[PATCH] Make enable reset disposition

[Stan Shebs <stanshebs at earthlink dot net>]

In the process of developing an additional enablement option (to be 
posted soon), I ran across this little bit of behavior that seems wrong; 
if you do "enable once" and then "enable" on a breakpoint, the 
disposition is unchanged - the breakpoint is still going to get disabled 
after being hit.  (Similarly for "enable delete" breakpoints.)

While one could argue that this is good, because you can toggle a 
breakpoint's enablement independently of its ultimate disposition, the 
downside is that you're stuck with your original choice; once you've set 
a breakpoint's disposition to delete for instance, there is no way to 
undo that, and when the breakpoint is hit, it's gone, conditions and 
command list and all.

Having "enable" reset dispositions has its own fault, namely that if you 
do just "enable" to enable all breakpoints, and they have different 
dispositions, then all the dispositions are reset en masse, and you 
would have to manually do a combination of "enable once", "enable 
delete", etc to get those back to desired values.

A more complicated solution might be to introduce an additional flavor 
or option of enable command ("enable always"?), but I wouldn't like to 
try to explain the different flavors to users, and chances are that 
nobody would remember it anyway.

I couldn't see anything in the manual that addressed the point either way.

Stan

2012-01-26  Stan Shebs <stan@codesourcery.com>

    * breakpoint.c (enable_breakpoint): Set disposition instead
    of copying it.

    * gdb.base/ena-dis-br.exp: Add a check of disposition reset.


Index: breakpoint.c
===================================================================
RCS file: /cvs/src/src/gdb/breakpoint.c,v
retrieving revision 1.648
diff -u -p -r1.648 breakpoint.c
--- breakpoint.c    25 Jan 2012 15:57:04 -0000    1.648
+++ breakpoint.c    26 Jan 2012 23:42:32 -0000
@@ -12945,7 +12945,7 @@ enable_breakpoint_disp (struct breakpoin
 void
 enable_breakpoint (struct breakpoint *bpt)
 {
-  enable_breakpoint_disp (bpt, bpt->disposition);
+  enable_breakpoint_disp (bpt, disp_donttouch);
 }

 static void
Index: testsuite/gdb.base/ena-dis-br.exp
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/gdb.base/ena-dis-br.exp,v
retrieving revision 1.19
diff -u -p -r1.19 ena-dis-br.exp
--- testsuite/gdb.base/ena-dis-br.exp    16 Jan 2012 16:21:44 -0000    1.19
+++ testsuite/gdb.base/ena-dis-br.exp    26 Jan 2012 23:42:32 -0000
@@ -78,6 +78,9 @@ proc break_at { breakpoint where } {

 set bp [break_at "marker1" " line ($bp_location15|$bp_location16)"]

+# Do this first to check that regular enable resets the disposition.
+gdb_test_no_output "enable once $bp" "enable once break marker1"
+
 gdb_test_no_output "enable $bp" "enable break marker1"

 gdb_test "info break $bp" \