Add "undefined-command" error code at end of ^error result...

... when trying to execute an undefined GDB/MI command. When trying
to execute a GDB/MI command which does not exist, the current error
result record looks like this:

    -unsupported
    ^error,msg="Undefined MI command: unsupported"

The only indication that the command does not exist is the error
message. It would be a little fragile for a consumer to rely solely
on the contents of the error message in order to determine whether
a command exists or not.

This patch improves the situation by adding concept of error
code, starting with one well-defined error code ("undefined-command")
identifying errors due to a non-existant command. Here is the new
output:

    -unsupported
    ^error,msg="Undefined MI command: unsupported",code="undefined-command"

This error code is only displayed when the corresponding error
condition is met. Otherwise, the error record remains unchanged.
For instance:

    -symbol-list-lines foo.adb
    ^error,msg="-symbol-list-lines: Unknown source file name."

For frontends to be able to know whether they can rely on this
variable, a new entry "undefined-command-error-code" has been
added to the "-list-features" command.  Another option would be
to always generate an error="..." variable (for the default case,
we could decide for instance that the error code is the empty string).
But it seems more efficient to provide that info in "-list-features"
and then only add the error code when meaningful.

gdb/ChangeLog:

        (from Pedro Alves  <palves@redhat.com>)
        (from Joel Brobecker  <brobecker@adacore.com>)
        * exceptions.h (enum_errors) <UNDEFINED_COMMAND_ERROR>: New enum.
        * mi/mi-parse.c (mi_parse): Throw UNDEFINED_COMMAND_ERROR instead
        of a regular error when the GDB/MI command does not exist.
        * mi/mi-main.c (mi_cmd_list_features): Add
        "undefined-command-error-code".
        (mi_print_exception): Print an "undefined-command"
        error code if EXCEPTION.ERROR is UNDEFINED_COMMAND_ERROR.
        * NEWS: Add entry documenting the new "code" variable in
        "^error" result records.

gdb/doc/ChangeLog:

        * gdb.texinfo (GDB/MI Result Records): Fix the syntax of the
        "^error" result record concerning the error message.  Document
        the error code that may also be part of that result record.
        (GDB/MI Miscellaneous Commands): Document the
        "undefined-command-error-code" element in the output of
        the "-list-features" GDB/MI command.

gdb/testsuite/ChangeLog:

        * gdb.mi/mi-undefined-cmd.exp: New testcase.
This commit is contained in:
Joel Brobecker 2013-11-18 16:55:16 +04:00
parent 6b7cbff192
commit 2ea126fa78
9 changed files with 97 additions and 5 deletions

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@ -1,3 +1,16 @@
2013-12-03 Pedro Alves <palves@redhat.com>
Joel Brobecker <brobecker@adacore.com>
* exceptions.h (enum_errors) <UNDEFINED_COMMAND_ERROR>: New enum.
* mi/mi-parse.c (mi_parse): Throw UNDEFINED_COMMAND_ERROR instead
of a regular error when the GDB/MI command does not exist.
* mi/mi-main.c (mi_cmd_list_features): Add
"undefined-command-error-code".
(mi_print_exception): Print an "undefined-command"
error code if EXCEPTION.ERROR is UNDEFINED_COMMAND_ERROR.
* NEWS: Add entry documenting the new "code" variable in
"^error" result records.
2013-12-03 Joel Brobecker <brobecker@adacore.com>
* mi/mi-cmds.h (mi_cmd_info_gdb_mi_command): Declare.

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@ -161,6 +161,12 @@ show code-cache
** The new command -info-gdb-mi-command allows the user to determine
whether a GDB/MI command is supported or not.
** The "^error" result record returned when trying to execute an undefined
GDB/MI command now provides a variable named "code" whose content is the
"undefined-command" error code. Support for this feature can be verified
by using the "-list-features" command, which should contain
"undefined-command-error-code".
** The -trace-save MI command can optionally save trace buffer in Common
Trace Format now.

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@ -1,3 +1,12 @@
2013-12-03 Joel Brobecker <brobecker@adacore.com>
* gdb.texinfo (GDB/MI Result Records): Fix the syntax of the
"^error" result record concerning the error message. Document
the error code that may also be part of that result record.
(GDB/MI Miscellaneous Commands): Document the
"undefined-command-error-code" element in the output of
the "-list-features" GDB/MI command.
2013-12-03 Joel Brobecker <brobecker@adacore.com>
* gdb.texinfo (GDB/MI Miscellaneous Commands): Document

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@ -29333,10 +29333,19 @@ which threads are resumed.
@findex ^connected
@value{GDBN} has connected to a remote target.
@item "^error" "," @var{c-string}
@item "^error" "," "msg=" @var{c-string} [ "," "code=" @var{c-string} ]
@findex ^error
The operation failed. The @code{@var{c-string}} contains the corresponding
error message.
The operation failed. The @code{msg=@var{c-string}} variable contains
the corresponding error message.
If present, the @code{code=@var{c-string}} variable provides an error
code on which consumers can rely on to detect the corresponding
error condition. At present, only one error code is defined:
@table @samp
@item "undefined-command"
Indicates that the command causing the error does not exist.
@end table
@item "^exit"
@findex ^exit
@ -35204,6 +35213,10 @@ Indicates that all @sc{gdb/mi} commands accept the @option{--language}
option (@pxref{Context management}).
@item info-gdb-mi-command
Indicates support for the @code{-info-gdb-mi-command} command.
@item undefined-command-error-code
Indicates support for the "undefined-command" error code in error result
records, produced when trying to execute an undefined @sc{gdb/mi} command
(@pxref{GDB/MI Result Records}).
@end table
@subheading The @code{-list-target-features} Command

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@ -93,6 +93,9 @@ enum errors {
aborted as the inferior state is no longer valid. */
TARGET_CLOSE_ERROR,
/* An undefined command was executed. */
UNDEFINED_COMMAND_ERROR,
/* Add more errors here. */
NR_ERRORS
};

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@ -1818,6 +1818,7 @@ mi_cmd_list_features (char *command, char **argv, int argc)
ui_out_field_string (uiout, NULL, "ada-exceptions");
ui_out_field_string (uiout, NULL, "language-option");
ui_out_field_string (uiout, NULL, "info-gdb-mi-command");
ui_out_field_string (uiout, NULL, "undefined-command-error-code");
#if HAVE_PYTHON
if (gdb_python_initialized)
@ -2023,7 +2024,16 @@ mi_print_exception (const char *token, struct gdb_exception exception)
fputs_unfiltered ("unknown error", raw_stdout);
else
fputstr_unfiltered (exception.message, '"', raw_stdout);
fputs_unfiltered ("\"\n", raw_stdout);
fputs_unfiltered ("\"", raw_stdout);
switch (exception.error)
{
case UNDEFINED_COMMAND_ERROR:
fputs_unfiltered (",code=\"undefined-command\"", raw_stdout);
break;
}
fputs_unfiltered ("\n", raw_stdout);
}
void

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@ -285,7 +285,8 @@ mi_parse (const char *cmd, char **token)
/* Find the command in the MI table. */
parse->cmd = mi_lookup (parse->command);
if (parse->cmd == NULL)
error (_("Undefined MI command: %s"), parse->command);
throw_error (UNDEFINED_COMMAND_ERROR,
_("Undefined MI command: %s"), parse->command);
/* Skip white space following the command. */
chp = skip_spaces_const (chp);

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@ -1,3 +1,7 @@
2013-12-03 Joel Brobecker <brobecker@adacore.com>
* gdb.mi/mi-undefined-cmd.exp: New testcase.
2013-12-03 Joel Brobecker <brobecker@adacore.com>
* gdb.mi/mi-i-cmd.exp: New file.

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@ -0,0 +1,33 @@
# Copyright 2013 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/>.
load_lib mi-support.exp
set MIFLAGS "-i=mi"
gdb_exit
if [mi_gdb_start] {
continue
}
# First, verify that the debugger correctly advertises support
# for the "undefined-command" error code...
mi_gdb_test "-list-features" \
"\\^done,features=\\\[.*\"undefined-command-error-code\".*\\\]" \
"-list-features should include \"undefined-command-error-code\""
mi_gdb_test "-undefined-command" \
"\\^error,.*,code=\"undefined-command\"" \
"error code when executing undefined command"