Bug#315444: test case

[Colin Watson <cjwatson@debian.org>]

On Wed, Jun 22, 2005 at 02:15:22PM -0400, Joey Hess wrote:
> joey@dragon:~>cat test
> set -e
> eval false || true
> exit 0
> joey@dragon:~>busybox sh test
> zsh: exit 1     busybox sh test
> joey@dragon:~>sh test
> joey@dragon:~>dash test
> joey@dragon:~>bash test
> joey@dragon:~>zsh test   
> joey@dragon:~>
> 
> Workarond is to enclose the eval statement in parens, so this will work in
> debootstrap:
> 
>     (eval $(eval echo \${EXIT_THING_$n})) 2>/dev/null || true
> 
> Cloning the bug to busybox, I'm using 1.00 in the test above, though
> busybox-cvs must also have the bug.

This is a rather hacky patch against busybox-cvs (but should apply to
busybox without too much trouble) for this.

Unfortunately I had to take the approach of avoiding throwing the
exception in the first place, necessitating a static variable, rather
than catching the exception in evalbltin() if flags & EV_TESTED, which I
think would have been much neater. However, when I tried to take the
latter approach, I apparently didn't manage to restore all the
pre-exception state properly or something, because immediately after
evaluating 'eval false || true' the (interactive) shell decided it had
hit EOF on input and exited. Somebody who understands busybox ash better
might want to look into this.

I also haven't run this through a shell test suite to make sure I didn't
break anything else. That really needs to happen before applying this to
the Debian package.

diff -u busybox-cvs-20040623/shell/ash.c busybox-cvs-20040623/shell/ash.c
--- busybox-cvs-20040623/shell/ash.c
+++ busybox-cvs-20040623/shell/ash.c
@@ -1218,7 +1218,7 @@
 
 
 
-static void evalstring(char *);
+static void evalstring(char *, int);
 union node;     /* BLETCH for ansi C */
 static void evaltree(union node *, int);
 static void evalbackcmd(union node *, struct backcmd *);
@@ -1229,6 +1229,8 @@
 static int skipcount;           /* number of levels to skip */
 static int funcnest;                   /* depth of function calls */
 
+static int bltintested = 0;     /* builtin command tested; appease set -e */
+
 /* reasons for skipping commands (see comment on breakcmd routine) */
 #define SKIPBREAK       1
 #define SKIPCONT        2
@@ -2692,7 +2694,7 @@
 static void expredir(union node *);
 static void evalpipe(union node *, int);
 static void evalcommand(union node *, int);
-static int evalbltin(const struct builtincmd *, int, char **);
+static int evalbltin(const struct builtincmd *, int, char **, int);
 static int evalfun(struct funcnode *, int, char **, int);
 static void prehash(union node *);
 static int bltincmd(int, char **);
@@ -2732,7 +2734,7 @@
 			STPUTC('\0', concat);
 			p = grabstackstr(concat);
 		}
-		evalstring(p);
+		evalstring(p, bltintested ? EV_TESTED : 0);
 	}
 	return exitstatus;
 }
@@ -2743,7 +2745,7 @@
  */
 
 static void
-evalstring(char *s)
+evalstring(char *s, int flags)
 {
 	union node *n;
 	struct stackmark smark;
@@ -2752,7 +2754,7 @@
 	setinputstring(s);
 
 	while ((n = parsecmd(0)) != NEOF) {
-		evaltree(n, 0);
+		evaltree(n, flags);
 		popstackmark(&smark);
 		if (evalskip)
 			break;
@@ -3387,7 +3389,7 @@
 			}
 			listsetvar(list, i);
 		}
-		if (evalbltin(cmdentry.u.cmd, argc, argv)) {
+		if (evalbltin(cmdentry.u.cmd, argc, argv, flags)) {
 			int exit_status;
 			int i, j;
 
@@ -3432,9 +3434,10 @@
 }
 
 static int
-evalbltin(const struct builtincmd *cmd, int argc, char **argv) {
+evalbltin(const struct builtincmd *cmd, int argc, char **argv, int flags) {
 	char *volatile savecmdname;
 	struct jmploc *volatile savehandler;
+	volatile int savebltintested;
 	struct jmploc jmploc;
 	int i;
 
@@ -3446,10 +3449,14 @@
 	commandname = argv[0];
 	argptr = argv + 1;
 	optptr = NULL;                  /* initialize nextopt */
+	savebltintested = bltintested;
+	if (flags & EV_TESTED)
+		bltintested = 1;
 	exitstatus = (*cmd->builtin)(argc, argv);
 	flushall();
 cmddone:
 	exitstatus |= ferror(stdout);
+	bltintested = savebltintested;
 	commandname = savecmdname;
 	exsig = 0;
 	handler = savehandler;
@@ -7966,7 +7973,7 @@
 state3:
 	state = 4;
 	if (minusc)
-		evalstring(minusc);
+		evalstring(minusc, 0);
 
 	if (sflag || minusc == NULL) {
 #ifdef CONFIG_FEATURE_COMMAND_SAVEHISTORY
@@ -11817,7 +11824,7 @@
 		p = trap[p - q + 1];
 		if (!p)
 			continue;
-		evalstring(p);
+		evalstring(p, 0);
 		exitstatus = savestatus;
 	}
 }
@@ -11910,7 +11917,7 @@
 	handler = &loc;
 	if ((p = trap[0]) != NULL && *p != '\0') {
 		trap[0] = NULL;
-		evalstring(p);
+		evalstring(p, 0);
 	}
 	flushall();
 #ifdef CONFIG_FEATURE_COMMAND_SAVEHISTORY

-- 
Colin Watson                                       [cjwatson@debian.org]