[RFA] Emit a warning for ineffective set VAR = EXP command

[Doug Evans]

I think the convention now is to use prepare_for_testing to simplify a
lot of the setup in the .exp file.  Grep for other uses to see how
it's used.

On Wed, May 2, 2012 at 6:17 AM, Tristan Gingold <gingold@adacore.com> wrote:
>
> On Apr 27, 2012, at 6:04 PM, Tom Tromey wrote:
>
>>>>>>> "Tristan" == Tristan Gingold <gingold@adacore.com> writes:
>>
>> Tristan> I simply propose to emit a warning if the expression is not an
>> Tristan> assignment (or a comma expression).
>>
>> It seems reasonable to me.
>>
>> Tristan> Ok for trunk ?
>>
>> I think there should be a test case.
>
> Sure.  Is it ok with this testcase ?
>
> Tristan.
>
> gdb/testsuite/
> 2012-05-02  Tristan Gingold  <gingold@adacore.com>
>
>        * gdb.base/set-noassign.exp: New test.
>
> diff --git a/gdb/testsuite/gdb.base/set-noassign.exp b/gdb/testsuite/gdb.base/set-noassign.exp
> new file mode 100644
> index 0000000..d43bfbe
> --- /dev/null
> +++ b/gdb/testsuite/gdb.base/set-noassign.exp
> @@ -0,0 +1,41 @@
> +# Copyright 2012 Free Software Foundation, Inc.
> +
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +#
> +# This program is distributed in the hope that it will be useful,
> +# but WITHOUT ANY WARRANTY; without even the implied warranty of
> +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> +# GNU General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +
> +
> +set testfile start
> +set srcfile ${testfile}.c
> +set binfile ${objdir}/${subdir}/${testfile}
> +if  { [gdb_compile "${srcdir}/${subdir}/${srcfile}" "${binfile}" executable {debug}] != "" } {
> +    untested "Couldn't compile test program"
> +    return -1
> +}
> +
> +# Get things started.
> +
> +gdb_exit
> +gdb_start
> +gdb_reinitialize_dir $srcdir/$subdir
> +gdb_load ${binfile}
> +
> +if ![runto_main] then {
> +    fail "Can't run to main"
> +    return 0
> +}
> +
> +# Verify that set command without assignment emits a warning.
> +#
> +gdb_test "set x==3" \
> +       "warning: Expression is not an assignment \\(and might have no effect\\)" \
> +       "warning for set without assignment"
>