Make tags match their parents case

https://github.com/ankitects/anki/pull/900/#issuecomment-762018745

rslib/src/storage/tag/mod.rs

@@ -2,7 +2,8 @@
 // License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
 use super::SqliteStorage;
-use crate::{err::Result, tags::Tag, types::Usn};
+use crate::err::{AnkiError, Result};
+use crate::{tags::Tag, types::Usn};
 
 use rusqlite::{params, Row, NO_PARAMS};
 use std::collections::HashMap;
@@ -15,6 +16,10 @@ fn row_to_tag(row: &Row) -> Result<Tag> {
     })
 }
 
+fn immediate_parent_name(tag_name: &str) -> Option<&str> {
+    tag_name.rsplitn(2, "::").nth(1)
+}
+
 impl SqliteStorage {
     /// All tags in the collection, in alphabetical order.
     pub(crate) fn all_tags(&self) -> Result<Vec<Tag>> {
@@ -56,12 +61,43 @@ impl SqliteStorage {
         Ok(())
     }
 
-    pub(crate) fn preferred_tag_case(&self, tag: &str) -> Result<Option<String>> {
+    /// If parent tag(s) exist, rewrite name to match their case.
+    fn match_parents(&self, tag: &str) -> Result<String> {
+        let child_split: Vec<_> = tag.split("::").collect();
+        let t = if let Some(parent_tag) = self.first_existing_parent(&tag)? {
+            let parent_count = parent_tag.matches("::").count() + 1;
+            format!(
+                "{}::{}",
+                parent_tag,
+                &child_split[parent_count..].join("::")
+            )
+        } else {
+            tag.into()
+        };
+
+        Ok(t)
+    }
+
+    fn first_existing_parent(&self, mut tag: &str) -> Result<Option<String>> {
+        while let Some(parent_name) = immediate_parent_name(tag) {
+            if let Some(parent_tag) = self.get_tag(parent_name)? {
+                return Ok(Some(parent_tag.name));
+            }
+            tag = parent_name;
+        }
+
+        Ok(None)
+    }
+
+    // Get stored tag name or the same passed name if it doesn't exist, rewritten to match parents case.
+    // Returns a tuple of the preferred name and a boolean indicating if the tag exists.
+    pub(crate) fn preferred_tag_case(&self, tag: &str) -> Result<(Result<String>, bool)> {
         self.db
             .prepare_cached("select tag from tags where tag = ?")?
-            .query_and_then(params![tag], |row| row.get(0))?
-            .next()
-            .transpose()
+            .query_row(params![tag], |row| {
+                Ok((self.match_parents(row.get_raw(0).as_str()?), true))
+            })
+            .or_else::<AnkiError, _>(|_| Ok((self.match_parents(tag), false)))
             .map_err(Into::into)
     }
 

rslib/src/tags.rs

@@ -225,13 +225,13 @@ impl Collection {
         if normalized_name.is_empty() {
             return Ok((t, false));
         }
-        if let Some(preferred) = self.storage.preferred_tag_case(&normalized_name)? {
-            t.name = preferred;
-            Ok((t, false))
-        } else {
+        let (preferred, exists) = self.storage.preferred_tag_case(&normalized_name)?;
+        t.name = preferred?;
+        if !exists {
             self.storage.register_tag(&t)?;
-            Ok((t, true))
         }
+
+        Ok((t, !exists))
     }
 
     pub fn clear_unused_tags(&self) -> Result<()> {
@@ -533,6 +533,14 @@ mod test {
             )
         );
 
+        // children should match the case of their parents
+        col.storage.clear_tags()?;
+        *(&mut note.tags[0]) = "FOO".into();
+        *(&mut note.tags[1]) = "foo::BAR".into();
+        *(&mut note.tags[2]) = "foo::bar::baz".into();
+        col.update_note(&mut note)?;
+        assert_eq!(note.tags, vec!["FOO", "FOO::BAR", "FOO::BAR::baz"]);
+
         Ok(())
     }