ash: remove parsebackquote flag

Commit 503a0b8 from git://git.kernel.org/pub/scm/utils/dash/dash.git
by Herbert Xu says:

  >The parsebackquote flag is only used in a test where it always has the
  >value zero.  So we can remove it altogether.

The first statement is incorrect:  parsebackquote is non-zero when
backquotes (as opposed to $(...)) are used for command substitution.
It is possible for the test to be executed with parsebackquote != 0 in
that case.

The test is question checks whether quotes have been closed, raising
the error "unterminated quoted string" if they haven't.  There seems
to be no good reason to allow unclosed quotes within backquotes.  Bash,
hush and dash (after commit 503a0b8) all treat the following as an error:

   XX=`"pwd`

whereas BusyBox ash doesn't.  It just ignores the unclosed quote and
executes pwd.

So, parsebackquote should be removed but not for the reason stated.

function                                             old     new   delta
parsebackquote                                         1       -      -1
readtoken1                                          3222    3182     -40
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 0/1 up/down: 0/-41)             Total: -41 bytes

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

3 files changed, 3 insertions, 7 deletions

diff --git a/shell/ash.c b/shell/ash.c
index 4c01e67..6627cec 100644
--- a/shell/ash.c
+++ b/shell/ash.c
@@ -10473,7 +10473,6 @@ struct heredoc {
 };
 
 static smallint tokpushback;           /* last token pushed back */
-static smallint parsebackquote;        /* nonzero if we are inside backquotes */
 static smallint quoteflag;             /* set if (part of) last token was quoted */
 static token_id_t lasttoken;           /* last token read (integer id Txxx) */
 static struct heredoc *heredoclist;    /* list of here documents to read */
@@ -11313,7 +11312,7 @@ readtoken1(int c, int syntax, char *eofmark, int striptabs)
 	if (syntax == ARISYNTAX)
 		raise_error_syntax("missing '))'");
 #endif
-	if (syntax != BASESYNTAX && !parsebackquote && eofmark == NULL)
+	if (syntax != BASESYNTAX && eofmark == NULL)
 		raise_error_syntax("unterminated quoted string");
 	if (varnest != 0) {
 		startlinno = g_parsefile->linno;
@@ -11609,7 +11608,6 @@ parsesub: {
  */
 parsebackq: {
 	struct nodelist **nlpp;
-	smallint savepbq;
 	union node *n;
 	char *volatile str;
 	struct jmploc jmploc;
@@ -11620,10 +11618,8 @@ parsebackq: {
 #ifdef __GNUC__
 	(void) &saveprompt;
 #endif
-	savepbq = parsebackquote;
 	if (setjmp(jmploc.loc)) {
 		free(str);
-		parsebackquote = 0;
 		exception_handler = savehandler;
 		longjmp(exception_handler->loc, 1);
 	}
@@ -11707,7 +11703,6 @@ parsebackq: {
 		nlpp = &(*nlpp)->next;
 	*nlpp = stzalloc(sizeof(**nlpp));
 	/* (*nlpp)->next = NULL; - stzalloc did it */
-	parsebackquote = oldstyle;
 
 	if (oldstyle) {
 		saveprompt = doprompt;
@@ -11741,7 +11736,6 @@ parsebackq: {
 		str = NULL;
 		INT_ON;
 	}
-	parsebackquote = savepbq;
 	exception_handler = savehandler;
 	USTPUTC(CTLBACKQ, out);
 	if (oldstyle)
diff --git a/shell/ash_test/ash-misc/tickquote1.right b/shell/ash_test/ash-misc/tickquote1.right
new file mode 100644
index 0000000..2e661bf
--- /dev/null
+++ b/shell/ash_test/ash-misc/tickquote1.right
@@ -0,0 +1 @@
+./tickquote1.tests: line 1: syntax error: unterminated quoted string
diff --git a/shell/ash_test/ash-misc/tickquote1.tests b/shell/ash_test/ash-misc/tickquote1.tests
new file mode 100755
index 0000000..90d5bbc
--- /dev/null
+++ b/shell/ash_test/ash-misc/tickquote1.tests
@@ -0,0 +1 @@
+echo `"pwd`