[PATCH 3/3] Let Python breakpoints be created silently

[Tom Tromey <tromey@adacore.com>]

Currently, a breakpoint created from Python will always announce its
presence; and in some cases (for example a pending breakpoint), other
information will be printed as well.

When scripting gdb, it's useful to be able to control the output in
cases like this.  I debated whether to simply disable the output
entirely, but I thought perhaps some existing code acts as a simple
"break"-like command and wants the output.

This patch adds a new "announce" flag to gdb.Breakpoint.  Setting this
to False will cause gdb to be silent here.
---
 gdb/doc/python.texi                        | 10 ++++++--
 gdb/python/py-breakpoint.c                 | 30 +++++++++++++++++-----
 gdb/testsuite/gdb.python/py-breakpoint.exp |  3 ++-
 3 files changed, 34 insertions(+), 9 deletions(-)

diff --git a/gdb/doc/python.texi b/gdb/doc/python.texi
index 9cbb2f9f57d..bcbd3b271e8 100644
--- a/gdb/doc/python.texi
+++ b/gdb/doc/python.texi
@@ -5910,7 +5910,7 @@ create both breakpoints and watchpoints.  The second accepts separate Python
 arguments similar to @ref{Explicit Locations}, and can only be used to create
 breakpoints.
 
-@defun Breakpoint.__init__ (spec @r{[}, type @r{][}, wp_class @r{][}, internal @r{][}, temporary @r{][}, qualified @r{]})
+@defun Breakpoint.__init__ (spec @r{[}, type @r{][}, wp_class @r{][}, internal @r{][}, temporary @r{][}, qualified @r{][}, announce @r{]})
 Create a new breakpoint according to @var{spec}, which is a string naming the
 location of a breakpoint, or an expression that defines a watchpoint.  The
 string should describe a location in a format recognized by the @code{break}
@@ -5940,9 +5940,15 @@ the function passed in @code{spec} as a fully-qualified name.  It is equivalent
 to @code{break}'s @code{-qualified} flag (@pxref{Linespec Locations} and
 @ref{Explicit Locations}).
 
+The optional @var{announce} argument is a boolean that controls
+whether @var{GDBN} announces the existence of the breakpoint.  The
+default is to announce, meaning that a message is printed.  Setting
+this argument to false will suppress all output from breakpoint
+creation.
+
 @end defun
 
-@defun Breakpoint.__init__ (@r{[} source @r{][}, function @r{][}, label @r{][}, line @r{]}, @r{][} internal @r{][}, temporary @r{][}, qualified @r{]})
+@defun Breakpoint.__init__ (@r{[} source @r{][}, function @r{][}, label @r{][}, line @r{]}, @r{][} internal @r{][}, temporary @r{][}, qualified @r{][}, announce @r{]})
 This second form of creating a new breakpoint specifies the explicit
 location (@pxref{Explicit Locations}) using keywords.  The new breakpoint will
 be created in the specified source file @var{source}, at the specified
diff --git a/gdb/python/py-breakpoint.c b/gdb/python/py-breakpoint.c
index 39d9bd5dff6..f942a1c631e 100644
--- a/gdb/python/py-breakpoint.c
+++ b/gdb/python/py-breakpoint.c
@@ -903,7 +903,8 @@ bppy_init (PyObject *self, PyObject *args, PyObject *kwargs)
 {
   static const char *keywords[] = { "spec", "type", "wp_class", "internal",
 				    "temporary","source", "function",
-				    "label", "line", "qualified", NULL };
+				    "label", "line", "qualified",
+				    "announce", nullptr };
   const char *spec = NULL;
   enum bptype type = bp_breakpoint;
   int access_type = hw_write;
@@ -918,13 +919,15 @@ bppy_init (PyObject *self, PyObject *args, PyObject *kwargs)
   char *function = NULL;
   PyObject *qualified_obj = nullptr;
   int qualified = 0;
+  PyObject *announce_obj = nullptr;
+  int announce = 1;
 
-  if (!gdb_PyArg_ParseTupleAndKeywords (args, kwargs, "|siiOOsssOO", keywords,
+  if (!gdb_PyArg_ParseTupleAndKeywords (args, kwargs, "|siiOOsssOOO", keywords,
 					&spec, &type, &access_type,
 					&internal,
 					&temporary, &source,
 					&function, &label, &lineobj,
-					&qualified_obj))
+					&qualified_obj, &announce_obj))
     return -1;
 
 
@@ -963,6 +966,13 @@ bppy_init (PyObject *self, PyObject *args, PyObject *kwargs)
 	return -1;
     }
 
+  if (announce_obj != nullptr)
+    {
+      announce = PyObject_IsTrue (announce_obj);
+      if (announce == -1)
+	return -1;
+    }
+
   if (bppy_init_validate_args (spec, source, function, label, line.get (),
 			       type) == -1)
     return -1;
@@ -973,9 +983,17 @@ bppy_init (PyObject *self, PyObject *args, PyObject *kwargs)
 
   try
     {
-      bppy_create_breakpoint (type, access_type, temporary_bp, internal_bp,
-			      spec, qualified, source, function, label,
-			      line.get ());
+      if (announce)
+	bppy_create_breakpoint (type, access_type, temporary_bp, internal_bp,
+				spec, qualified, source, function,
+				label, line.get ());
+      else
+	execute_fn_to_ui_file (&null_stream, [&] ()
+	  {
+	    bppy_create_breakpoint (type, access_type, temporary_bp,
+				    internal_bp, spec, qualified,
+				    source, function, label, line.get ());
+	  });
     }
   catch (const gdb_exception &except)
     {
diff --git a/gdb/testsuite/gdb.python/py-breakpoint.exp b/gdb/testsuite/gdb.python/py-breakpoint.exp
index e36e87dc291..27f0619443e 100644
--- a/gdb/testsuite/gdb.python/py-breakpoint.exp
+++ b/gdb/testsuite/gdb.python/py-breakpoint.exp
@@ -544,7 +544,8 @@ proc_with_prefix test_bkpt_address {} {
 
 proc_with_prefix test_bkpt_pending {} {
     delete_breakpoints
-    gdb_breakpoint "nosuchfunction" allow-pending
+    gdb_test_no_output "python gdb.Breakpoint(\"nosuchfunction\", announce=False)" \
+	"create pending breakpoint"
     gdb_test "python print (gdb.breakpoints()\[0\].pending)" "True" \
 	"Check pending status of pending breakpoint"
 }
-- 
2.34.3