[PATCH master + 11] gdb/mi: handle no condition argument case for -break-condition

[PATCH master + 11] gdb/mi: handle no condition argument case for -break-condition

[Tankut Baris Aktemur]

As reported in PR gdb/28076 [1], passing no condition argument to the
-break-condition command (e.g.: "-break-condition 2") should clear the
condition for breakpoint 2, just like CLI's "condition 2", but instead
an error message is returned:

  ^error,msg="-break-condition: Missing the <number> and/or <expr> argument"

The current implementation of the -break-condition command's argument
handling (79aabb7308c "gdb/mi: add a '--force' flag to the
'-break-condition' command") was done according to the documentation,
where the condition argument seemed mandatory.  However, the
-break-condition command originally (i.e. before the 79aabb7308c
patch) used the CLI's "cond" command, and back then not passing a
condition argument was clearing out the condition.  So, this is a
regression in terms of the behavior.

Fix the argument handling of the -break-condition command to allow not
having a condition argument, and also update the document to make the
behavior clear.  Also add test cases to test the scenarios which were
previously not covered.

[1] https://sourceware.org/bugzilla/show_bug.cgi?id=28076

gdb/ChangeLog:
2021-07-12  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	PR gdb/28076
	* mi/mi-cmd-break.c (mi_cmd_break_condition): Handle the case
	of having no condition argument.

gdb/doc/ChangeLog:
2021-07-12  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	PR gdb/28076
	* gdb.texinfo (GDB/MI Breakpoint Commands): Mention clearing
	the condition in the -break-condition command.

gdb/testsuite/ChangeLog:
2021-07-12  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>

	PR gdb/28076
	* gdb.mi/mi-break.exp: Add more tests to check clearing the
	breakpoint condition.
---
 gdb/doc/gdb.texinfo               |  5 +++--
 gdb/mi/mi-cmd-break.c             | 15 +++++++--------
 gdb/testsuite/gdb.mi/mi-break.exp | 22 ++++++++++++++++++++++
 3 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
index a16a3825ebb..a486bbe3607 100644
--- a/gdb/doc/gdb.texinfo
+++ b/gdb/doc/gdb.texinfo
@@ -30565,7 +30565,7 @@ times="0"@}
 @subsubheading Synopsis
 
 @smallexample
- -break-condition [ --force ] @var{number} @var{expr}
+ -break-condition [ --force ] @var{number} [ @var{expr} ]
 @end smallexample
 
 Breakpoint @var{number} will stop the program only if the condition in
@@ -30573,7 +30573,8 @@ Breakpoint @var{number} will stop the program only if the condition in
 @samp{-break-list} output (see the description of the @samp{-break-list}
 command below).  If the @samp{--force} flag is passed, the condition
 is forcibly defined even when it is invalid for all locations of
-breakpoint @var{number}.
+breakpoint @var{number}.  If the @var{expr} argument is omitted,
+breakpoint @var{number} becomes unconditional.
 
 @subsubheading @value{GDBN} Command
 
diff --git a/gdb/mi/mi-cmd-break.c b/gdb/mi/mi-cmd-break.c
index 5439937f66b..c2d642d75b4 100644
--- a/gdb/mi/mi-cmd-break.c
+++ b/gdb/mi/mi-cmd-break.c
@@ -423,20 +423,19 @@ mi_cmd_break_condition (const char *command, char **argv, int argc)
 	}
     }
 
-  /* There must be at least two more args: a bpnum and a condition
-     expression.  */
-  if (oind + 1 >= argc)
-    error (_("-break-condition: Missing the <number> and/or <expr> "
-	     "argument"));
+  /* There must be at least one more arg: a bpnum.  */
+  if (oind >= argc)
+    error (_("-break-condition: Missing the <number> argument"));
 
   int bpnum = atoi (argv[oind]);
 
   /* The rest form the condition expr.  */
-  std::string expr (argv[oind + 1]);
-  for (int i = oind + 2; i < argc; ++i)
+  std::string expr = "";
+  for (int i = oind + 1; i < argc; ++i)
     {
-      expr += " ";
       expr += argv[i];
+      if (i + 1 < argc)
+	expr += " ";
     }
 
   set_breakpoint_condition (bpnum, expr.c_str (), 0 /* from_tty */,
diff --git a/gdb/testsuite/gdb.mi/mi-break.exp b/gdb/testsuite/gdb.mi/mi-break.exp
index b6ef3483004..f8ff9beb7d2 100644
--- a/gdb/testsuite/gdb.mi/mi-break.exp
+++ b/gdb/testsuite/gdb.mi/mi-break.exp
@@ -435,6 +435,28 @@ proc_with_prefix test_forced_conditions {} {
     mi_gdb_test "-break-info 16" \
 	"\\^done,[mi_make_breakpoint_table [list $bp]]" \
         "invalid condition is defined"
+
+    # No cond argument should clear the condition.
+    mi_gdb_test "-break-condition 16" \
+        "~\"Breakpoint 16's condition is now valid at location 1, enabling.*\\^done" \
+        "clear the condition"
+    set bp [mi_make_breakpoint -number 16]
+    mi_gdb_test "-break-info 16" \
+	"\\^done,[mi_make_breakpoint_table [list $bp]]" \
+        "condition is cleared"
+
+    # Zero-argument is an error.
+    mi_gdb_test "-break-condition" \
+	"\\^error,msg=\"-break-condition: Missing the <number> argument\"" \
+        "no arguments to -break-condition"
+
+    # Passing --force with no condition should not crash or raise an error.
+    mi_gdb_test "-break-condition --force 16" \
+	"\\^done" \
+        "clear the condition with --force"
+    mi_gdb_test "-break-condition --force" \
+	"\\^error,msg=\"-break-condition: Missing the <number> argument\"" \
+        "no arguments with --force"
 }
 
 proc test_break {mi_mode} {
-- 
2.17.1

RE: [PATCH master + 11] gdb/mi: handle no condition argument case for -break-condition

[Aktemur, Tankut Baris]

On Monday, July 12, 2021 10:20 AM, Aktemur, Tankut Baris wrote:
> As reported in PR gdb/28076 [1], passing no condition argument to the
> -break-condition command (e.g.: "-break-condition 2") should clear the
> condition for breakpoint 2, just like CLI's "condition 2", but instead
> an error message is returned:
> 
>   ^error,msg="-break-condition: Missing the <number> and/or <expr> argument"
> 
> The current implementation of the -break-condition command's argument
> handling (79aabb7308c "gdb/mi: add a '--force' flag to the
> '-break-condition' command") was done according to the documentation,
> where the condition argument seemed mandatory.  However, the
> -break-condition command originally (i.e. before the 79aabb7308c
> patch) used the CLI's "cond" command, and back then not passing a
> condition argument was clearing out the condition.  So, this is a
> regression in terms of the behavior.
> 
> Fix the argument handling of the -break-condition command to allow not
> having a condition argument, and also update the document to make the
> behavior clear.  Also add test cases to test the scenarios which were
> previously not covered.
> 
> [1] https://sourceware.org/bugzilla/show_bug.cgi?id=28076
> 
> gdb/ChangeLog:
> 2021-07-12  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>
> 
> 	PR gdb/28076
> 	* mi/mi-cmd-break.c (mi_cmd_break_condition): Handle the case
> 	of having no condition argument.
> 
> gdb/doc/ChangeLog:
> 2021-07-12  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>
> 
> 	PR gdb/28076
> 	* gdb.texinfo (GDB/MI Breakpoint Commands): Mention clearing
> 	the condition in the -break-condition command.
> 
> gdb/testsuite/ChangeLog:
> 2021-07-12  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>
> 
> 	PR gdb/28076
> 	* gdb.mi/mi-break.exp: Add more tests to check clearing the
> 	breakpoint condition.
> ---
>  gdb/doc/gdb.texinfo               |  5 +++--
>  gdb/mi/mi-cmd-break.c             | 15 +++++++--------
>  gdb/testsuite/gdb.mi/mi-break.exp | 22 ++++++++++++++++++++++
>  3 files changed, 32 insertions(+), 10 deletions(-)
> 
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index a16a3825ebb..a486bbe3607 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -30565,7 +30565,7 @@ times="0"@}
>  @subsubheading Synopsis
> 
>  @smallexample
> - -break-condition [ --force ] @var{number} @var{expr}
> + -break-condition [ --force ] @var{number} [ @var{expr} ]
>  @end smallexample
> 
>  Breakpoint @var{number} will stop the program only if the condition in
> @@ -30573,7 +30573,8 @@ Breakpoint @var{number} will stop the program only if the condition
> in
>  @samp{-break-list} output (see the description of the @samp{-break-list}
>  command below).  If the @samp{--force} flag is passed, the condition
>  is forcibly defined even when it is invalid for all locations of
> -breakpoint @var{number}.
> +breakpoint @var{number}.  If the @var{expr} argument is omitted,
> +breakpoint @var{number} becomes unconditional.
> 
>  @subsubheading @value{GDBN} Command
> 
> diff --git a/gdb/mi/mi-cmd-break.c b/gdb/mi/mi-cmd-break.c
> index 5439937f66b..c2d642d75b4 100644
> --- a/gdb/mi/mi-cmd-break.c
> +++ b/gdb/mi/mi-cmd-break.c
> @@ -423,20 +423,19 @@ mi_cmd_break_condition (const char *command, char **argv, int argc)
>  	}
>      }
> 
> -  /* There must be at least two more args: a bpnum and a condition
> -     expression.  */
> -  if (oind + 1 >= argc)
> -    error (_("-break-condition: Missing the <number> and/or <expr> "
> -	     "argument"));
> +  /* There must be at least one more arg: a bpnum.  */
> +  if (oind >= argc)
> +    error (_("-break-condition: Missing the <number> argument"));
> 
>    int bpnum = atoi (argv[oind]);
> 
>    /* The rest form the condition expr.  */
> -  std::string expr (argv[oind + 1]);
> -  for (int i = oind + 2; i < argc; ++i)
> +  std::string expr = "";
> +  for (int i = oind + 1; i < argc; ++i)
>      {
> -      expr += " ";
>        expr += argv[i];
> +      if (i + 1 < argc)
> +	expr += " ";
>      }
> 
>    set_breakpoint_condition (bpnum, expr.c_str (), 0 /* from_tty */,
> diff --git a/gdb/testsuite/gdb.mi/mi-break.exp b/gdb/testsuite/gdb.mi/mi-break.exp
> index b6ef3483004..f8ff9beb7d2 100644
> --- a/gdb/testsuite/gdb.mi/mi-break.exp
> +++ b/gdb/testsuite/gdb.mi/mi-break.exp
> @@ -435,6 +435,28 @@ proc_with_prefix test_forced_conditions {} {
>      mi_gdb_test "-break-info 16" \
>  	"\\^done,[mi_make_breakpoint_table [list $bp]]" \
>          "invalid condition is defined"
> +
> +    # No cond argument should clear the condition.
> +    mi_gdb_test "-break-condition 16" \
> +        "~\"Breakpoint 16's condition is now valid at location 1, enabling.*\\^done" \
> +        "clear the condition"
> +    set bp [mi_make_breakpoint -number 16]
> +    mi_gdb_test "-break-info 16" \
> +	"\\^done,[mi_make_breakpoint_table [list $bp]]" \
> +        "condition is cleared"
> +
> +    # Zero-argument is an error.
> +    mi_gdb_test "-break-condition" \
> +	"\\^error,msg=\"-break-condition: Missing the <number> argument\"" \
> +        "no arguments to -break-condition"
> +
> +    # Passing --force with no condition should not crash or raise an error.
> +    mi_gdb_test "-break-condition --force 16" \
> +	"\\^done" \
> +        "clear the condition with --force"
> +    mi_gdb_test "-break-condition --force" \
> +	"\\^error,msg=\"-break-condition: Missing the <number> argument\"" \
> +        "no arguments with --force"

There are space vs. tab problems above.  I've fixed them on my local branch.

-Baris


Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

Re: [PATCH master + 11] gdb/mi: handle no condition argument case for -break-condition

[Jonah Graham]

On Mon, 12 Jul 2021 at 04:20, Tankut Baris Aktemur <
tankut.baris.aktemur@intel.com> wrote:

> As reported in PR gdb/28076 [1], passing no condition argument to the
>

Thanks Baris. I have applied the patch and it works well. Thanks for fixing
the docs too!


> +    error (_("-break-condition: Missing the <number> argument"));
>

The error message has changed compared to previous GDB releases, not sure
if that was intentional or if it matters, the old versions said:

^error,msg="Argument required (breakpoint number)."

the new message renders as:

^error,msg="-break-condition: Missing the <number> argument"

Eclipse CDT does not use the contents of error message (because we never
send a command with such an error :-) so from my perspective it is fine to
change the error message.

Jonah




>
>

RE: [PATCH master + 11] gdb/mi: handle no condition argument case for -break-condition

[Aktemur, Tankut Baris]

From: Jonah Graham <jonah@kichwacoders.com>
Sent: Monday, July 12, 2021 3:37 PM
To: Aktemur, Tankut Baris <tankut.baris.aktemur@intel.com>
Cc: gdb-patches@sourceware.org; Simon Marchi <simon.marchi@polymtl.ca>
Subject: Re: [PATCH master + 11] gdb/mi: handle no condition argument case for -break-condition

The error message has changed compared to previous GDB releases, not sure if that was intentional or if it matters, the old versions said:

^error,msg="Argument required (breakpoint number)."

the new message renders as:

^error,msg="-break-condition: Missing the <number> argument"

Eclipse CDT does not use the contents of error message (because we never send a command with such an error :-) so from my perspective it is fine to change the error message.

Jonah

The former error message was coming from the CLI’s “cond” command:

  (gdb) cond
  Argument required (breakpoint number).

In my opinion this message is equivalent to the new message in terms of descriptiveness,
except for the “-break-condition” prefix.  Let’s see what Simon or another maintainer
thinks about preserving the exact same error message.

Thanks
-Baris


Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

Re: [PATCH master + 11] gdb/mi: handle no condition argument case for -break-condition

[Simon Marchi]

> The error message has changed compared to previous GDB releases, not sure if that was intentional or if it matters, the old versions said:
> 
>  
> 
> ^error,msg="Argument required (breakpoint number)."
> 
>  
> 
> the new message renders as:
> 
>  
> 
> ^error,msg="-break-condition: Missing the <number> argument"
> 
>  
> 
> Eclipse CDT does not use the contents of error message (because we never send a command with such an error :-) so from my perspective it is fine to change the error message.
> 
>  
> 
> Jonah
> 
>      
> 
> The former error message was coming from the CLI’s “cond” command:
> 
>  
> 
>   (gdb) cond
> 
>   Argument required (breakpoint number).
> 
>  
> 
> In my opinion this message is equivalent to the new message in terms of descriptiveness,
> 
> except for the “-break-condition” prefix.  Let’s see what Simon or another maintainer
> 
> thinks about preserving the exact same error message.

I really don't mind.  The code part of the patch LGTM.  Eli, any
comments on the doc?

Simon

Re: [PATCH master + 11] gdb/mi: handle no condition argument case for -break-condition

[Joel Brobecker]

Hi Eli,

The code change for this patch has been approved by Simon.
I was hoping you could take a look at the documentation changes
for Tankut?

thank you!

On Mon, Jul 12, 2021 at 10:20:01AM +0200, Tankut Baris Aktemur via Gdb-patches wrote:
> As reported in PR gdb/28076 [1], passing no condition argument to the
> -break-condition command (e.g.: "-break-condition 2") should clear the
> condition for breakpoint 2, just like CLI's "condition 2", but instead
> an error message is returned:
> 
>   ^error,msg="-break-condition: Missing the <number> and/or <expr> argument"
> 
> The current implementation of the -break-condition command's argument
> handling (79aabb7308c "gdb/mi: add a '--force' flag to the
> '-break-condition' command") was done according to the documentation,
> where the condition argument seemed mandatory.  However, the
> -break-condition command originally (i.e. before the 79aabb7308c
> patch) used the CLI's "cond" command, and back then not passing a
> condition argument was clearing out the condition.  So, this is a
> regression in terms of the behavior.
> 
> Fix the argument handling of the -break-condition command to allow not
> having a condition argument, and also update the document to make the
> behavior clear.  Also add test cases to test the scenarios which were
> previously not covered.
> 
> [1] https://sourceware.org/bugzilla/show_bug.cgi?id=28076
> 
> gdb/ChangeLog:
> 2021-07-12  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>
> 
> 	PR gdb/28076
> 	* mi/mi-cmd-break.c (mi_cmd_break_condition): Handle the case
> 	of having no condition argument.
> 
> gdb/doc/ChangeLog:
> 2021-07-12  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>
> 
> 	PR gdb/28076
> 	* gdb.texinfo (GDB/MI Breakpoint Commands): Mention clearing
> 	the condition in the -break-condition command.
> 
> gdb/testsuite/ChangeLog:
> 2021-07-12  Tankut Baris Aktemur  <tankut.baris.aktemur@intel.com>
> 
> 	PR gdb/28076
> 	* gdb.mi/mi-break.exp: Add more tests to check clearing the
> 	breakpoint condition.
> ---
>  gdb/doc/gdb.texinfo               |  5 +++--
>  gdb/mi/mi-cmd-break.c             | 15 +++++++--------
>  gdb/testsuite/gdb.mi/mi-break.exp | 22 ++++++++++++++++++++++
>  3 files changed, 32 insertions(+), 10 deletions(-)
> 
> diff --git a/gdb/doc/gdb.texinfo b/gdb/doc/gdb.texinfo
> index a16a3825ebb..a486bbe3607 100644
> --- a/gdb/doc/gdb.texinfo
> +++ b/gdb/doc/gdb.texinfo
> @@ -30565,7 +30565,7 @@ times="0"@}
>  @subsubheading Synopsis
>  
>  @smallexample
> - -break-condition [ --force ] @var{number} @var{expr}
> + -break-condition [ --force ] @var{number} [ @var{expr} ]
>  @end smallexample
>  
>  Breakpoint @var{number} will stop the program only if the condition in
> @@ -30573,7 +30573,8 @@ Breakpoint @var{number} will stop the program only if the condition in
>  @samp{-break-list} output (see the description of the @samp{-break-list}
>  command below).  If the @samp{--force} flag is passed, the condition
>  is forcibly defined even when it is invalid for all locations of
> -breakpoint @var{number}.
> +breakpoint @var{number}.  If the @var{expr} argument is omitted,
> +breakpoint @var{number} becomes unconditional.
>  
>  @subsubheading @value{GDBN} Command
>  
> diff --git a/gdb/mi/mi-cmd-break.c b/gdb/mi/mi-cmd-break.c
> index 5439937f66b..c2d642d75b4 100644
> --- a/gdb/mi/mi-cmd-break.c
> +++ b/gdb/mi/mi-cmd-break.c
> @@ -423,20 +423,19 @@ mi_cmd_break_condition (const char *command, char **argv, int argc)
>  	}
>      }
>  
> -  /* There must be at least two more args: a bpnum and a condition
> -     expression.  */
> -  if (oind + 1 >= argc)
> -    error (_("-break-condition: Missing the <number> and/or <expr> "
> -	     "argument"));
> +  /* There must be at least one more arg: a bpnum.  */
> +  if (oind >= argc)
> +    error (_("-break-condition: Missing the <number> argument"));
>  
>    int bpnum = atoi (argv[oind]);
>  
>    /* The rest form the condition expr.  */
> -  std::string expr (argv[oind + 1]);
> -  for (int i = oind + 2; i < argc; ++i)
> +  std::string expr = "";
> +  for (int i = oind + 1; i < argc; ++i)
>      {
> -      expr += " ";
>        expr += argv[i];
> +      if (i + 1 < argc)
> +	expr += " ";
>      }
>  
>    set_breakpoint_condition (bpnum, expr.c_str (), 0 /* from_tty */,
> diff --git a/gdb/testsuite/gdb.mi/mi-break.exp b/gdb/testsuite/gdb.mi/mi-break.exp
> index b6ef3483004..f8ff9beb7d2 100644
> --- a/gdb/testsuite/gdb.mi/mi-break.exp
> +++ b/gdb/testsuite/gdb.mi/mi-break.exp
> @@ -435,6 +435,28 @@ proc_with_prefix test_forced_conditions {} {
>      mi_gdb_test "-break-info 16" \
>  	"\\^done,[mi_make_breakpoint_table [list $bp]]" \
>          "invalid condition is defined"
> +
> +    # No cond argument should clear the condition.
> +    mi_gdb_test "-break-condition 16" \
> +        "~\"Breakpoint 16's condition is now valid at location 1, enabling.*\\^done" \
> +        "clear the condition"
> +    set bp [mi_make_breakpoint -number 16]
> +    mi_gdb_test "-break-info 16" \
> +	"\\^done,[mi_make_breakpoint_table [list $bp]]" \
> +        "condition is cleared"
> +
> +    # Zero-argument is an error.
> +    mi_gdb_test "-break-condition" \
> +	"\\^error,msg=\"-break-condition: Missing the <number> argument\"" \
> +        "no arguments to -break-condition"
> +
> +    # Passing --force with no condition should not crash or raise an error.
> +    mi_gdb_test "-break-condition --force 16" \
> +	"\\^done" \
> +        "clear the condition with --force"
> +    mi_gdb_test "-break-condition --force" \
> +	"\\^error,msg=\"-break-condition: Missing the <number> argument\"" \
> +        "no arguments with --force"
>  }
>  
>  proc test_break {mi_mode} {
> -- 
> 2.17.1
> 

-- 
Joel

Re: [PATCH master + 11] gdb/mi: handle no condition argument case for -break-condition

[Eli Zaretskii]

> Date: Sat, 24 Jul 2021 14:15:24 -0700
> From: Joel Brobecker <brobecker@adacore.com>
> Cc: Joel Brobecker <brobecker@adacore.com>
> 
> Hi Eli,
> 
> The code change for this patch has been approved by Simon.
> I was hoping you could take a look at the documentation changes
> for Tankut?

Oops, sorry for missing it.  Yes, the documentation parts are okay.