[geary/mjog/966-goa-retry-ensure-creds] GoaMediator: Re-try calling EnsureCredentials if auth error occurs

[Michael Gratton <mjog src gnome org>]

commit 17a7ad7eee510d5f9667c873d46e25f4ba587cd7
Author: Michael Gratton <mike vee net>
Date:   Wed Sep 2 11:23:22 2020 +1000

    GoaMediator: Re-try calling EnsureCredentials if auth error occurs
    
    Per GOA docs, if that calls fails with an auth error, we need to try
    it again.
    
    See #966

 src/client/application/goa-mediator.vala | 20 +++++++++++++++++---
 1 file changed, 17 insertions(+), 3 deletions(-)
---
diff --git a/src/client/application/goa-mediator.vala b/src/client/application/goa-mediator.vala
index baac0e6e6..bf92bb864 100644
--- a/src/client/application/goa-mediator.vala
+++ b/src/client/application/goa-mediator.vala
@@ -50,9 +50,23 @@ public class GoaMediator : Geary.CredentialsMediator, Object {
                                          Geary.ServiceInformation service,
                                          Cancellable? cancellable)
         throws GLib.Error {
-        yield this.handle.get_account().call_ensure_credentials(
-            cancellable, null
-        );
+        // Per GOA docs
+        // <https://developer.gnome.org/goa/stable/ch01s03.html>:
+        // "First the application should invoke the
+        // Account.EnsureCredentials() method […] if the service
+        // returns an authorization error (say, the access token
+        // expired), the application should call
+        // Account.EnsureCredentials() again to e.g. renew the
+        // credentials."
+        Goa.Account? goa_account = this.handle.get_account();
+        if (account != null) {
+            try {
+                yield goa_account.call_ensure_credentials(cancellable, null);
+            } catch (Goa.Error.NOT_AUTHORIZED err) {
+                debug("GOA updating auth failed, retrying: %s", err.message);
+                yield goa_account.call_ensure_credentials(cancellable, null);
+            }
+        }
 
         bool loaded = false;
         string? token = null;