Add details to TemplateSaveError

ftl/core/card-templates.ftl

@@ -21,6 +21,7 @@ card-templates-night-mode = Night Mode
 card-templates-add-mobile-class = Add Mobile Class
 card-templates-preview-settings = Options
 card-templates-invalid-template-number = Card template { $number } in notetype '{ $notetype }' has a problem.
+card-templates-see-preview = See the render preview for more information.
 card-templates-changes-saved = Changes saved.
 card-templates-discard-changes = Discard changes?
 card-templates-add-card-type = Add Card Type...

rslib/src/error/mod.rs

@@ -61,9 +61,14 @@ impl AnkiError {
                 // already localized
                 info.into()
             }
-            AnkiError::TemplateSaveError(err) => tr
-                .card_templates_invalid_template_number(err.ordinal + 1, &err.notetype)
-                .into(),
+            AnkiError::TemplateSaveError(err) => {
+                let header =
+                    tr.card_templates_invalid_template_number(err.ordinal + 1, &err.notetype);
+                let details = match err.details {
+                    TemplateSaveErrorDetails::TemplateError => tr.card_templates_see_preview(),
+                };
+                format!("{}<br>{}", header, details)
+            }
             AnkiError::DbError(err) => err.localized_description(tr),
             AnkiError::SearchError(kind) => kind.localized_description(&tr),
             AnkiError::InvalidInput(info) => {
@@ -135,4 +140,10 @@ impl From<regex::Error> for AnkiError {
 pub struct TemplateSaveError {
     pub notetype: String,
     pub ordinal: usize,
+    pub details: TemplateSaveErrorDetails,
+}
+
+#[derive(Debug, PartialEq)]
+pub enum TemplateSaveErrorDetails {
+    TemplateError,
 }

rslib/src/notetype/mod.rs

@@ -37,7 +37,7 @@ pub use crate::backend_proto::{
 };
 use crate::{
     define_newtype,
-    error::TemplateSaveError,
+    error::{TemplateSaveError, TemplateSaveErrorDetails},
     prelude::*,
     template::{FieldRequirements, ParsedTemplate},
     text::ensure_string_in_nfc,
@@ -330,6 +330,7 @@ impl Notetype {
             return Err(AnkiError::TemplateSaveError(TemplateSaveError {
                 notetype: self.name.clone(),
                 ordinal: idx,
+                details: TemplateSaveErrorDetails::TemplateError,
             }));
         }
         let reqs = self.updated_requirements(&parsed_templates);