[geary/mjog/fix-null-message-ids: 4/4] Make serialisation of Geary.Email.Field more usable

[Michael Gratton <mjog src gnome org>]

commit 47927aaff4402263ed9908aa4b5bb597f14e886e
Author: Michael Gratton <mike vee net>
Date:   Fri Nov 1 15:48:19 2019 +1100

    Make serialisation of Geary.Email.Field more usable

 src/engine/api/geary-email.vala              | 27 +++++++++++++++++----------
 src/engine/imap-db/imap-db-folder.vala       | 16 ++++++++++------
 src/engine/imap/api/imap-folder-session.vala | 17 ++++++++++++-----
 3 files changed, 39 insertions(+), 21 deletions(-)
---
diff --git a/src/engine/api/geary-email.vala b/src/engine/api/geary-email.vala
index 2b4d7ec4..04a2cdb4 100644
--- a/src/engine/api/geary-email.vala
+++ b/src/engine/api/geary-email.vala
@@ -157,18 +157,25 @@ public class Geary.Email : BaseObject, EmailHeaderSet {
             return is_any_set(required_fields);
         }
 
-        public string to_list_string() {
-            StringBuilder builder = new StringBuilder();
-            foreach (Field f in all()) {
-                if (is_all_set(f)) {
-                    if (!String.is_empty(builder.str))
-                        builder.append(", ");
-
-                    builder.append(f.to_string());
+        public string to_string() {
+            string value = "NONE";
+            if (this == ALL) {
+                value = "ALL";
+            } else if (this > 0) {
+                StringBuilder builder = new StringBuilder();
+                foreach (Field f in all()) {
+                    if (is_all_set(f)) {
+                        if (!String.is_empty(builder.str)) {
+                            builder.append(",");
+                        }
+                        builder.append(
+                            ObjectUtils.to_enum_nick(typeof(Field), f).up()
+                        );
+                    }
                 }
+                value = builder.str;
             }
-
-            return builder.str;
+            return value;
         }
     }
 
diff --git a/src/engine/imap-db/imap-db-folder.vala b/src/engine/imap-db/imap-db-folder.vala
index 615d8194..9b854173 100644
--- a/src/engine/imap-db/imap-db-folder.vala
+++ b/src/engine/imap-db/imap-db-folder.vala
@@ -1288,10 +1288,11 @@ private class Geary.ImapDB.Folder : BaseObject, Geary.ReferenceSemantics {
         int64 id = -1;
         // if fields not present, then no duplicate can reliably be found
         if (!email.fields.is_all_set(REQUIRED_FIELDS)) {
-            debug("%s: Unable to detect duplicates for %s, fields available: %s",
-                  this.to_string(),
-                  email.id.to_string(),
-                  email.fields.to_list_string()
+            debug(
+                "%s: Unable to detect duplicates for %s, fields available: %s",
+                this.to_string(),
+                email.id.to_string(),
+                email.fields.to_string()
             );
             return id;
         }
@@ -1304,8 +1305,11 @@ private class Geary.ImapDB.Folder : BaseObject, Geary.ReferenceSemantics {
         int64 rfc822_size = (imap_properties != null) ? imap_properties.rfc822_size.value : -1;
 
         if (String.is_empty(internaldate) || rfc822_size < 0) {
-            debug("Unable to detect duplicates for %s (%s available but invalid)", email.id.to_string(),
-                email.fields.to_list_string());
+            debug(
+                "Unable to detect duplicates for %s (%s available but invalid)",
+                email.id.to_string(),
+                email.fields.to_string()
+            );
             return id;
         }
 
diff --git a/src/engine/imap/api/imap-folder-session.vala b/src/engine/imap/api/imap-folder-session.vala
index c6d9a91b..00f48ca8 100644
--- a/src/engine/imap/api/imap-folder-session.vala
+++ b/src/engine/imap/api/imap-folder-session.vala
@@ -497,8 +497,11 @@ private class Geary.Imap.FolderSession : Geary.Imap.SessionObject {
                 out preview_charset_specifier
             );
             if (cmds.size == 0) {
-                throw new ImapError.INVALID("No FETCH commands generate for list request %s %s",
-                    msg_set.to_string(), fields.to_list_string());
+                throw new ImapError.INVALID(
+                    "No FETCH commands generate for list request %s %s",
+                    msg_set.to_string(),
+                    fields.to_string()
+                );
             }
 
             // Commands prepped, do the fetch and accumulate all the responses
@@ -549,9 +552,13 @@ private class Geary.Imap.FolderSession : Geary.Imap.SessionObject {
                         preview_charset_specifier
                     );
                     if (!email.fields.fulfills(fields)) {
-                        message("%s: %s missing=%s fetched=%s", to_string(), email.id.to_string(),
-                            fields.clear(email.fields).to_list_string(), fetched_data.to_string());
-
+                        message(
+                            "%s: %s missing=%s fetched=%s",
+                            to_string(),
+                            email.id.to_string(),
+                            fields.clear(email.fields).to_string(),
+                            fetched_data.to_string()
+                        );
                         continue;
                     }