From d333d0da74a6461d5a805c389cc35747293791b7 Mon Sep 17 00:00:00 2001
From: Damien Elmes <gpg@ankiweb.net>
Date: Thu, 19 Aug 2021 11:46:01 +1000
Subject: [PATCH] allow adjusting tag case in rename

https://forums.ankiweb.net/t/2-1-46-renaming-tags-to-tags-not-working/12426
---
 rslib/src/tags/register.rs | 18 ++++++++++--------
 rslib/src/tags/rename.rs   | 17 +++++++++++------
 2 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/rslib/src/tags/register.rs b/rslib/src/tags/register.rs
index 608a9622e..b2e902224 100644
--- a/rslib/src/tags/register.rs
+++ b/rslib/src/tags/register.rs
@@ -73,11 +73,7 @@ impl Collection {
     /// Create a tag object, normalize text, and match parents/existing case if available.
     /// True if tag is new.
     pub(super) fn prepare_tag_for_registering(&self, tag: &mut Tag) -> Result<bool> {
-        let normalized_name = normalize_tag_name(&tag.name);
-        if normalized_name.is_empty() {
-            // this should not be possible
-            return Err(AnkiError::invalid_input("blank tag"));
-        }
+        let normalized_name = normalize_tag_name(&tag.name)?;
         if let Some(existing_tag) = self.storage.get_tag(&normalized_name)? {
             tag.name = existing_tag.name;
             Ok(false)
@@ -99,7 +95,7 @@ impl Collection {
 
 impl Collection {
     /// If parent tag(s) exist and differ in case, return a rewritten tag.
-    fn adjusted_case_for_parents(&self, tag: &str) -> Result<Option<String>> {
+    pub(super) fn adjusted_case_for_parents(&self, tag: &str) -> Result<Option<String>> {
         if let Some(parent_tag) = self.first_existing_parent_tag(tag)? {
             let child_split: Vec<_> = tag.split("::").collect();
             let parent_count = parent_tag.matches("::").count() + 1;
@@ -144,8 +140,8 @@ fn normalized_tag_name_component(comp: &str) -> Cow<str> {
     }
 }
 
-fn normalize_tag_name(name: &str) -> Cow<str> {
-    if name
+pub(super) fn normalize_tag_name(name: &str) -> Result<Cow<str>> {
+    let normalized_name: Cow<str> = if name
         .split("::")
         .any(|comp| matches!(normalized_tag_name_component(comp), Cow::Owned(_)))
     {
@@ -157,6 +153,12 @@ fn normalize_tag_name(name: &str) -> Cow<str> {
     } else {
         // no changes required
         name.into()
+    };
+    if normalized_name.is_empty() {
+        // this should not be possible
+        Err(AnkiError::invalid_input("blank tag"))
+    } else {
+        Ok(normalized_name)
     }
 }
 
diff --git a/rslib/src/tags/rename.rs b/rslib/src/tags/rename.rs
index 0547d6190..3c427629b 100644
--- a/rslib/src/tags/rename.rs
+++ b/rslib/src/tags/rename.rs
@@ -1,8 +1,9 @@
 // Copyright: Ankitects Pty Ltd and contributors
 // License: GNU AGPL, version 3 or later; http://www.gnu.org/licenses/agpl.html
 
-use super::{is_tag_separator, matcher::TagMatcher, Tag};
+use super::{is_tag_separator, matcher::TagMatcher};
 use crate::prelude::*;
+use crate::tags::register::normalize_tag_name;
 
 impl Collection {
     /// Rename a given tag and its children on all notes that reference it, returning changed
@@ -29,10 +30,14 @@ impl Collection {
 
         let usn = self.usn()?;
 
-        // match existing case if available, and ensure normalized.
-        let mut tag = Tag::new(new_prefix.to_string(), usn);
-        self.prepare_tag_for_registering(&mut tag)?;
-        let new_prefix = &tag.name;
+        // ensure normalized+matching parent case, but not case of existing tag.
+        // The matching of parent case is mainly to be consistent with the way
+        // decks are handled.
+        let new_prefix = normalize_tag_name(new_prefix)?;
+        let new_prefix = self
+            .adjusted_case_for_parents(&new_prefix)?
+            .map(Into::into)
+            .unwrap_or(new_prefix);
 
         // gather tags that need replacing
         let mut re = TagMatcher::new(old_prefix)?;
@@ -53,7 +58,7 @@ impl Collection {
         // replace tags
         for mut note in matched_notes {
             let original = note.clone();
-            note.tags = re.replace(&note.tags, new_prefix);
+            note.tags = re.replace(&note.tags, &new_prefix);
             note.set_modified(usn);
             self.update_note_tags_undoable(&note, original)?;
         }