[vala/staging] vala: DBus methods are recommended to throw at least DBusError or IOError

[Rico Tzschichholz <ricotz src gnome org>]

commit 13c5eb638ecd69bedb7c0d676defc8d141aff0d0
Author: Dr. Michael Lauer <mickey vanille-media de>
Date:   Sun Feb 11 17:18:35 2018 +0100

    vala: DBus methods are recommended to throw at least DBusError or IOError
    
    This issues a warning now and will be turned into an error at some point.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=792277

 tests/Makefile.am         |    1 +
 tests/dbus/bug792277.vala |   26 ++++++++++++++++++++++++++
 vala/valamethod.vala      |   22 ++++++++++++++++++++++
 3 files changed, 49 insertions(+), 0 deletions(-)
---
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 7b9d57c..decdb14 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -363,6 +363,7 @@ TESTS = \
        dbus/bug596862.vala \
        dbus/bug602003.test \
        dbus/bug782719.test \
+       dbus/bug792277.vala \
        dbus/rawvariants.test \
        gir/bug651773.test \
        gir/bug667751.test \
diff --git a/tests/dbus/bug792277.vala b/tests/dbus/bug792277.vala
new file mode 100644
index 0000000..5644019
--- /dev/null
+++ b/tests/dbus/bug792277.vala
@@ -0,0 +1,26 @@
+[DBus (name = "org.example.IFoo")]
+public interface IFoo : Object {
+       public abstract void method0 () throws IOError;
+       public abstract void method1 () throws DBusError;
+       [DBus (visible = false)]
+       public abstract void method2 () throws Error;
+       [DBus (visible = false)]
+       public abstract void method3 ();
+}
+
+[DBus (name = "org.example.Foo")]
+public class Foo : Object {
+       public void method0 () throws IOError {
+       }
+       public void method1 () throws DBusError {
+       }
+       [DBus (visible = false)]
+       public void method2 () throws Error {
+       }
+       [DBus (visible = false)]
+       public void method3 () {
+       }
+}
+
+void main () {
+}
diff --git a/vala/valamethod.vala b/vala/valamethod.vala
index 8af2f66..341e86b 100644
--- a/vala/valamethod.vala
+++ b/vala/valamethod.vala
@@ -856,6 +856,28 @@ public class Vala.Method : Subroutine, Callable {
                        }
                }
 
+               // check that DBus methods at least throw GLib.DBusError or GLib.IOError
+               if (parent_symbol is ObjectTypeSymbol && parent_symbol.get_attribute ("DBus") != null) {
+                       Attribute? dbus_attr = get_attribute ("DBus");
+                       if (dbus_attr == null || dbus_attr.get_bool ("visible", true)) {
+                               bool throws_required_error = false;
+                               foreach (DataType error_type in get_error_types ()) {
+                                       if (!(error_type is ErrorType)) {
+                                               continue;
+                                       }
+                                       unowned ErrorDomain? error_domain = ((ErrorType) 
error_type).error_domain;
+                                       string? full_error_domain = (error_domain == null ? null : 
error_domain.get_full_name ());
+                                       if (full_error_domain == "GLib.DBusError" || full_error_domain == 
"GLib.IOError") {
+                                               throws_required_error = true;
+                                               break;
+                                       }
+                               }
+                               if (!throws_required_error) {
+                                       Report.warning (source_reference, "DBus methods are recommended to 
throw at least `GLib.DBusError' or `GLib.IOError'");
+                               }
+                       }
+               }
+
                if (is_possible_entry_point (context)) {
                        if (context.entry_point != null) {
                                error = true;