[geary/wip/181-special-folder-dupes: 4/7] Ensure MinimalFolder remote open forces closed on hard errors

[Michael Gratton <mjog src gnome org>]

commit 46bb4d1b6cf90f120cd77ff1fcdae3596b4659fc
Author: Michael Gratton <mike vee net>
Date:   Mon Jan 14 11:29:27 2019 +1100

    Ensure MinimalFolder remote open forces closed on hard errors
    
    Minimal folder should force a folder closed when an error occurrs that
    it isn't going to be able to recover from.

 .../imap-engine/imap-engine-minimal-folder.vala    | 18 +++--
 .../imap-engine/imap-engine-replay-queue.vala      |  8 +--
 src/engine/imap-engine/imap-engine.vala            | 79 ++++++++++++----------
 3 files changed, 61 insertions(+), 44 deletions(-)
---
diff --git a/src/engine/imap-engine/imap-engine-minimal-folder.vala 
b/src/engine/imap-engine/imap-engine-minimal-folder.vala
index ed3d9f09..e9204bba 100644
--- a/src/engine/imap-engine/imap-engine-minimal-folder.vala
+++ b/src/engine/imap-engine/imap-engine-minimal-folder.vala
@@ -960,12 +960,18 @@ private class Geary.ImapEngine.MinimalFolder : Geary.Folder, Geary.FolderSupport
             );
             return;
         } catch (Error err) {
-            debug("Other error: %s", err.message);
-            // Notify that there was a connection error, but don't
-            // force the folder closed, since it might come good again
-            // if the user fixes an auth problem or the network comes
-            // back or whatever.
-            notify_open_failed(Folder.OpenFailed.REMOTE_ERROR, err);
+            ErrorContext context = new ErrorContext(err);
+            if (is_unrecoverable_failure(err)) {
+                debug("Unrecoverable failure opening remote, forcing closed: %s",
+                      context.format_full_error());
+                yield force_close(
+                    CloseReason.LOCAL_CLOSE, CloseReason.REMOTE_ERROR
+                );
+            } else {
+                debug("Recoverable error opening remote: %s",
+                      context.format_full_error());
+                notify_open_failed(Folder.OpenFailed.REMOTE_ERROR, err);
+            }
             return;
         }
 
diff --git a/src/engine/imap-engine/imap-engine-replay-queue.vala 
b/src/engine/imap-engine/imap-engine-replay-queue.vala
index 7238ffa0..8d5e2e61 100644
--- a/src/engine/imap-engine/imap-engine-replay-queue.vala
+++ b/src/engine/imap-engine/imap-engine-replay-queue.vala
@@ -519,11 +519,11 @@ private class Geary.ImapEngine.ReplayQueue : Geary.BaseObject {
                 } catch (Error replay_err) {
                     debug("Replay remote error for %s on %s: %s (%s)", op.to_string(), to_string(),
                         replay_err.message, op.on_remote_error.to_string());
-                    
-                    // If a hard failure and operation allows remote replay and not closing,
-                    // re-schedule now
+
+                    // If a recoverable failure and operation allows
+                    // remote replay and not closing, re-schedule now
                     if ((op.on_remote_error == ReplayOperation.OnError.RETRY)
-                        && is_hard_failure(replay_err)
+                        && !is_unrecoverable_failure(replay_err)
                         && state == State.OPEN) {
                         debug("Schedule op retry %s on %s", op.to_string(), to_string());
                         
diff --git a/src/engine/imap-engine/imap-engine.vala b/src/engine/imap-engine/imap-engine.vala
index 5bad3088..998bb1b8 100644
--- a/src/engine/imap-engine/imap-engine.vala
+++ b/src/engine/imap-engine/imap-engine.vala
@@ -6,40 +6,51 @@
 
 namespace Geary.ImapEngine {
 
-/**
- * A hard failure is defined as one due to hardware or connectivity issues, where a soft failure
- * is due to software reasons, like credential failure or protocol violation.
- */
-private static bool is_hard_failure(Error err) {
-    // CANCELLED is not a hard error
-    if (err is IOError.CANCELLED)
-        return false;
-
-    // Treat other errors -- most likely IOErrors -- as hard failures
-    if (!(err is ImapError) && !(err is EngineError))
-        return true;
-
-    return err is ImapError.NOT_CONNECTED
-        || err is ImapError.TIMED_OUT
-        || err is ImapError.SERVER_ERROR
-        || err is EngineError.SERVER_UNAVAILABLE;
-}
+    /**
+     * Determines if retrying an operation might succeed or not.
+     *
+     * A recoverable failure is defined as one that may not occur
+     * again if the operation that caused it is retried, without
+     * needing to make some change in the mean time. For example,
+     * recoverable failures may occur due to transient network
+     * connectivity issues or server rate limiting. On the other hand,
+     * an unrecoverable failure is due to some problem that will not
+     * succeed if tried again unless some action is taken, such as
+     * authentication failures, protocol parsing errors, and so on.
+     */
+    private static bool is_unrecoverable_failure(GLib.Error err) {
+        return !(
+            err is EngineError.SERVER_UNAVAILABLE ||
+            err is IOError.BROKEN_PIPE ||
+            err is IOError.BUSY ||
+            err is IOError.CONNECTION_CLOSED ||
+            err is IOError.NOT_CONNECTED ||
+            err is IOError.TIMED_OUT ||
+            err is ImapError.NOT_CONNECTED ||
+            err is ImapError.TIMED_OUT ||
+            err is ImapError.UNAVAILABLE
+        );
+    }
 
-/**
- * Determines if this IOError related to a remote host or not.
- */
-private static bool is_remote_error(GLib.Error err) {
-    return err is ImapError
-        || err is IOError.CONNECTION_CLOSED
-        || err is IOError.CONNECTION_REFUSED
-        || err is IOError.HOST_UNREACHABLE
-        || err is IOError.MESSAGE_TOO_LARGE
-        || err is IOError.NETWORK_UNREACHABLE
-        || err is IOError.NOT_CONNECTED
-        || err is IOError.PROXY_AUTH_FAILED
-        || err is IOError.PROXY_FAILED
-        || err is IOError.PROXY_NEED_AUTH
-        || err is IOError.PROXY_NOT_ALLOWED;
-}
+    /**
+     * Determines if an error was caused by the remote host or not.
+     */
+    private static bool is_remote_error(GLib.Error err) {
+        return (
+            err is EngineError.NOT_FOUND ||
+            err is EngineError.SERVER_UNAVAILABLE ||
+            err is IOError.CONNECTION_CLOSED ||
+            err is IOError.CONNECTION_REFUSED ||
+            err is IOError.HOST_UNREACHABLE ||
+            err is IOError.MESSAGE_TOO_LARGE ||
+            err is IOError.NETWORK_UNREACHABLE ||
+            err is IOError.NOT_CONNECTED ||
+            err is IOError.PROXY_AUTH_FAILED ||
+            err is IOError.PROXY_FAILED ||
+            err is IOError.PROXY_NEED_AUTH ||
+            err is IOError.PROXY_NOT_ALLOWED ||
+            err is ImapError
+        );
+    }
 
 }