Re: preventing the leading space in process substitution

[Peter Stephenson <pws@csr.com>]

On Thu, 11 Sep 2008 08:44:07 -0400
"Rocky Bernstein" <rocky.bernstein@gmail.com> wrote:
> A gentle nudge on having trap DEBUG (if not other traps as well) inherited
> in subshells. ;-)

They are currently reset explicitly.  I think for most traps that's to
avoid the subshell picking up a signal destined for the parent shell
(unless the trap has specifically been set in the subshell), but it's
possible Bart has detailed knowledge.

I can't see why we shouldn't keep the debug-related traps, ZERR and DEBUG,
alive in subshells.  It doesn't look like the behaviour was ever
documented.  Would anyone expect the current behaviour?  I hadn't realised
until you pointed it out.

Index: Doc/Zsh/builtins.yo
===================================================================
RCS file: /cvsroot/zsh/zsh/Doc/Zsh/builtins.yo,v
retrieving revision 1.112
diff -u -r1.112 builtins.yo
--- Doc/Zsh/builtins.yo	5 Sep 2008 09:05:22 -0000	1.112
+++ Doc/Zsh/builtins.yo	11 Sep 2008 13:01:02 -0000
@@ -1330,7 +1330,9 @@
 and the tt(trap) statement is not executed inside the body of a function,
 then the command var(arg) is executed when the shell terminates.
 
-tt(ZERR), tt(DEBUG), and tt(EXIT) traps are not executed inside other traps.
+tt(ZERR), tt(DEBUG), and tt(EXIT) traps are not executed inside other
+traps.  tt(ZERR) and tt(DEBUG) traps are kept within subshells, while
+other traps are reset.
 
 Note that traps defined with the tt(trap) builtin are slightly different
 from those defined as `tt(TRAP)var(NAL) () { ... }', as the latter have
Index: Src/exec.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/exec.c,v
retrieving revision 1.149
diff -u -r1.149 exec.c
--- Src/exec.c	10 Sep 2008 15:57:17 -0000	1.149
+++ Src/exec.c	11 Sep 2008 13:01:02 -0000
@@ -869,7 +869,8 @@
 
     if (!(flags & ESUB_KEEPTRAP))
 	for (sig = 0; sig < VSIGCOUNT; sig++)
-	    if (!(sigtrapped[sig] & ZSIG_FUNC))
+	    if (!(sigtrapped[sig] & ZSIG_FUNC) &&
+		sig != SIGDEBUG && sig != SIGZERR)
 		unsettrap(sig);
     monitor = isset(MONITOR);
     if (flags & ESUB_NOMONITOR)


-- 
Peter Stephenson <pws@csr.com>                  Software Engineer
CSR PLC, Churchill House, Cambridge Business Park, Cowley Road
Cambridge, CB4 0WZ, UK                          Tel: +44 (0)1223 692070