templates: unify data interface

Require that all aerc template data objects implement the same
TemplateData interface.

Implement that interface in two different places:

1) state.TemplateData (renamed/moved from templates.TemplateData).
   This structure (along with all its methods) needs to be decoupled
   from the templates package to break the import cycle with the config
   package. This allows much simpler construction of this object and
   ensure that values are calculated only when requested.

2) config.dummyData (extracted from templates).
   This is only used in the config package to validate user templates.
   Putting it here allows also to break an import cycle.

Use state.TemplateData everywhere (including for account tabs title
rendering).

Signed-off-by: Robin Jarry <robin@jarry.cc>
Reviewed-by: Moritz Poldrack <moritz@poldrack.dev>

1 files changed, 1 insertions, 3 deletions

diff --git a/config/columns.go b/config/columns.go
index b1c7191b..55efa2a7 100644
--- a/config/columns.go
+++ b/config/columns.go
@@ -90,9 +90,7 @@ func parseColumnDef(col string, section *ini.Section) (*ColumnDef, error) {
 		return nil, err
 	}
 
-	data := templates.DummyData()
-	var buf bytes.Buffer
-	err = t.Execute(&buf, data)
+	err = templates.Render(t, &bytes.Buffer{}, &dummyData{})
 	if err != nil {
 		return nil, err
 	}