From 7ad98ce9b81fa3b855ad26a75337c72f6b6873a2 Mon Sep 17 00:00:00 2001
From: dotCooCoo <RobertLeeLW@gmail.com>
Date: Sat, 14 Nov 2026 15:05:15 -0800
Subject: [PATCH] Perspective: a repeated id attaches, moves or transforms an
 object once

perspective.attach, perspective.release, perspective.move and
perspective.transform took their `ids` as given, so an id listed twice
was processed twice. Attach warped an object that was already projected
a second time, and a move or transform of an object not yet in
perspective attached it and then moved it twice. The Shift and Snap to
Grid reads of a move also used a document attached twice. The ids are
now taken once each, in the order first given.
---
 .../engine/src/cmd/distortcmds/perspective.rs |  7 ++++++-
 crates/engine/src/tests/distort.rs            | 21 ++++++++++++++++++-
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/crates/engine/src/cmd/distortcmds/perspective.rs b/crates/engine/src/cmd/distortcmds/perspective.rs
index 647f4a4342..90d58541a6 100644
--- a/crates/engine/src/cmd/distortcmds/perspective.rs
+++ b/crates/engine/src/cmd/distortcmds/perspective.rs
@@ -104,9 +104,14 @@ fn plane_param(g: &PerspectiveGrid, p: &Value, cmd: &str) -> Result<Plane> {
     Ok(plane)
 }
 
+/// The objects a perspective command acts on: the outermost of `ids` (each once, in the order first
+/// given), else the selection's roots.
 pub(super) fn roots(s: &Session, p: &Value) -> Result<Vec<NodeId>> {
     match named_ids(p)? {
-        Some(v) => Ok(outermost(&s.doc()?.doc, v)),
+        Some(v) => {
+            let mut seen = std::collections::HashSet::new();
+            Ok(outermost(&s.doc()?.doc, v.into_iter().filter(|id| seen.insert(*id)).collect()))
+        }
         None => selected_roots(s),
     }
 }
diff --git a/crates/engine/src/tests/distort.rs b/crates/engine/src/tests/distort.rs
index d033fadee6..6f56a09b68 100644
--- a/crates/engine/src/tests/distort.rs
+++ b/crates/engine/src/tests/distort.rs
@@ -1,6 +1,6 @@
 //! Width points, Liquify, Puppet Warp and Perspective Grid commands and tools.
 
-use serde_json::json;
+use serde_json::{Value, json};
 use vectorcraft_geom::{PathData, Point, Rect, Shape};
 use vectorcraft_tools::distort::perspective::{PerspectiveGrid, Plane};
 use vectorcraft_tools::{Mods, PointerEvent, PointerKind, ToolKey};
@@ -625,6 +625,25 @@ fn attach_projects_onto_the_plane_and_releases() {
     assert_eq!(path(&s, a).bounds().unwrap(), Rect::new(450.0, 300.0, 550.0, 400.0));
 }
 
+#[test]
+fn a_repeated_id_attaches_moves_and_transforms_an_object_once() {
+    let edited = |cmd: &str, ids: &[u64], extra: Value| {
+        let mut s = session();
+        s.execute("perspective.grid.preset", &json!({"kind": 2})).unwrap();
+        let a = rect(&mut s, 450.0, 300.0, 100.0, 100.0);
+        let ids: Vec<u64> = ids.iter().map(|_| a.0).collect();
+        let mut p = json!({"ids": ids, "plane": "right"});
+        p.as_object_mut().unwrap().extend(extra.as_object().unwrap().clone());
+        s.execute(cmd, &p).unwrap();
+        path(&s, a)
+    };
+    let moved = json!({"from": [480.0, 330.0], "to": [500.0, 350.0], "constrain": true});
+    let scaled = json!({"matrix": [1.5, 0.0, 0.0, 1.5, 10.0, 0.0]});
+    for (cmd, extra) in [("perspective.attach", json!({})), ("perspective.move", moved), ("perspective.transform", scaled)] {
+        assert_eq!(edited(cmd, &[0, 0], extra.clone()), edited(cmd, &[0], extra), "{cmd}");
+    }
+}
+
 #[test]
 fn rectangle_tool_draws_in_perspective_on_the_active_plane() {
     let mut s = session();