ID3v2: Fix single-value item conversions

Author: Serial-ATA

lofty/src/id3/v2/tag.rs

@@ -649,6 +649,10 @@ pub(super) fn new_text_frame<'a>(id: FrameId<'a>, value: impl Into<Cow<'a, str>>
 	Frame::Text(TextInformationFrame::new(id, TextEncoding::UTF8, value))
 }
 
+pub(super) fn new_url_frame<'a>(id: FrameId<'a>, value: impl Into<Cow<'a, str>>) -> Frame<'a> {
+	Frame::Url(UrlLinkFrame::new(id, value))
+}
+
 pub(super) fn new_user_text_frame<'a>(
 	description: impl Into<Cow<'a, str>>,
 	content: impl Into<Cow<'a, str>>,

lofty/src/id3/v2/tag/conversion.rs

@@ -13,7 +13,9 @@ use crate::tag::companion_tag::CompanionTag;
 use crate::tag::{Tag, TagItem, TagType};
 
 use super::V4_MULTI_VALUE_SEPARATOR;
-use crate::id3::v2::tag::{new_text_frame, new_timestamp_frame, new_user_text_frame};
+use crate::id3::v2::tag::{
+	new_text_frame, new_timestamp_frame, new_url_frame, new_user_text_frame,
+};
 use crate::id3::v2::util::mappings::TIPL_MAPPINGS;
 use crate::mp4::AdvisoryRating;
 use crate::tag::items::{Lang, Timestamp};
@@ -282,7 +284,7 @@ pub(crate) fn from_tag<'a>(
 			},
 
 			// TIPL key-value mappings
-			_ => {
+			_ if TIPL_MAPPINGS.iter().any(|(k, _)| *k == item_key) => {
 				let (_, tipl_key) = TIPL_MAPPINGS.iter().find(|(k, _)| *k == item_key)?;
 
 				let (value, _) = take_item_text_and_description(item)?;
@@ -293,6 +295,25 @@ pub(crate) fn from_tag<'a>(
 				// TIPL is collected at the end
 				None
 			},
+
+			// Anything else
+			_ => {
+				let Ok(id) = FrameId::try_from(item_key) else {
+					return None;
+				};
+
+				if id.as_str().starts_with('T') {
+					let (value, _) = take_item_text_and_description(item)?;
+					return Some(new_text_frame(id, value));
+				}
+
+				if id.as_str().starts_with('W') {
+					let (value, _) = take_item_text_and_description(item)?;
+					return Some(new_url_frame(id, value));
+				}
+
+				None
+			},
 		}
 	}
 

lofty/src/id3/v2/tag/tests.rs

@@ -1536,3 +1536,36 @@ fn multi_item_tag_dump() {
 	let artist_tag = tag.get_text(&FrameId::new("TPE1").unwrap()).unwrap();
 	assert_eq!(artist_tag, "Foo\0Bar");
 }
+
+#[test_log::test]
+fn single_value_frame() {
+	let mut tag = Tag::new(TagType::Id3v2);
+
+	// TBPM should be deduplicated during the conversion, taking whatever happens to be first
+	tag.push(TagItem::new(
+		ItemKey::IntegerBpm,
+		ItemValue::Text(String::from("120")),
+	));
+	tag.push(TagItem::new(
+		ItemKey::IntegerBpm,
+		ItemValue::Text(String::from("130")),
+	));
+	tag.push(TagItem::new(
+		ItemKey::IntegerBpm,
+		ItemValue::Text(String::from("140")),
+	));
+
+	let mut id3v2 = Vec::new();
+	tag.dump_to(&mut id3v2, WriteOptions::default()).unwrap();
+
+	let tag = read_tag_with_options(
+		&id3v2,
+		ParseOptions::new().parsing_mode(ParsingMode::Strict),
+	);
+
+	// The other BPM values were discarded, **NOT** merged
+	assert_eq!(tag.len(), 1);
+
+	let artist_tag = tag.get_text(&FrameId::new("TBPM").unwrap()).unwrap();
+	assert_eq!(artist_tag, "120");
+}