clang-plugin: Add a g_signal_connect() checker

This validates that:
 • The named signal exists on the given GObject subclass.
 • The type of the callback function matches that declared for the
   signal.

Unit tests are included.

4 files changed, 263 insertions, 0 deletions

diff --git a/tests/Makefile.am b/tests/Makefile.am
index 26d1c02..3fc9e91 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -8,6 +8,7 @@ C_LOG_COMPILER = $(top_srcdir)/tests/wrapper-compiler-errors
 c_tests = \
 	assertion-extraction.c \
 	assertion-extraction-return.c \
+	gsignal-connect.c \
 	gvariant-builder.c \
 	gvariant-get.c \
 	gvariant-get-child.c \
@@ -24,6 +25,8 @@ templates = \
 	assertion-return.tail.c \
 	generic.head.c \
 	generic.tail.c \
+	gsignal.head.c \
+	gsignal.tail.c \
 	gvariant.head.c \
 	gvariant.tail.c \
 	$(NULL)
diff --git a/tests/gsignal-connect.c b/tests/gsignal-connect.c
new file mode 100644
index 0000000..7f529bf
--- /dev/null
+++ b/tests/gsignal-connect.c
@@ -0,0 +1,174 @@
+/* Template: gsignal */
+
+/*
+ * No error
+ */
+{
+	GObject *some_object = g_malloc (5);  // only checking the type
+	g_signal_connect (some_object, "notify", (GCallback) object_notify_cb,
+	                  NULL);
+}
+
+/*
+ * No error
+ */
+{
+	GObject *some_object = g_malloc (5);  // only checking the type
+
+	// Detailed signal
+	// FIXME: Check the detail is a valid property name too?
+	g_signal_connect (some_object, "notify::something",
+	                  (GCallback) object_notify_cb, NULL);
+}
+
+/*
+ * No error
+ */
+{
+	GObject *some_object = g_malloc (5);  // only checking the type
+	g_signal_connect (some_object, "notify",
+	                  (GCallback) object_notify_proto_cb,
+	                  NULL);
+}
+
+/*
+ * Could not check type of handler for signal ‘GObject::notify’. Callback function declaration does not contain parameter types.
+ *                           (GCallback) object_notify_no_proto_cb,
+ *                                       ^
+ * note: expanded from macro 'g_signal_connect'
+ *     g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0)
+ *                                                            ^
+ */
+{
+	GObject *some_object = g_malloc (5);  // only checking the type
+	g_signal_connect (some_object, "notify",
+	                  (GCallback) object_notify_no_proto_cb,
+	                  NULL);
+}
+
+/*
+ * Incorrect return type from signal handler for signal ‘GObject::notify’. Expected ‘void’ but saw ‘gboolean’.
+ *                           (GCallback) object_notify_invalid_return_cb, NULL);
+ *                                       ^
+ * note: expanded from macro 'g_signal_connect'
+ *     g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0)
+ *                                                            ^
+ */
+{
+	GObject *some_object = g_malloc (5);  // only checking the type
+	g_signal_connect (some_object, "notify",
+	                  (GCallback) object_notify_invalid_return_cb, NULL);
+}
+
+/*
+ * Incorrect type for argument 1 in signal handler for signal ‘GObject::notify’. Expected ‘GObject *’ but saw ‘GIOStream *’.
+ *                           (GCallback) object_notify_invalid_parameter_subclass_cb,
+ *                                       ^
+ * note: expanded from macro 'g_signal_connect'
+ *     g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0)
+ *                                                            ^
+ */
+{
+	GObject *some_object = g_malloc (5);  // only checking the type
+	g_signal_connect (some_object, "notify",
+	                  (GCallback) object_notify_invalid_parameter_subclass_cb,
+	                  NULL);
+}
+
+/*
+ * Incorrect type for argument 1 in signal handler for signal ‘GObject::notify’. Expected ‘GObject *’ but saw ‘const GObject *’.
+ *                           (GCallback) object_notify_invalid_parameter_const_cb,
+ *                                       ^
+ * note: expanded from macro 'g_signal_connect'
+ *     g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0)
+ *                                                            ^
+ */
+{
+	GObject *some_object = g_malloc (5);  // only checking the type
+	g_signal_connect (some_object, "notify",
+	                  (GCallback) object_notify_invalid_parameter_const_cb,
+	                  NULL);
+}
+
+/*
+ * Incorrect type for argument 2 in signal handler for signal ‘GObject::notify’. Expected ‘GParamSpec *’ but saw ‘void *’.
+ *                           (GCallback) object_notify_invalid_parameter_middle_cb,
+ *                                       ^
+ * note: expanded from macro 'g_signal_connect'
+ *     g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0)
+ *                                                            ^
+ */
+{
+	GObject *some_object = g_malloc (5);  // only checking the type
+	g_signal_connect (some_object, "notify",
+	                  (GCallback) object_notify_invalid_parameter_middle_cb,
+	                  NULL);
+}
+
+/*
+ * Incorrect type for argument 3 in signal handler for signal ‘GObject::notify’. Expected ‘void *’ but saw ‘guint’.
+ *                           (GCallback) object_notify_invalid_parameter_user_data_cb,
+ *                                       ^
+ * note: expanded from macro 'g_signal_connect'
+ *     g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0)
+ *                                                            ^
+ */
+{
+	GObject *some_object = g_malloc (5);  // only checking the type
+	g_signal_connect (some_object, "notify",
+	                  (GCallback) object_notify_invalid_parameter_user_data_cb,
+	                  NULL);
+}
+
+/*
+ * No error
+ */
+{
+	// Non-void* pointer types for user_data are allowed.
+	GObject *some_object = g_malloc (5);  // only checking the type
+	g_signal_connect (some_object, "notify",
+	                  (GCallback) object_notify_invalid_parameter_user_data_ptr_cb,
+	                  NULL);
+}
+
+/*
+ * Incorrect number of arguments in signal handler for signal ‘GObject::notify’. Expected 3 but saw 2.
+ *                           (GCallback) object_notify_missing_parameter_cb, NULL);
+ *                                       ^
+ * note: expanded from macro 'g_signal_connect'
+ *     g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0)
+ *                                                            ^
+ */
+{
+	GObject *some_object = g_malloc (5);  // only checking the type
+	g_signal_connect (some_object, "notify",
+	                  (GCallback) object_notify_missing_parameter_cb, NULL);
+}
+
+/*
+ * Incorrect number of arguments in signal handler for signal ‘GObject::notify’. Expected 3 but saw 4.
+ *                           (GCallback) object_notify_extra_parameter_cb, NULL);
+ *                                       ^
+ * note: expanded from macro 'g_signal_connect'
+ *     g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0)
+ *                                                            ^
+ */
+{
+	GObject *some_object = g_malloc (5);  // only checking the type
+	g_signal_connect (some_object, "notify",
+	                  (GCallback) object_notify_extra_parameter_cb, NULL);
+}
+
+/*
+ * No signal named ‘invalid-signal’ in GObject class ‘Object’.
+ *         g_signal_connect (some_object, "invalid-signal",
+ *         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ * note: expanded from macro 'g_signal_connect'
+ *     g_signal_connect_data ((instance), (detailed_signal), (c_handler), (data), NULL, (GConnectFlags) 0)
+ *     ^                      ~~~~~~~~~~  ~~~~~~~~~~~~~~~~~
+ */
+{
+	GObject *some_object = g_malloc (5);  // only checking the type
+	g_signal_connect (some_object, "invalid-signal",
+	                  (GCallback) object_notify_cb, NULL);
+}
diff --git a/tests/gsignal.head.c b/tests/gsignal.head.c
new file mode 100644
index 0000000..8b6e1ac
--- /dev/null
+++ b/tests/gsignal.head.c
@@ -0,0 +1,82 @@
+#include <stdio.h>
+
+#include <glib.h>
+#include <glib-object.h>
+#include <gio/gio.h>
+
+static void
+object_notify_cb (GObject *gobject, GParamSpec *pspec, gpointer user_data)
+{
+	/* Something */
+}
+
+extern void
+object_notify_proto_cb (GObject *gobject, GParamSpec *pspec, gpointer user_data);
+
+extern void
+object_notify_no_proto_cb ();
+
+static gboolean
+object_notify_invalid_return_cb (GObject *gobject, GParamSpec *pspec,
+                                 gpointer user_data)
+{
+	/* Something */
+	return FALSE;
+}
+
+static void
+object_notify_invalid_parameter_subclass_cb (GIOStream *gobject,
+                                             GParamSpec *pspec,
+                                             gpointer user_data)
+{
+	/* Something */
+}
+
+static void
+object_notify_invalid_parameter_const_cb (const GObject *gobject,
+                                          GParamSpec *pspec,
+                                          gpointer user_data)
+{
+	/* Something */
+}
+
+static void
+object_notify_invalid_parameter_middle_cb (GObject *gobject,
+                                           void *pspec,
+                                           gpointer user_data)
+{
+	/* Something */
+}
+
+static void
+object_notify_invalid_parameter_user_data_cb (GObject *gobject,
+                                              GParamSpec *pspec,
+                                              guint user_data)
+{
+	/* Something */
+}
+
+static void
+object_notify_invalid_parameter_user_data_ptr_cb (GObject *gobject,
+                                                  GParamSpec *pspec,
+                                                  GObject *user_data)
+{
+	/* Something */
+}
+
+static void
+object_notify_missing_parameter_cb (GObject *gobject, GParamSpec *pspec)
+{
+	/* Something */
+}
+
+static void
+object_notify_extra_parameter_cb (GObject *gobject, GParamSpec *pspec,
+                                  gpointer user_data, gpointer user_data2)
+{
+	/* Something */
+}
+
+int
+main (void)
+{
diff --git a/tests/gsignal.tail.c b/tests/gsignal.tail.c
new file mode 100644
index 0000000..aa0c781
--- /dev/null
+++ b/tests/gsignal.tail.c
@@ -0,0 +1,4 @@
+	/* End of main(). */
+
+	return 0;
+}