Fix CDATA decoding in worksheet text

.github/workflows/rust.yml

@@ -2,9 +2,9 @@ name: umya-spreadsheet
 
 on:
   push:
-    branches: ["*"]
+    branches: ["**"]
   pull_request:
-    branches: ["*"]
+    branches: ["**"]
 
 env:
   CARGO_TERM_COLOR: always

src/helper/utils.rs

@@ -15,14 +15,35 @@ macro_rules! from_err {
 /// quick-xml reports references as separate `GeneralRef` events, so a text
 /// event alone would read `R&D` as `R` and `D`. Readers take the raw
 /// element content with `Reader::read_text_into` and unescape it here.
-/// Malformed input keeps the raw text instead of panicking.
+/// CDATA content stays literal; malformed spans keep their raw text.
 pub(crate) fn unescape_xml_text(e: &quick_xml::events::BytesText<'_>) -> String {
     let decoded = match e.decode() {
         Ok(decoded) => decoded,
         Err(_) => String::from_utf8_lossy(e),
     };
-    match quick_xml::escape::unescape(&decoded) {
-        Ok(unescaped) => unescaped.into_owned(),
-        Err(_) => decoded.into_owned(),
+    let mut remaining = decoded.as_ref();
+    let mut output = String::with_capacity(remaining.len());
+    while let Some(start) = remaining.find("<![CDATA[") {
+        let prefix = &remaining[..start];
+        output.push_str(&quick_xml::escape::unescape(prefix).unwrap_or(prefix.into()));
+        let content = &remaining[start + 9..];
+        let Some(end) = content.find("]]>") else {
+            return decoded.into_owned();
+        };
+        output.push_str(&content[..end]);
+        remaining = &content[end + 3..];
+    }
+    output.push_str(&quick_xml::escape::unescape(remaining).unwrap_or(remaining.into()));
+    output
+}
+
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn malformed_text_keeps_the_existing_tolerant_behavior() {
+        for text in ["R&broken", "<![CDATA[unfinished", "before &unknown; after"] {
+            let raw = quick_xml::events::BytesText::from_escaped(text);
+            assert_eq!(super::unescape_xml_text(&raw), text);
+        }
     }
 }

tests/cdata_text.rs

@@ -0,0 +1,76 @@
+use std::io::{Cursor, Read, Write};
+
+use umya_spreadsheet::{reader, writer};
+use zip::{write::SimpleFileOptions, ZipArchive, ZipWriter};
+
+fn workbook_with_header_text(content: &str) -> Vec<u8> {
+    let mut book = umya_spreadsheet::new_file();
+    let sheet = book.get_sheet_mut(&0).unwrap();
+    sheet.get_cell_mut("A1").set_value("CDATA regression");
+    sheet
+        .get_header_footer_mut()
+        .get_odd_header_mut()
+        .set_value("HEADER_PLACEHOLDER");
+    sheet
+        .get_header_footer_mut()
+        .get_odd_footer_mut()
+        .set_value("FOOTER_PLACEHOLDER");
+    let mut original = Vec::new();
+    writer::xlsx::write_writer(&book, &mut original).unwrap();
+    let mut source = ZipArchive::new(Cursor::new(original)).unwrap();
+    let mut output = ZipWriter::new(Cursor::new(Vec::new()));
+    for index in 0..source.len() {
+        let mut part = source.by_index(index).unwrap();
+        let mut bytes = Vec::new();
+        part.read_to_end(&mut bytes).unwrap();
+        if part.name() == "xl/worksheets/sheet1.xml" {
+            bytes = String::from_utf8(bytes)
+                .unwrap()
+                .replace("HEADER_PLACEHOLDER", content)
+                .replace("FOOTER_PLACEHOLDER", content)
+                .into_bytes();
+        }
+        output
+            .start_file(part.name(), SimpleFileOptions::default())
+            .unwrap();
+        output.write_all(&bytes).unwrap();
+    }
+    output.finish().unwrap().into_inner()
+}
+
+#[test]
+fn header_footer_text_preserves_cdata_and_decodes_only_outside_entities() {
+    for (xml, expected) in [
+        (
+            "&amp;CResearch &amp; Development",
+            "&CResearch & Development",
+        ),
+        (
+            "<![CDATA[&C&BResearch & Development&B]]>",
+            "&C&BResearch & Development&B",
+        ),
+        (
+            "&amp;LBefore <![CDATA[&amp; literal <tag>]]> &#65;<![CDATA[&Rafter]]>",
+            "&LBefore &amp; literal <tag> A&Rafter",
+        ),
+        (
+            "<![CDATA[]]>&amp;C<![CDATA[One]]><![CDATA[Two]]>",
+            "&COneTwo",
+        ),
+        ("&lt;![CDATA[ordinary]]&gt;", "<![CDATA[ordinary]]>"),
+    ] {
+        let bytes = workbook_with_header_text(xml);
+        let book = reader::xlsx::read_reader(Cursor::new(bytes), true).unwrap();
+        let header_footer = book.get_sheet(&0).unwrap().get_header_footer();
+        assert_eq!(
+            header_footer.get_odd_header().get_value(),
+            expected,
+            "{xml}"
+        );
+        assert_eq!(
+            header_footer.get_odd_footer().get_value(),
+            expected,
+            "{xml}"
+        );
+    }
+}