fix: discard changes was shown if note contained a newline

`<br>` in the collection was converted to `\n` in the
EditText, these weren't comparable

Fixes 20174

Author: david-allison

AnkiDroid/src/main/java/com/ichi2/anki/NoteEditorFragment.kt

@@ -149,6 +149,7 @@ import com.ichi2.anki.previewer.TemplatePreviewerArguments
 import com.ichi2.anki.previewer.TemplatePreviewerPage
 import com.ichi2.anki.servicelayer.LanguageHintService.languageHint
 import com.ichi2.anki.servicelayer.NoteService
+import com.ichi2.anki.servicelayer.NoteService.convertToHtmlNewline
 import com.ichi2.anki.snackbar.BaseSnackbarBuilderProvider
 import com.ichi2.anki.snackbar.SnackbarBuilder
 import com.ichi2.anki.snackbar.showSnackbar
@@ -1233,7 +1234,10 @@ class NoteEditorFragment :
         fun fieldsEdited(): Boolean {
             // Editing an existing note: Check to see if the fields are changed
             if (!addNote) {
-                return editFields!!.map { it.text?.toString() } != editorNote!!.fields.toList()
+                fun normalizeNewlines(s: String) = convertToHtmlNewline(s, replaceNewlines = true)
+                val currentStrings = editFields!!.map { it.text?.toString() ?: "" }
+                val originalStrings = editorNote!!.fields.toList()
+                return currentStrings.map(::normalizeNewlines) != originalStrings.map(::normalizeNewlines)
             }
 
             if (!isFieldEdited) return false

AnkiDroid/src/test/java/com/ichi2/anki/NoteEditorTest.kt

@@ -631,6 +631,32 @@ class NoteEditorTest : RobolectricTest() {
             }
         }
 
+    @Test
+    fun `hasUnsavedChanges - note is unchanged`() =
+        withNoteEditorEditing(addBasicNote("hello world")) {
+            this.setField(0, "hello world")
+            assertFalse(hasUnsavedChanges())
+        }
+
+    @Test
+    fun `hasUnsavedChanges - note is changed`() =
+        withNoteEditorEditing(addBasicNote("hello world")) {
+            this.setField(0, "hi")
+            assertTrue(hasUnsavedChanges())
+        }
+
+    @Test
+    fun `hasUnsavedChanges - note contained a newline`() =
+        withNoteEditorEditing(addBasicNote("hello\nworld")) {
+            assertFalse(hasUnsavedChanges())
+        }
+
+    @Test
+    fun `hasUnsavedChanges - note contained a HTML newline - 20174`() =
+        withNoteEditorEditing(addBasicNote("hello<br>world")) {
+            assertFalse(hasUnsavedChanges())
+        }
+
     private suspend fun withNoteEditorAdding(
         from: FromScreen = FromScreen.DECK_LIST,
         block: suspend NoteEditorFragment.() -> Unit,
@@ -639,6 +665,13 @@ class NoteEditorTest : RobolectricTest() {
         editor.block()
     }
 
+    private fun withNoteEditorEditing(
+        note: Note,
+        block: suspend NoteEditorFragment.() -> Unit,
+    ) = runTest {
+        block(getNoteEditorEditingExistingBasicNote(note, from = REVIEWER))
+    }
+
     private fun moveToDynamicDeck(note: Note): DeckId {
         val dyn = addDynamicDeck("All")
         col.decks.select(dyn)