Re: Help me track down a tough bug? (probably funcfiletrace, subshells and possibly I/O redirection)

[Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>]

On Sun, 28 Sep 2008 15:19:37 -0400
"Rocky Bernstein" <rocky.bernstein@xxxxxxxxx> wrote:
> There is what looks to me a bug in the recent funcfiletrace that I've
> been trying to isolate.
> 
> #!/usr/local/bin/zsh
> # Test debugger handling of subshells
> (
>     x=$(print 5; print 6)
> )
> (/tmp/zshdb/testing.sh:1):
> print 5                            # In a 2nd subshell, backtick
> zshdb<((7))> where                 # ((..)) indicates this.
>
> What's wrong is that we aren't on line 1 of testing.sh.

exec.c:parse_string() resets the line number for every invocation.
That's fine for eval, where we've fixed this up explicitly, but doesn't
work in the call from exec.c:getoutput() which is the case here.
Obviously that's not consistent with the fact that it doesn't have its
own file; we don't do the special eval handling of reconstructing the
file location in this case.

The reason (...) is different is it's parsed straight away when the
shell reads it in; it's not stored as a string argument to be looked at
again later.

It's possible we can simply get away with not resetting the line number
in any case without its own entry on the function stack.  That's about
the simplest fix, but changes the meaning of line numbers in all string
evaluations apart from eval, trap and functions, where we have the
special handling.  I'm coming round to the view that this is nonetheless
the best way of salvaging consistency of the debugging environment.
Have a go at this and see if it looks sensible.

Index: Src/builtin.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/builtin.c,v
retrieving revision 1.209
diff -u -r1.209 builtin.c
--- Src/builtin.c	27 Sep 2008 19:57:33 -0000	1.209
+++ Src/builtin.c	28 Sep 2008 21:11:21 -0000
@@ -4781,7 +4781,7 @@
     } else
 	fpushed = 0;
 
-    prog = parse_string(zjoin(argv, ' ', 1));
+    prog = parse_string(zjoin(argv, ' ', 1), 1);
     if (prog) {
 	if (wc_code(*prog->prog) != WC_LIST) {
 	    /* No code to execute */
@@ -5781,7 +5781,7 @@
     arg = *argv++;
     if (!*arg)
 	prog = &dummy_eprog;
-    else if (!(prog = parse_string(arg))) {
+    else if (!(prog = parse_string(arg, 1))) {
 	zwarnnam(name, "couldn't parse trap command");
 	return 1;
     }
Index: Src/exec.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/exec.c,v
retrieving revision 1.156
diff -u -r1.156 exec.c
--- Src/exec.c	26 Sep 2008 09:11:29 -0000	1.156
+++ Src/exec.c	28 Sep 2008 21:11:22 -0000
@@ -188,17 +188,21 @@
 
 /**/
 mod_export Eprog
-parse_string(char *s)
+parse_string(char *s, int reset_lineno)
 {
     Eprog p;
-    zlong oldlineno = lineno;
+    zlong oldlineno;
 
     lexsave();
     inpush(s, INP_LINENO, NULL);
     strinbeg(0);
-    lineno = 1;
+    if (reset_lineno) {
+	oldlineno = lineno;
+	lineno = 1;
+    }
     p = parse_list();
-    lineno = oldlineno;
+    if (reset_lineno)
+	lineno = oldlineno;
     if (tok == LEXERR && !lastval)
 	lastval = 1;
     strinend();
@@ -954,7 +958,7 @@
     Eprog prog;
 
     pushheap();
-    if ((prog = parse_string(s)))
+    if ((prog = parse_string(s, 0)))
 	execode(prog, dont_change_job, exiting);
     popheap();
 }
@@ -3445,7 +3449,7 @@
     pid_t pid;
     char *s;
 
-    if (!(prog = parse_string(cmd)))
+    if (!(prog = parse_string(cmd, 0)))
 	return NULL;
 
     if ((s = simple_redir_name(prog, REDIR_READ))) {
@@ -3566,7 +3570,7 @@
 	return NULL;
     }
     *str = '\0';
-    if (str[1] || !(prog = parse_string(cmd + 2))) {
+    if (str[1] || !(prog = parse_string(cmd + 2, 0))) {
 	zerr("parse error in process substitution");
 	return NULL;
     }
@@ -4453,7 +4457,7 @@
 		    d = metafy(d, rlen, META_REALLOC);
 
 		    scriptname = dupstring(s);
-		    r = parse_string(d);
+		    r = parse_string(d, 1);
 		    scriptname = oldscriptname;
 
 		    if (fname)
Index: Src/glob.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/glob.c,v
retrieving revision 1.65
diff -u -r1.65 glob.c
--- Src/glob.c	11 May 2008 19:55:21 -0000	1.65
+++ Src/glob.c	28 Sep 2008 21:11:23 -0000
@@ -3329,7 +3329,7 @@
 {
     Eprog prog;
 
-    if ((prog = parse_string(str))) {
+    if ((prog = parse_string(str, 0))) {
 	int ef = errflag, lv = lastval, ret;
 
 	unsetparam("reply");
Index: Src/parse.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/parse.c,v
retrieving revision 1.75
diff -u -r1.75 parse.c
--- Src/parse.c	24 Sep 2008 19:19:56 -0000	1.75
+++ Src/parse.c	28 Sep 2008 21:11:24 -0000
@@ -2831,7 +2831,7 @@
 	close(fd);
 	file = metafy(file, flen, META_REALLOC);
 
-	if (!(prog = parse_string(file)) || errflag) {
+	if (!(prog = parse_string(file, 1)) || errflag) {
 	    errflag = 0;
 	    close(dfd);
 	    zfree(file, flen);
Index: Src/Modules/parameter.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/Modules/parameter.c,v
retrieving revision 1.49
diff -u -r1.49 parameter.c
--- Src/Modules/parameter.c	11 Sep 2008 17:14:39 -0000	1.49
+++ Src/Modules/parameter.c	28 Sep 2008 21:11:24 -0000
@@ -279,7 +279,7 @@
 
     val = metafy(val, strlen(val), META_REALLOC);
 
-    prog = parse_string(val);
+    prog = parse_string(val, 1);
 
     if (!prog || prog == &dummy_eprog) {
 	zwarn("invalid function definition", value);
Index: Src/Modules/zpty.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/Modules/zpty.c,v
retrieving revision 1.38
diff -u -r1.38 zpty.c
--- Src/Modules/zpty.c	15 May 2008 15:51:01 -0000	1.38
+++ Src/Modules/zpty.c	28 Sep 2008 21:11:24 -0000
@@ -299,7 +299,7 @@
     if (!ineval)
 	scriptname = "(zpty)";
 
-    prog = parse_string(zjoin(args, ' ', 1));
+    prog = parse_string(zjoin(args, ' ', 1), 0);
     if (!prog) {
 	errflag = 0;
 	scriptname = oscriptname;
Index: Src/Modules/zutil.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/Modules/zutil.c,v
retrieving revision 1.23
diff -u -r1.23 zutil.c
--- Src/Modules/zutil.c	6 Jul 2007 21:52:40 -0000	1.23
+++ Src/Modules/zutil.c	28 Sep 2008 21:11:25 -0000
@@ -251,7 +251,7 @@
     if (eval) {
 	int ef = errflag;
 
-	eprog = parse_string(zjoin(vals, ' ', 1));
+	eprog = parse_string(zjoin(vals, ' ', 1), 0);
 	errflag = ef;
 
 	if (!eprog)


-- 
Peter Stephenson <p.w.stephenson@xxxxxxxxxxxx>
Web page now at http://homepage.ntlworld.com/p.w.stephenson/