M5: group selection goes through the page router's one look at the point (#4358)

main now checks that only listed functions ask which comment lies under a
point. The group lookup is `click_target` (a subordinate stands for its
primary, ISO 32000-2 12.5.6.2), listed with `picked`; a right-click acts on
the comment the router already found instead of looking again.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyDBXygTf7jcqdsjcfn

crates/ui-egui/src/canvas/page_pointer/tests.rs

@@ -559,9 +559,14 @@ const PAGE_HITS_ASKERS: [(&str, &str, &str); 5] = [
 const COMMENT_POINT_TESTS: [&str; 2] = [".comment_at(", "PageCx::comment_at("];
 
 /// The functions that ask which comment lies under a point: (file, function, why).
-const COMMENT_POINT_TESTERS: [(&str, &str, &str); 3] = [
+const COMMENT_POINT_TESTERS: [(&str, &str, &str); 4] = [
     ("tools/comments/input.rs", "hit", "the comments' hit test"),
-    ("tools/comments/input.rs", "context_hit", "the comments' hit test for a right-click"),
+    (
+        "tools/comments/state.rs",
+        "click_target",
+        "the comments' hit tests' lookup: a group subordinate (`/RT /Group`, ISO 32000-2 §12.5.6.2) stands for its primary",
+    ),
+    ("tools/comments/state.rs", "picked", "which group subordinate a click selected its primary through, when the click is acted on"),
     ("tools/comments/paint.rs", "paint_page", "a redaction mark shows its fill under the pointer with every tool, as comments' tips show"),
 ];
 

crates/ui-egui/src/tools/comments/input.rs

@@ -103,7 +103,7 @@ pub(crate) fn hit(cx: &PageCx<'_>, view: &DocView, p: Pos2, on_link: bool) -> Op
     // there selects the group. Only a click: a drag still moves what is under the pointer.
     let (a, member) = match cx.comment_at(p) {
         Some(a) => (a, false),
-        None => (cx.click_hit(p)?, true),
+        None => (cx.click_target(p)?, true),
     };
     let a = Some(a).filter(|a| bodies && pick(a))?;
     // A click on a highlight over a link follows the link, so the link's hand and tip show there.
@@ -131,7 +131,7 @@ pub(crate) fn context_hit(cx: &PageCx<'_>, p: Pos2) -> Option<Hit> {
     if cx.hidden || !cx.xf.rect.contains(p) {
         return None;
     }
-    let a = cx.click_hit(p)?;
+    let a = cx.click_target(p)?;
     Some(Hit::new(Owner::Comment { index: a.index, part: CommentPart::Body }, layer(a), egui::CursorIcon::Default))
 }
 
@@ -146,7 +146,8 @@ pub(crate) fn anchor(cx: &PageCx<'_>, p: Pos2, view: &mut DocView) {
 /// anything else selects none.
 pub(crate) fn context(cx: &PageCx<'_>, p: Pos2, index: Option<usize>, view: &mut DocView) {
     match index {
-        Some(i) => match cx.click_hit(p).filter(|a| a.index == i) {
+        // `index` is what the right-click is on ([`context_hit`]): no second look at the point.
+        Some(i) => match cx.get(i) {
             Some(a) => view.comments.pick(cx, p, a),
             None => view.comments.select(Some((cx.page, i))),
         },

crates/ui-egui/src/tools/comments/state.rs

@@ -208,7 +208,7 @@ impl CommentView {
         self.member = None;
     }
 
-    /// Select `a`, the comment a press at `p` on this page selects ([`PageCx::click_hit`]),
+    /// Select `a`, the comment a press at `p` on this page selects ([`PageCx::click_target`]),
     /// remembering the group subordinate under `p` when `a` is its group's primary
     /// ([`PageCx::picked`]). The only place that sets [`Self::member`].
     pub(crate) fn pick(&mut self, cx: &PageCx<'_>, p: Pos2, a: &Annotation) {
@@ -439,7 +439,7 @@ impl PageCx<'_> {
 
     /// The comment a click at `p` selects: the topmost one under it or, on a group subordinate,
     /// the group's primary, which stands for the group.
-    pub(super) fn click_hit(&self, p: Pos2) -> Option<&Annotation> {
+    pub(super) fn click_target(&self, p: Pos2) -> Option<&Annotation> {
         self.comment_at(p).or_else(|| self.member_at(p).map(|(_, p)| p))
     }