config: add default values for empty stylesets

When adding new style objects it is impossible to give them a default
color nor attributes without modifying each existing user styleset.
Also, if the user has an incomplete styleset, some parts of aerc will
have no style at all. These quirks are not nice from a user experience
point of view.

Before parsing the user styleset, initialize aerc style with basic
defaults. Reuse the exact same content than the actual "default"
styleset provided in /usr/share/aerc/stylesets. Comment all of the
default styleset to make it obvious that these are default values.

This has some implications:

* To reset these defaults, the user styleset must now start with these
  two lines:

    *.default = true
    *.normal = true

  If these two lines are not present, the default style will be kept and
  only changed if the user styleset explicitly sets them.

* Empty stylesets no longer produce weird results.

Signed-off-by: Robin Jarry <robin@jarry.cc>
Tested-by: Inwit <inwit@sindominio.net>

1 files changed, 9 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 20a1697f..05019a08 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -53,6 +53,15 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   default. Legacy behaviour can be restored by setting `send-with-hostname
   = true` in `accounts.conf`.
 - The notmuch bindings were replaced with internal bindings
+- Aerc now has a default style for most UI elements. The `default` styleset is
+  now empty. Existing stylesets will only override the default attributes if
+  they are set explicitly. To reset the default style and preserve existing
+  stylesets appearance, these two lines must be inserted **at the beginning**:
+
+  ```
+  *.default=true
+  *.normal=true
+  ```
 
 ### Deprecated