M8: redaction removes the replies of the annotations it removes (#2659) (#2697)

* M8: redaction removes the replies of the annotations it removes (#2659)

A reply (/IRT) placed away from the mark survived, and its /IRT kept the
removed annotation - its comment text and the QuadPoints of the redacted
words - in the saved file. Replies to a removed annotation, and replies to
those, now go with it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RUNQSPVXx3dDBabRZHAnjz

* M8: test replies listed before their parent, with a pop-up on a reply (#2659)

Review of #2697: the replies precede the annotation they answer in
/Annots, deepest first, and a reply has a pop-up. A single pass in
/Annots order would keep them; the test fails with the loop cut to one
pass, which the first test does not notice.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RUNQSPVXx3dDBabRZHAnjz

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

crates/redact/README.md

@@ -25,7 +25,7 @@ clear_marks(&mut doc, None)?;                        // remove marks without app
 - **vectors**: covered paths are removed; partly covered paths and shadings are clipped so
   nothing paints inside the areas;
 - **form XObjects**: rewritten recursively into new objects (pages sharing the original keep it);
-- **annotations** whose rectangle overlaps (with their pop-ups), and **form fields** with a
+- **annotations** whose rectangle overlaps (with their pop-ups and their replies, `/IRT`), and **form fields** with a
   widget under a mark;
 - the marks themselves, replaced by boxes in their fill colour (and overlay text) drawn into the
   page as a `/PCMark /Redaction` stream.

crates/redact/src/lib.rs

@@ -455,6 +455,32 @@ pub fn apply(doc: &mut Document, pages: Option<&[usize]>) -> Result<Report, Reda
                 }
             }
         }
+        // Replies (`/IRT`, ISO 32000-2 §12.5.6.2) to a removed annotation go too, and replies to
+        // those: a reply placed elsewhere would keep its parent — the comment and the QuadPoints
+        // of the redacted words — in the file through its `/IRT` (#2659). Each pass removes at
+        // least one more annotation of this page or stops, so it ends.
+        let replies: Vec<(ObjRef, ObjRef)> = annots
+            .iter()
+            .filter_map(Object::as_ref)
+            .filter_map(|r| {
+                let obj = doc.get(r);
+                let d = obj.as_dict()?;
+                (d.name(b"Subtype") != Some(b"Widget")).then_some(())?;
+                Some((r, d.get(b"IRT").and_then(Object::as_ref)?))
+            })
+            .collect();
+        loop {
+            let before = removed.len();
+            for (r, parent) in &replies {
+                if !removed.contains(r) && removed.contains(parent) {
+                    removed.push(*r);
+                    report.annotations += 1;
+                }
+            }
+            if removed.len() == before {
+                break;
+            }
+        }
         let kept: Vec<Object> = annots
             .into_iter()
             .filter(|a| {

crates/redact/src/tests.rs

@@ -490,6 +490,59 @@ fn redacting_an_xfa_field_drops_the_xfa_packet_so_its_value_cannot_survive() {
     assert!(cat.get(b"NeedsRendering").is_none(), "/NeedsRendering is cleared");
 }
 
+#[test]
+fn replies_to_a_redacted_comment_go_with_it() {
+    // #2659: a highlight under the mark has a reply placed elsewhere, and that reply a reply of
+    // its own. The replies' /IRT would keep the highlight (its comment and QuadPoints) in the file.
+    let objs: Vec<Vec<u8>> = vec![
+        b"<< /Type /Catalog /Pages 2 0 R >>".to_vec(),
+        b"<< /Type /Pages /Kids [3 0 R] /Count 1 >>".to_vec(),
+        b"<< /Type /Page /Parent 2 0 R /MediaBox [0 0 300 300] /Contents 4 0 R /Annots [5 0 R 6 0 R 7 0 R 8 0 R] >>".to_vec(),
+        stream("", b"BT ET"),
+        b"<< /Type /Annot /Subtype /Highlight /Rect [20 20 60 30] /QuadPoints [20 30 60 30 20 20 60 20] /Contents (HIGHLIGHT-NOTE) >>".to_vec(),
+        b"<< /Type /Annot /Subtype /Text /Rect [250 250 270 270] /IRT 5 0 R /Contents (FIRST-REPLY) >>".to_vec(),
+        b"<< /Type /Annot /Subtype /Text /Rect [250 200 270 220] /IRT 6 0 R /Contents (SECOND-REPLY) >>".to_vec(),
+        b"<< /Type /Annot /Subtype /Text /Rect [250 100 270 120] /Contents (UNRELATED) >>".to_vec(),
+    ];
+    let mut doc = pdf(objs);
+    mark(&mut doc, 0, &[[10.0, 10.0, 70.0, 40.0]], "");
+    let r = apply(&mut doc, None).unwrap();
+    assert_eq!(r.annotations, 3, "the highlight and both replies: {r:?}");
+    let p = pdfcraft_model::pages(&doc).swap_remove(0);
+    assert_eq!(annots_of(&doc, &p.dict).len(), 1, "only the unrelated note stays");
+    // A classic table, so the objects' strings are plain in the file.
+    let bytes = write_full(&doc, &SaveOptions { object_streams: false, ..SaveOptions::default() }).unwrap();
+    for gone in [&b"HIGHLIGHT-NOTE"[..], b"FIRST-REPLY", b"SECOND-REPLY"] {
+        assert!(!bytes.windows(gone.len()).any(|w| w == gone), "{} survived the save", String::from_utf8_lossy(gone));
+    }
+    assert!(bytes.windows(9).any(|w| w == b"UNRELATED"));
+}
+
+/// The replies listed before the annotations they answer, deepest first, and a pop-up on a
+/// reply: one pass in `/Annots` order would keep them, the repeated passes don't (review of
+/// #2697).
+#[test]
+fn replies_listed_before_their_parent_and_their_pop_ups_go_too() {
+    let objs: Vec<Vec<u8>> = vec![
+        b"<< /Type /Catalog /Pages 2 0 R >>".to_vec(),
+        b"<< /Type /Pages /Kids [3 0 R] /Count 1 >>".to_vec(),
+        b"<< /Type /Page /Parent 2 0 R /MediaBox [0 0 300 300] /Contents 4 0 R /Annots [7 0 R 9 0 R 6 0 R 5 0 R 8 0 R] >>".to_vec(),
+        stream("", b"BT ET"),
+        b"<< /Type /Annot /Subtype /Highlight /Rect [20 20 60 30] /QuadPoints [20 30 60 30 20 20 60 20] /Contents (HIGHLIGHT-NOTE) >>".to_vec(),
+        b"<< /Type /Annot /Subtype /Text /Rect [250 250 270 270] /IRT 5 0 R /Contents (FIRST-REPLY) /Popup 9 0 R >>".to_vec(),
+        b"<< /Type /Annot /Subtype /Text /Rect [250 200 270 220] /IRT 6 0 R /Contents (SECOND-REPLY) >>".to_vec(),
+        b"<< /Type /Annot /Subtype /Text /Rect [250 100 270 120] /Contents (UNRELATED) >>".to_vec(),
+        b"<< /Type /Annot /Subtype /Popup /Rect [200 150 290 190] /Parent 6 0 R >>".to_vec(),
+    ];
+    let mut doc = pdf(objs);
+    mark(&mut doc, 0, &[[10.0, 10.0, 70.0, 40.0]], "");
+    let r = apply(&mut doc, None).unwrap();
+    assert_eq!(r.annotations, 3, "the highlight and both replies: {r:?}");
+    let p = pdfcraft_model::pages(&doc).swap_remove(0);
+    let left = annots_of(&doc, &p.dict);
+    assert_eq!(left, vec![Object::Ref(ObjRef::new(8, 0))], "only the unrelated note stays, the reply's pop-up goes too");
+}
+
 #[test]
 fn comments_links_and_fields_under_a_mark_go() {
     let mut doc = one_page(b"", "", vec![]);

parity/acrobat-features.toml

@@ -5728,8 +5728,8 @@ milestone = "M8"
 status = "shipped"
 commands = ["redact.apply"]
 tools = ["redact_apply"]
-evidence = ["crates/redact/src/tests.rs::comments_links_and_fields_under_a_mark_go", "crates/ui-egui/tests/ui_group/redact.rs::marking_applying_and_clearing"]
-notes = "with pop-ups; fields lose all widgets"
+evidence = ["crates/redact/src/tests.rs::comments_links_and_fields_under_a_mark_go", "crates/redact/src/tests.rs::replies_to_a_redacted_comment_go_with_it", "crates/ui-egui/tests/ui_group/redact.rs::marking_applying_and_clearing"]
+notes = "with pop-ups and replies (/IRT, transitively; replies on other pages are not followed); fields lose all widgets"
 
 [[feature]]
 id = "protect.redact-struct-tree"