3 files changed, 36 insertions, 6 deletions

diff --git a/shell/hush.c b/shell/hush.c
index 5b5a54241..2c1d31c6d 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -2380,7 +2380,10 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
                 p = strchr(p, SPECIAL_VAR_SYMBOL);
 
                 first_ch = arg[0] | or_mask; /* forced to "quoted" if or_mask = 0x80 */
-                ored_ch |= first_ch;
+                /* "$@" is special. Even if quoted, it can still
+                 * expand to nothing (not even an empty string) */
+                if ((first_ch & 0x7f) != '@')
+                        ored_ch |= first_ch;
                 val = NULL;
                 switch (first_ch & 0x7f) {
                 /* Highest bit in first_ch indicates that var is double-quoted */
@@ -2401,6 +2404,7 @@ static int expand_vars_to_list(o_string *output, int n, char *arg, char or_mask)
                         i = 1;
                         if (!global_argv[i])
                                 break;
+                        ored_ch |= first_ch; /* do it for "$@" _now_, when we know it's not empty */
                         if (!(first_ch & 0x80)) { /* unquoted $* or $@ */
                                 smallint sv = output->o_quote;
                                 /* unquoted var's contents should be globbed, so don't quote */
@@ -2932,15 +2936,25 @@ static int done_word(o_string *word, struct p_context *ctx)
                         }
                 }
 #endif
-                if (word->nonnull /* we saw "xx" or 'xx' */
+                if (word->nonnull /* word had "xx" or 'xx' at least as part of it */
                  /* optimization: and if it's ("" or '') or ($v... or `cmd`...): */
                  && (word->data[0] == '\0' || word->data[0] == SPECIAL_VAR_SYMBOL)
                  /* (otherwise it's "abc".... and is already safe) */
                 ) {
-                        /* Insert "empty variable" reference, this makes
-                         * e.g. "", $empty"" etc to not disappear */
-                        o_addchr(word, SPECIAL_VAR_SYMBOL);
-                        o_addchr(word, SPECIAL_VAR_SYMBOL);
+                        /* but exclude "$@"! it expands to no word despite "" */
+                        char *p = word->data;
+                        while (p[0] == SPECIAL_VAR_SYMBOL
+                            && (p[1] & 0x7f) == '@'
+                            && p[2] == SPECIAL_VAR_SYMBOL
+                        ) {
+                                p += 3;
+                        }
+                        if (p == word->data || p[0] != '\0') {
+                                /* Insert "empty variable" reference, this makes
+                                 * e.g. "", $empty"" etc to not disappear */
+                                o_addchr(word, SPECIAL_VAR_SYMBOL);
+                                o_addchr(word, SPECIAL_VAR_SYMBOL);
+                        }
                 }
                 child->argv = add_malloced_string_to_strings(child->argv, xstrdup(word->data));
                 debug_print_strings("word appended to argv", child->argv);
diff --git a/shell/hush_test/hush-parsing/starquoted2.right b/shell/hush_test/hush-parsing/starquoted2.right
new file mode 100644
index 000000000..46f24369e
--- /dev/null
+++ b/shell/hush_test/hush-parsing/starquoted2.right
@@ -0,0 +1,2 @@
+Should be printed
+Should be printed
diff --git a/shell/hush_test/hush-parsing/starquoted2.tests b/shell/hush_test/hush-parsing/starquoted2.tests
new file mode 100755
index 000000000..782d71b88
--- /dev/null
+++ b/shell/hush_test/hush-parsing/starquoted2.tests
@@ -0,0 +1,14 @@
+if test $# != 0; then
+    exec "$THIS_SH" "$0"
+fi
+
+# No params!
+for a in "$*"; do echo Should be printed; done
+for a in "$@"; do echo Should not be printed; done
+# Yes, believe it or not, bash is mesmerized by "$@" and stops
+# treating "" as "this word cannot be expanded to nothing,
+# but must be at least null string". Now it can be expanded to nothing.
+for a in "$@"""; do echo Should not be printed; done
+for a in """$@"; do echo Should not be printed; done
+for a in """$@"''"$@"''; do echo Should not be printed; done
+for a in ""; do echo Should be printed; done