Re: RFA: add testsuite function for answering internal error questions

[Jim Blandy <jimb@redhat.com>]

Fernando Nasser <fnasser@redhat.com> writes:
> > The idea is excellent, we should have thought of this before.
> > I need you to make a couple of changes before checking it in, if you
> > don't mind:
> > 1)
> >            fail "$testname (internal error resync timeout)"
> > should actually be
> >            perror "Could not resync from internal error (timeout)"
> > It is a test harness failure if we were not able to resync and GDB
> > cannot be no lonmger used for testing.  This will properly make all
> > tests to be unresolved until gdb is restarted.
> > Note that I've also got ridden of the TESTNAME argument as well.
> > The test itself has been marked as failed already since an internal
> > error was raised.  We we fail to resynch we can just issue a
> > constant message like:
> > ERROR: Could not resync from internal error (timeout)

Okay, I've made that change.

> > 2) Please get rid of the global variable.  You can just do:
> >  > +          -re ".*A problem internal to GDB has been detected" {
> >  > +          # The pattern above must be set up to match the
> >  > +          # internal error message, but none of the questions
> >  > +         # that follow it
> >  > +              fail "$message"
> >  > +              gdb_internal_error_resync
> >  > +          }

The reason I put the global variable there is that people may want to
use gdb_internal_error_resync in their own gdb_expect constructs, when
they're not using gdb_test or gdb_test_multiple.  If GDB changes the
way it reports internal errors, the regexp will need to change, too,
so I thought it was worthwhile to define it in one place, and then
have everyone use it.  The comments for gdb_internal_error_resync
explain this.

Here's the patch, adapted to the current sources (esp. the
introduction of gdb_test_multiple):

2003-02-04  Jim Blandy  <jimb@redhat.com>

	* lib/gdb.exp (gdb_internal_error_regexp): New variable.
	(gdb_internal_error_resync): New procedure.
        (gdb_test_multiple): If the command results in an internal error,
        answer GDB's questions until we get back to a prompt.

Index: gdb/testsuite/lib/gdb.exp
===================================================================
RCS file: /cvs/src/src/gdb/testsuite/lib/gdb.exp,v
retrieving revision 1.34
diff -c -r1.34 gdb.exp
*** gdb/testsuite/lib/gdb.exp	31 Jan 2003 00:38:33 -0000	1.34
--- gdb/testsuite/lib/gdb.exp	4 Feb 2003 22:31:28 -0000
***************
*** 360,365 ****
--- 360,416 ----
  }
  
  
+ # A regular expression matching the output GDB produces when it
+ # reports an internal error.
+ set gdb_internal_error_regexp ".*A problem internal to GDB has been detected"
+ 
+ 
+ # gdb_internal_error_resync
+ #
+ # Answer the questions GDB asks after it reports an internal error
+ # until we get back to a GDB prompt.  Decline to quit the debugging
+ # session, and decline to create a core file.  If we're unable to
+ # resync, then report an error using 'perror', to abort the rest of
+ # the test script.
+ #
+ # This procedure just answers whatever questions come up until it sees
+ # a GDB prompt; it doesn't require you to have matched the input up to
+ # any specific point.  However, it only answers questions it sees in
+ # the output itself, so if you've matched a question, you had better
+ # answer it yourself before calling this.
+ #
+ # The variable `gdb_internal_error_regexp' is set up to match the
+ # internal error message, but none of the questions that follow it, so
+ # you can write code like this:
+ # 
+ # gdb_expect {
+ #     ...
+ #     -re $gdb_internal_error_regexp {
+ #         gdb_internal_error_resync "$message (internal error)"
+ #     }
+ #     ...
+ # }
+ proc gdb_internal_error_resync {} {
+     global gdb_prompt
+ 
+     gdb_expect {
+         -re "Quit this debugging session\\? \\(y or n\\) $" {
+             send_gdb "n\n"
+             exp_continue
+         }
+         -re "Create a core file of GDB\\? \\(y or n\\) $" {
+             send_gdb "n\n"
+             exp_continue
+         }
+         -re "$gdb_prompt $" {
+             # We're resynchronized.
+         }
+         timeout {
+             perror "Could not resync from internal error (timeout)"
+         }
+     }
+ }
+   
  
  # gdb_test_multiple COMMAND MESSAGE EXPECT_ARGUMENTS
  # Send a command to gdb; test the result.
***************
*** 383,388 ****
--- 434,440 ----
      global verbose
      global gdb_prompt
      global GDB
+     global gdb_internal_error_regexp
      upvar timeout timeout
  
      if { $message == "" } {
***************
*** 511,516 ****
--- 563,572 ----
      }
  
      set code {
+          -re $gdb_internal_error_regexp {
+              fail "$message (GDB internal error)"
+              gdb_internal_error_resync
+          }
  	 -re "\\*\\*\\* DOSEXIT code.*" {
  	     if { $message != "" } {
  		 fail "$message";