.c b/shell/hush.c
index ca854c2eb..603e19fe9 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -1234,11 +1234,14 @@ static void o_addqchr(o_string *o, int ch, int quote)
 static int o_save_ptr(o_string *o, int n)
 {
         char **list = (char**)o->data;
-        int string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
-        int string_len = o->length - string_start;
+        int string_start;
+        int string_len;
 
         if (!o->has_empty_slot) {
+                string_start = ((n + 0xf) & ~0xf) * sizeof(list[0]);
+                string_len = o->length - string_start;
                 if (!(n & 0xf)) { /* 0, 0x10, 0x20...? */
+                        //bb_error_msg("list[%d]=%d string_start=%d (growing)", n, string_len, string_start);
                         /* list[n] points to string_start, make space for 16 more pointers */
                         o->maxlen += 0x10 * sizeof(list[0]);
                         o->data = xrealloc(o->data, o->maxlen + 1);
@@ -1246,8 +1249,12 @@ static int o_save_ptr(o_string *o, int n)
                         memmove(list + n + 0x10, list + n, string_len);
                         o->length += 0x10 * sizeof(list[0]);
                 }
+                //else bb_error_msg("list[%d]=%d string_start=%d", n, string_len, string_start);
         } else {
                 /* We have empty slot at list[n], reuse without growth */
+                string_start = ((n+1 + 0xf) & ~0xf) * sizeof(list[0]); /* NB: n+1! */
+                string_len = o->length - string_start;
+                //bb_error_msg("list[%d]=%d string_start=%d (empty slot)", n, string_len, string_start);
                 o->has_empty_slot = 0;
         }
         list[n] = (char*)string_len;
@@ -2684,18 +2691,20 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
                 arg = ++p;
         } /* end of "while (SPECIAL_VAR_SYMBOL is found) ..." */
 
-        o_debug_list("expand_vars_to_list[a]", output, n);
-        o_addstr(output, arg, strlen(arg) + 1);
-        o_debug_list("expand_vars_to_list[b]", output, n);
-//TESTME
-        if (output->length - 1 == o_get_last_ptr(output, n)) { /* expansion is empty */
-                if (!(ored_ch & 0x80)) { /* all vars were not quoted... */
-                        n--;
-                        /* allow to reuse list[n] later without re-growth */
-                        output->has_empty_slot = 1;
+        {
+                int len = strlen(arg);
+                if (len) {
+                        o_debug_list("expand_vars_to_list[a]", output, n);
+                        o_addstr(output, arg, len + 1);
+                        o_debug_list("expand_vars_to_list[b]", output, n);
+                } else if (output->length == o_get_last_ptr(output, n)) { /* expansion is empty */
+                        if (!(ored_ch & 0x80)) { /* all vars were not quoted... */
+                                n--;
+                                /* allow to reuse list[n] later without re-growth */
+                                output->has_empty_slot = 1;
+                        }
                 }
         }
-
         return n;
 }
 
diff --git a/shell/hush_test/hush-vars/empty.right b/shell/hush_test/hush-vars/empty.right
new file mode 100644
index 000000000..2cb3c70f2
--- /dev/null
+++ b/shell/hush_test/hush-vars/empty.right
@@ -0,0 +1,3 @@
+a b c d e f 1 2 3 4 5 6 7 8 9 0 A B C D E F
+a b c d e f 1 2 3 4 5 6 7 8 9 0 A B C D E F
+a b c d e f 1 2 3 4 5 6 7 8 9 0 A B C D E F
diff --git a/shell/hush_test/hush-vars/empty.tests b/shell/hush_test/hush-vars/empty.tests
new file mode 100755
index 000000000..72ac2c743
--- /dev/null
+++ b/shell/hush_test/hush-vars/empty.tests
@@ -0,0 +1,7 @@
+#!/bin/sh
+
+e=
+
+echo a b c d e f 1 2 3 4 5 6 7 8 9 0 A B C D E F
+echo a $e b $e c $e d $e e $e f $e 1 $e 2 $e 3 $e 4 $e 5 $e 6 $e 7 $e 8 $e 9 $e 0 $e A $e B $e C $e D $e E $e F
+echo $e a $e b $e c $e d $e e $e f $e 1 $e 2 $e 3 $e 4 $e 5 $e 6 $e 7 $e 8 $e 9 $e 0 $e A $e B $e C $e D $e E $e F