[geary/mjog/composer-fixes: 1/2] Composer.Widget: Fix criticals when "mailto:" has empty body

[Michael Gratton <mjog src gnome org>]

commit bd85c4f1a82c14fad0f909e5b1058c73d5b56c92
Author: Michael Gratton <mike vee net>
Date:   Sun Sep 27 19:57:52 2020 +1000

    Composer.Widget: Fix criticals when "mailto:"; has empty body

 src/client/composer/composer-widget.vala       | 13 +++++++++----
 test/client/composer/composer-widget-test.vala | 10 ++++++++++
 2 files changed, 19 insertions(+), 4 deletions(-)
---
diff --git a/src/client/composer/composer-widget.vala b/src/client/composer/composer-widget.vala
index ecc3fbfdc..dab8cfd88 100644
--- a/src/client/composer/composer-widget.vala
+++ b/src/client/composer/composer-widget.vala
@@ -575,8 +575,11 @@ public class Composer.Widget : Gtk.EventBox, Geary.BaseInterface {
         Gee.HashMultiMap<string, string> headers = new Gee.HashMultiMap<string, string>();
         if (mailto.has_prefix(MAILTO_URI_PREFIX)) {
             // Parse the mailto link.
+            string? email = null;
             string[] parts = mailto.substring(MAILTO_URI_PREFIX.length).split("?", 2);
-            string email = Uri.unescape_string(parts[0]);
+            if (parts.length > 0) {
+                email = Uri.unescape_string(parts[0]);
+            }
             string[] params = parts.length == 2 ? parts[1].split("&") : new string[0];
             foreach (string param in params) {
                 string[] param_parts = param.split("=", 2);
@@ -587,14 +590,16 @@ public class Composer.Widget : Gtk.EventBox, Geary.BaseInterface {
             }
 
             // Assemble the headers.
-            if (email.length > 0 && headers.contains("to"))
+            if (!Geary.String.is_empty_or_whitespace(email) &&
+                headers.contains("to")) {
                 this.to = "%s,%s".printf(
                     email, Geary.Collection.first(headers.get("to"))
                 );
-            else if (email.length > 0)
+            } else if (!Geary.String.is_empty_or_whitespace(email)) {
                 this.to = email;
-            else if (headers.contains("to"))
+            } else if (headers.contains("to")) {
                 this.to = Geary.Collection.first(headers.get("to"));
+            }
 
             if (headers.contains("cc"))
                 this.cc = Geary.Collection.first(headers.get("cc"));
diff --git a/test/client/composer/composer-widget-test.vala b/test/client/composer/composer-widget-test.vala
index c35b52e44..6b31c9435 100644
--- a/test/client/composer/composer-widget-test.vala
+++ b/test/client/composer/composer-widget-test.vala
@@ -92,6 +92,7 @@ public class Composer.WidgetTest : TestCase {
         add_test("load_empty_body", load_empty_body);
         add_test("load_empty_body_to", load_empty_body_to);
         add_test("load_mailto", load_mailto);
+        add_test("load_mailto_empty", load_mailto_empty);
         add_test("load_context_edit", load_context_edit);
         add_test("load_context_reply_sender", load_context_reply_sender);
         add_test("load_context_reply_sender_with_reply_to", load_context_reply_sender_with_reply_to);
@@ -164,6 +165,15 @@ public class Composer.WidgetTest : TestCase {
         assert_equal(widget.to, "mailto example com");
     }
 
+    public void load_mailto_empty() throws GLib.Error {
+        var widget = new Widget(this.application, this.config, this.account);
+
+        widget.load_mailto.begin("mailto:";, this.async_completion);
+        widget.load_mailto.end(async_result());
+
+        assert_equal(widget.to, "");
+    }
+
     public void load_context_edit() throws GLib.Error {
         var widget = new Widget(this.application, this.config, this.account);
         var email = load_email(MESSAGE_WITH_REPLY_TO);