Add Check for Using Directive

README.md

@@ -85,6 +85,7 @@ use-of-tabs=error
 trailing-newlines=error
 trailing-whitespace=error
 unnecessary-string-template=error
+using-directive=error
 
 [Disabler]
 disable-by-inline-comments=true

lib/Checks/UsingDirectiveCheck.vala

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2019 elementary LLC. (https://github.com/elementary/vala-lint)
+ *
+ * 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 2 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, write to the
+ * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301 USA.
+ */
+
+public class ValaLint.Checks.UsingDirectiveCheck : Check {
+    const string MESSAGE = _("Use explicit namespace instead");
+
+    public UsingDirectiveCheck () {
+        Object (
+            title: "using-directive",
+            description: _("Checks for undesirable using directives")
+        );
+
+        state = Config.get_state (title);
+    }
+
+    public override void check (Vala.ArrayList<ParseResult?> parse_result,
+                                ref Vala.ArrayList<FormatMistake?> mistake_list) {
+
+    }
+
+    public void check_using_directive (Vala.UsingDirective ns, ref Vala.ArrayList<FormatMistake?> mistake_list) {
+        if (state == Config.State.OFF) {
+            return;
+        }
+
+        var pos = ns.source_reference;
+        add_mistake ({ this, pos.begin, pos.end, MESSAGE }, ref mistake_list);
+    }
+}

lib/Config.vala

@@ -57,6 +57,7 @@ public class ValaLint.Config {
         default_config.set_string ("Checks", "trailing-newlines", State.ERROR.to_string ());
         default_config.set_string ("Checks", "trailing-whitespace", State.ERROR.to_string ());
         default_config.set_string ("Checks", "unnecessary-string-template", State.ERROR.to_string ());
+        default_config.set_string ("Checks", "using-directive", State.ERROR.to_string ());
 
         default_config.set_boolean ("Disabler", "disable-by-inline-comments", true);
 

lib/Linter.vala

@@ -51,6 +51,7 @@ public class ValaLint.Linter : Object {
         visitor.naming_convention_check = new Checks.NamingConventionCheck ();
         visitor.no_space_check = new Checks.NoSpaceCheck ();
         visitor.unnecessary_string_template_check = new Checks.UnnecessaryStringTemplateCheck ();
+        visitor.using_directive_check = new Checks.UsingDirectiveCheck ();
     }
 
     public Vala.ArrayList<FormatMistake?> run_checks_for_file (File file) throws Error, IOError {

lib/ValaVisitor.vala

@@ -25,13 +25,21 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     public Checks.NamingConventionCheck naming_convention_check;
     public Checks.UnnecessaryStringTemplateCheck unnecessary_string_template_check;
     public Checks.NoSpaceCheck no_space_check;
+    public Checks.UsingDirectiveCheck using_directive_check;
 
     public void set_mistake_list (Vala.ArrayList<FormatMistake?> mistake_list) {
         this.mistake_list = mistake_list;
     }
 
     public override void visit_source_file (Vala.SourceFile sf) {
         sf.accept_children (this);
+
+        /* using directives are not accepted by default */
+        foreach (var using_directives in sf.current_using_directives) {
+            if (using_directives.source_reference != null) {
+                using_directives.accept (this);
+            }
+        }
     }
 
     public override void visit_namespace (Vala.Namespace ns) {
@@ -139,6 +147,8 @@ class ValaLint.Visitor : Vala.CodeVisitor {
     }
 
     public override void visit_using_directive (Vala.UsingDirective ns) {
+        using_directive_check.check_using_directive (ns, ref mistake_list);
+
         ns.accept_children (this);
     }
 

lib/meson.build

@@ -22,6 +22,7 @@ vala_linter_files = files(
     'Checks/TrailingNewlinesCheck.vala',
     'Checks/TrailingWhitespaceCheck.vala',
     'Checks/UnnecessaryStringTemplateCheck.vala',
+    'Checks/UsingDirectiveCheck.vala',
 )
 
 vala_linter_deps = [

test/FileTest.vala

@@ -55,7 +55,8 @@ class FileTest : GLib.Object {
 
         int line = 0; // So that new tests can be added without changing every number...
         var m_warnings = new Vala.ArrayList<FileTestMistake?> ();
-        m_warnings.add ({ "naming-convention", line += 4 });
+        m_warnings.add ({ "using-directive", line += 3 });
+        m_warnings.add ({ "naming-convention", line += 3 });
         m_warnings.add ({ "space-before-paren", line += 2 });
         m_warnings.add ({ "note", line += 1, "TODO" });
         m_warnings.add ({ "note", line += 1, "TODO: Lorem ipsum" });

test/files/warnings.vala

@@ -1,6 +1,8 @@
 // vala-lint=skip-file
 
-class FileTest : GLib.Object {
+using GLib;
+
+class FileTest : Object {
     const int underscore_constant = 3;
 
     public static int main(string[] args) {

vala-lint.conf

@@ -12,6 +12,7 @@ use-of-tabs=error
 trailing-newlines=error
 trailing-whitespace=error
 unnecessary-string-template=error
+using-directive=error
 
 [Disabler]
 disable-by-inline-comments=true