M6: a radio group's XFA data compares every button's on state before any /PCOn

radio_dataset_value returned the first widget whose on state or /PCOn
equalled the selected state. With states /0 /1 and /PCOn items 1 2,
selecting /1 matched the first widget's /PCOn "1" and wrote 1 instead of
2, and strip_xfa's comparison, which uses the same function, could then
miss a lost value. The selection is an on-state name, so every widget's
state is now compared first and /PCOn only after.

Test (fails with the one-pass match restored, writing "1" for /1): the
static radio fixture with /PCOn 1 2 writes 1 for /0, 2 for /1, 2 for the
item 2, the value itself when nothing matches, and nothing with no
selection.

This changes the XFA data saved for such groups.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyCfwzyRXj4VfQAVVdv

crates/xfa/src/data/values.rs

@@ -60,21 +60,32 @@ pub fn radio_dataset_value(doc: &Document, f: &FieldDatum, sel: &Option<String>)
                 .collect()
         })
         .filter(|opt: &Vec<Option<String>>| opt.len() == kids.len());
-    for (i, kid) in kids.iter().enumerate() {
-        let Some(widget) = doc.resolve(kid).as_dict().cloned() else { continue };
-        let original = text_of(doc, &widget, b"PCOn");
-        let state = widget
-            .get(b"AP")
-            .map(|ap| doc.resolve(ap))
-            .and_then(|ap| ap.as_dict().and_then(|a| a.get(b"N").cloned()))
-            .and_then(|n| doc.resolve(&n).as_dict().cloned())
-            .and_then(|n| n.iter().map(|(k, _)| String::from_utf8_lossy(k).into_owned()).find(|k| k != "Off"));
-        if state.as_deref() == Some(selected) || original.as_deref() == Some(selected) {
+    // Each widget's (`/PCOn` item, on-state name, `/Opt` entry).
+    let widgets: Vec<(Option<String>, Option<String>, Option<String>)> = kids
+        .iter()
+        .enumerate()
+        .filter_map(|(i, kid)| {
+            let widget = doc.resolve(kid).as_dict().cloned()?;
+            let original = text_of(doc, &widget, b"PCOn");
+            let state = widget
+                .get(b"AP")
+                .map(|ap| doc.resolve(ap))
+                .and_then(|ap| ap.as_dict().and_then(|a| a.get(b"N").cloned()))
+                .and_then(|n| doc.resolve(&n).as_dict().cloned())
+                .and_then(|n| n.iter().map(|(k, _)| String::from_utf8_lossy(k).into_owned()).find(|k| k != "Off"));
             let export = exports.as_ref().and_then(|e| e.get(i).cloned().flatten());
-            return original.or(export).unwrap_or_else(|| selected.to_string());
-        }
+            Some((original, state, export))
+        })
+        .collect();
+    // `sel` is an on-state name, so every widget's state is compared before any `/PCOn`: with
+    // states `/0` `/1` and items `1` `2`, the state `1` is the second widget, not the first
+    // one's item.
+    let by_state = widgets.iter().find(|(_, state, _)| state.as_deref() == Some(selected));
+    let by_item = || widgets.iter().find(|(original, _, _)| original.as_deref() == Some(selected));
+    match by_state.or_else(by_item) {
+        Some((original, _, export)) => original.clone().or_else(|| export.clone()).unwrap_or_else(|| selected.to_string()),
+        None => selected.to_string(),
     }
-    selected.to_string()
 }
 
 /// The on and off item values of a check box (`/PCItems`), or the widget's on state.

crates/xfa/src/tests.rs

@@ -4145,3 +4145,21 @@ fn clear_password_values_clears_static_xfa_password_fields() {
     let packets = read_packets(&doc).unwrap().unwrap();
     assert!(!packets.xdp.contains("hunter2"), "{}", packets.xdp);
 }
+
+/// The data a radio group writes for its selected on state compares every button's state before
+/// any `/PCOn`: with states `/0` `/1` and `/PCOn` items `1` `2`, the state `1` is the second
+/// button, whose item is `2` (it used to match the first button's `/PCOn` `1` and write `1`).
+/// A selection that is only an item still finds its button.
+#[test]
+fn a_radio_state_is_matched_before_any_pcon_item() {
+    let doc = Document::open(Arc::new(crate::fixtures::static_radio_shell_with_pcon("<form1/>", ["1", "2"]))).unwrap();
+    let group = FieldDatum { obj: pdfcraft_cos::ObjRef::new(8, 0), name: "form1[0].page1[0].lang[0]".into(), data: FieldData::None };
+    let write = |sel: &str| crate::data::radio_dataset_value(&doc, &group, &Some(sel.to_string()));
+    assert_eq!(write("0"), "1");
+    assert_eq!(write("1"), "2");
+    // `2` is no state: it is the second button's item.
+    assert_eq!(write("2"), "2");
+    // Neither: written as given; nothing selected: empty.
+    assert_eq!(write("9"), "9");
+    assert_eq!(crate::data::radio_dataset_value(&doc, &group, &None), "");
+}