feat: support middle-click paste in text fields (#60)

Selecting an nsec in another Linux application and middle-clicking Coop's identity import field currently does nothing. The shared input widget handles left and right clicks but never reads the primary selection for a middle click.

Add middle-click paste from PRIMARY on Linux and FreeBSD, inserting at the nearest visible caret to the click. Read the selection before changing focus, preserve disabled/read-only inputs, strip line breaks in single-line fields, and use the input state's atomic insertion path so Undo removes the paste. Also register Shift+Insert for standard clipboard paste on non-macOS platforms. The existing right-click editing menu and Ctrl+V/Cmd+V remain available.

Document the gestures in the README. Enable GPUI test support for the UI crate; the lockfile additions are its test dependencies.

Validation:

- `cargo check -p ui --locked`
- `cargo test -p ui --lib --locked` — all five tests pass, including empty-field paste, Unicode caret placement, primary/clipboard separation, Undo, and disabled/read-only protection
- `git -c core.whitespace=cr-at-eol diff --check` (preserves the existing CRLF Cargo manifest)

Validated with GPUI's simulated input and clipboard platform; no live X11/Wayland compositor test was performed.

Release Notes:

- Fixed middle-click paste in Linux text fields, including identity import, and added Shift+Insert clipboard paste.

Reviewed-on: reya/coop#60
Co-authored-by: Vincent Bernardoff <vb@luminar.eu.org>

Cargo.lock

@@ -674,15 +674,30 @@ dependencies = [
  "unicode-normalization",
 ]
 
+[[package]]
+name = "bit-set"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "08807e080ed7f9d5433fa9b275196cfc35414f66a0c79d864dc51a0d825231a3"
+dependencies = [
+ "bit-vec 0.8.0",
+]
+
 [[package]]
 name = "bit-set"
 version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "34ddef2995421ab6a5c779542c81ee77c115206f4ad9d5a8e05f4ff49716a3dd"
 dependencies = [
- "bit-vec",
+ "bit-vec 0.9.1",
 ]
 
+[[package]]
+name = "bit-vec"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5e764a1d40d510daf35e07be9eb06e75770908c27d411ee6c92109c9840eaaf7"
+
 [[package]]
 name = "bit-vec"
 version = "0.9.1"
@@ -1362,6 +1377,15 @@ dependencies = [
  "unicode-segmentation",
 ]
 
+[[package]]
+name = "convert_case"
+version = "0.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "affbf0190ed2caf063e3def54ff444b449371d55c58e513a95ab98eca50adb49"
+dependencies = [
+ "unicode-segmentation",
+]
+
 [[package]]
 name = "cookie"
 version = "0.18.2"
@@ -1798,7 +1822,7 @@ version = "2.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "799a97264921d8623a957f6c3b9011f3b5492f557bbb7a5a19b7fa6d06ba8dcb"
 dependencies = [
- "convert_case",
+ "convert_case 0.10.0",
  "proc-macro2",
  "quote",
  "rustc_version",
@@ -2758,6 +2782,7 @@ dependencies = [
  "pollster 0.4.0",
  "postage",
  "profiling",
+ "proptest",
  "rand 0.9.5",
  "raw-window-handle",
  "regex",
@@ -3775,7 +3800,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "525e9ff3e1a4be2fbea1fdf0e98686a6d98b4d8f937e1bf7402245af1909e8c3"
 dependencies = [
  "byteorder-lite",
- "quick-error",
+ "quick-error 2.0.1",
 ]
 
 [[package]]
@@ -4463,7 +4488,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b2bf919621e7975acb27d881bae2fb993e0d45c8e0446e85e6272971e00dc8df"
 dependencies = [
  "arrayvec",
- "bit-set",
+ "bit-set 0.9.1",
  "bitflags 2.13.2",
  "cfg-if",
  "cfg_aliases",
@@ -5814,6 +5839,38 @@ dependencies = [
  "syn 2.0.119",
 ]
 
+[[package]]
+name = "proptest"
+version = "1.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b45fcc2344c680f5025fe57779faef368840d0bd1f42f216291f0dc4ace4744"
+dependencies = [
+ "bit-set 0.8.0",
+ "bit-vec 0.8.0",
+ "bitflags 2.13.2",
+ "num-traits",
+ "proptest-macro",
+ "rand 0.9.5",
+ "rand_chacha 0.9.0",
+ "rand_xorshift",
+ "regex-syntax",
+ "rusty-fork",
+ "tempfile",
+ "unarray",
+]
+
+[[package]]
+name = "proptest-macro"
+version = "0.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "efaa288b896cb2b345da7b7f2110ab19e51565b83495b56fcec98a62f8b1f33e"
+dependencies = [
+ "convert_case 0.11.0",
+ "proc-macro2",
+ "quote",
+ "syn 2.0.119",
+]
+
 [[package]]
 name = "pulp"
 version = "0.22.3"
@@ -5852,6 +5909,12 @@ dependencies = [
  "bytemuck",
 ]
 
+[[package]]
+name = "quick-error"
+version = "1.2.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1d01941d82fa2ab50be1e79e6714289dd7cde78eba4c074bc5a4374f650dfe0"
+
 [[package]]
 name = "quick-error"
 version = "2.0.1"
@@ -6029,6 +6092,15 @@ dependencies = [
  "rand_core 0.10.1",
 ]
 
+[[package]]
+name = "rand_xorshift"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "513962919efc330f829edb2535844d1b912b0fbe2ca165d613e4e8788bb05a5a"
+dependencies = [
+ "rand_core 0.9.5",
+]
+
 [[package]]
 name = "range-alloc"
 version = "0.1.5"
@@ -6085,7 +6157,7 @@ dependencies = [
  "avif-serialize",
  "imgref",
  "loop9",
- "quick-error",
+ "quick-error 2.0.1",
  "rav1e",
  "rayon",
  "rgb",
@@ -6512,6 +6584,18 @@ version = "1.0.23"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf54715a573b99ac80df0bc206da022bcd442c974952c7b9720069370852e21f"
 
+[[package]]
+name = "rusty-fork"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cc6bf79ff24e648f6da1f8d1f011e9cac26491b619e6b9280f2b47f1774e6ee2"
+dependencies = [
+ "fnv",
+ "quick-error 1.2.3",
+ "tempfile",
+ "wait-timeout",
+]
+
 [[package]]
 name = "rustybuzz"
 version = "0.20.1"
@@ -7503,7 +7587,7 @@ dependencies = [
  "fax",
  "flate2",
  "half",
- "quick-error",
+ "quick-error 2.0.1",
  "weezl",
  "zune-jpeg",
 ]
@@ -7964,6 +8048,12 @@ dependencies = [
  "uuid",
 ]
 
+[[package]]
+name = "unarray"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "eaea85b334db583fe3274d12b4cd1880032beab409c0d774be044d4480ab9a94"
+
 [[package]]
 name = "unicase"
 version = "2.10.0"
@@ -8260,6 +8350,15 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "wait-timeout"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "09ac3b126d3914f9849036f826e054cbabdc8519970b8998ddaf3b5bd3c65f11"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "waker-fn"
 version = "1.2.0"
@@ -8586,8 +8685,8 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2f519832254e56965a9940c4af57dcb75f702b6f6fa4a0b172f685395843a4d7"
 dependencies = [
  "arrayvec",
- "bit-set",
+ "bit-set 0.9.1",
- "bit-vec",
+ "bit-vec 0.9.1",
  "bitflags 2.13.2",
  "bytemuck",
  "cfg_aliases",
@@ -8658,7 +8757,7 @@ dependencies = [
  "android_system_properties",
  "arrayvec",
  "ash",
- "bit-set",
+ "bit-set 0.9.1",
  "bitflags 2.13.2",
  "block2 0.6.2",
  "bytemuck",

README.md

@@ -1,5 +1,13 @@
 Coop is a simple, fast, and reliable nostr client for secure messaging across all platforms.
 
+### Pasting into text fields
+
+Click a field and use Ctrl+V (Cmd+V on macOS), or right-click and choose Paste.
+Shift+Insert also pastes from the clipboard on Linux and Windows. On Linux,
+middle-click inserts the primary selection at the clicked position: select text
+in another application first, then middle-click the field. This also works in
+the identity import dialog.
+
 ### License
 
 Copyright (C) 2025 Ren Amamiya & other Coop contributors

crates/ui/Cargo.toml

@@ -14,3 +14,6 @@ serde.workspace = true
 smallvec.workspace = true
 
 uuid = "1.10"
+
+[dev-dependencies]
+gpui = { workspace = true, features = ["test-support"] }

crates/ui/src/input/input.rs

@@ -13,6 +13,35 @@ use crate::indicator::Indicator;
 use crate::input::clear_button;
 use crate::{IconName, Selectable, Sizable, Size, StyleSized, StyledExt, h_flex, v_flex};
 
+#[cfg(any(target_os = "linux", target_os = "freebsd"))]
+fn primary_paste_offset(
+    value: &str,
+    position: gpui::Point<Pixels>,
+    mut caret_bounds: impl FnMut(usize) -> Option<gpui::Bounds<Pixels>>,
+) -> Option<usize> {
+    value
+        .char_indices()
+        .map(|(offset, _)| offset)
+        .chain(std::iter::once(value.len()))
+        .filter_map(|offset| {
+            let bounds = caret_bounds(offset)?;
+            let vertical_distance = if position.y < bounds.top() {
+                bounds.top() - position.y
+            } else if position.y > bounds.bottom() {
+                position.y - bounds.bottom()
+            } else {
+                px(0.)
+            };
+            Some((
+                offset,
+                vertical_distance,
+                (position.x - bounds.left()).abs(),
+            ))
+        })
+        .min_by(|left, right| left.1.cmp(&right.1).then_with(|| left.2.cmp(&right.2)))
+        .map(|(offset, _, _)| offset)
+}
+
 /// The background of an input frame, which reads muted while the input is disabled.
 fn input_background(disabled: bool, cx: &App) -> Hsla {
     if disabled {
@@ -225,6 +254,45 @@ impl<M: InputModeKind> RenderOnce for Input<M> {
                 let state_entity = state_entity.clone();
                 move |_, window, cx| state_entity.update(cx, |state, cx| state.focus(window, cx))
             })
+            .when(
+                cfg!(any(target_os = "linux", target_os = "freebsd")),
+                |this| {
+                    #[cfg(any(target_os = "linux", target_os = "freebsd"))]
+                    let this = this.on_mouse_down(MouseButton::Middle, {
+                        let state_entity = state_entity.clone();
+                        move |event, window, cx| {
+                            if disabled || !state_entity.read(cx).is_editable() {
+                                return;
+                            }
+                            // Read before changing focus or selection: those can change PRIMARY.
+                            let Some(text) = cx.read_from_primary().and_then(|item| item.text())
+                            else {
+                                return;
+                            };
+                            state_entity.update(cx, |state, cx| {
+                                let value = state.value();
+                                let Some(offset) =
+                                    primary_paste_offset(&value, event.position, |offset| {
+                                        state.range_to_bounds(&(offset..offset))
+                                    })
+                                else {
+                                    return;
+                                };
+                                let text = if state.is_multi_line() {
+                                    text
+                                } else {
+                                    text.replace(['\r', '\n'], "")
+                                };
+                                state.focus(window, cx);
+                                state.set_selected_range(offset..offset, cx);
+                                state.insert(text, window, cx);
+                            });
+                            cx.stop_propagation();
+                        }
+                    });
+                    this
+                },
+            )
             .items_center()
             .when(multi_line, |this| {
                 this.h_auto()
@@ -273,3 +341,167 @@ impl<M: InputModeKind> RenderOnce for Input<M> {
             })
     }
 }
+
+#[cfg(all(test, any(target_os = "linux", target_os = "freebsd")))]
+mod tests {
+    use super::*;
+    use crate::input::InputState;
+    use gpui::{AppContext, ClipboardItem, Context, Render, TestAppContext, point};
+
+    struct TestInput {
+        input: Entity<InputState>,
+        disabled: bool,
+    }
+
+    impl Render for TestInput {
+        fn render(&mut self, _: &mut Window, _: &mut Context<Self>) -> impl IntoElement {
+            div()
+                .w(px(300.))
+                .h(px(40.))
+                .child(Input::new(&self.input).disabled(self.disabled))
+        }
+    }
+
+    #[gpui::test]
+    fn middle_click_pastes_primary_at_clicked_position(cx: &mut TestAppContext) {
+        cx.update(|cx| {
+            theme::init(cx);
+            crate::init(cx);
+        });
+        let (view, cx) = cx.add_window_view(|window, cx| TestInput {
+            input: cx.new(|cx| InputState::new(window, cx).default_value("aéz")),
+            disabled: false,
+        });
+        let input = view.read_with(cx, |view, _| view.input.clone());
+        cx.update(|window, cx| {
+            window.draw(cx).clear(cx);
+            cx.write_to_clipboard(ClipboardItem::new_string("wrong clipboard".into()));
+            cx.write_to_primary(ClipboardItem::new_string("nsec1test\r\n".into()));
+        });
+        let position = input.read_with(cx, |state, _| {
+            state.range_to_bounds(&(3..3)).map(|bounds| bounds.center())
+        });
+        assert!(position.is_some());
+        if let Some(position) = position {
+            cx.simulate_mouse_down(position, MouseButton::Middle, Default::default());
+            cx.simulate_mouse_up(position, MouseButton::Middle, Default::default());
+        }
+        assert_eq!(
+            input.read_with(cx, |state, _| state.value()),
+            "aénsec1testz"
+        );
+
+        cx.update(|window, cx| {
+            window.dispatch_action(Box::new(gpui_base::input::Undo), cx);
+        });
+        assert_eq!(input.read_with(cx, |state, _| state.value()), "aéz");
+
+        cx.update(|window, cx| {
+            input.update(cx, |state, cx| state.set_value("", window, cx));
+            window.draw(cx).clear(cx);
+        });
+        cx.simulate_mouse_down(
+            point(px(200.), px(20.)),
+            MouseButton::Middle,
+            Default::default(),
+        );
+        cx.simulate_mouse_up(
+            point(px(200.), px(20.)),
+            MouseButton::Middle,
+            Default::default(),
+        );
+        assert_eq!(input.read_with(cx, |state, _| state.value()), "nsec1test");
+    }
+
+    #[gpui::test]
+    fn clipboard_shortcuts_paste_without_using_primary(cx: &mut TestAppContext) {
+        cx.update(|cx| {
+            theme::init(cx);
+            crate::init(cx);
+        });
+        let (view, cx) = cx.add_window_view(|window, cx| TestInput {
+            input: cx.new(|cx| InputState::new(window, cx)),
+            disabled: false,
+        });
+        let input = view.read_with(cx, |view, _| view.input.clone());
+        cx.update(|window, cx| {
+            input.update(cx, |state, cx| state.focus(window, cx));
+            window.draw(cx).clear(cx);
+            cx.write_to_clipboard(ClipboardItem::new_string("clipboard".into()));
+            cx.write_to_primary(ClipboardItem::new_string("primary".into()));
+        });
+        cx.simulate_keystrokes("shift-insert");
+        assert_eq!(input.read_with(cx, |state, _| state.value()), "clipboard");
+        cx.simulate_keystrokes("ctrl-a ctrl-v");
+        assert_eq!(input.read_with(cx, |state, _| state.value()), "clipboard");
+    }
+
+    #[test]
+    fn primary_paste_uses_visible_unicode_carets_and_clicked_row() {
+        let offset = primary_paste_offset("é\nx", point(px(8.), px(35.)), |offset| {
+            let (x, y) = match offset {
+                0 => return None,
+                2 => (10., 0.),
+                3 => (0., 20.),
+                4 => (10., 20.),
+                _ => panic!("offset must be a UTF-8 character boundary"),
+            };
+            Some(gpui::Bounds::new(
+                point(px(x), px(y)),
+                gpui::size(px(0.), px(20.)),
+            ))
+        });
+        assert_eq!(offset, Some(4));
+        assert_eq!(
+            primary_paste_offset("text", point(px(0.), px(0.)), |_| None),
+            None
+        );
+    }
+
+    #[gpui::test]
+    fn middle_click_preserves_disabled_and_readonly_fields(cx: &mut TestAppContext) {
+        cx.update(|cx| {
+            theme::init(cx);
+            crate::init(cx);
+        });
+        let (view, cx) = cx.add_window_view(|window, cx| TestInput {
+            input: cx.new(|cx| InputState::new(window, cx).default_value("unchanged")),
+            disabled: true,
+        });
+        let input = view.read_with(cx, |view, _| view.input.clone());
+        cx.update(|window, cx| {
+            window.draw(cx).clear(cx);
+            cx.write_to_primary(ClipboardItem::new_string("must not paste".into()));
+        });
+        cx.simulate_mouse_down(
+            point(px(20.), px(20.)),
+            MouseButton::Middle,
+            Default::default(),
+        );
+        cx.simulate_mouse_up(
+            point(px(20.), px(20.)),
+            MouseButton::Middle,
+            Default::default(),
+        );
+        assert_eq!(input.read_with(cx, |state, _| state.value()), "unchanged");
+        cx.update(|window, cx| {
+            view.update(cx, |view, cx| {
+                view.disabled = false;
+                cx.notify();
+            });
+            input.update(cx, |state, cx| state.set_readonly(true, cx));
+            window.draw(cx).clear(cx);
+        });
+        cx.simulate_mouse_down(
+            point(px(20.), px(20.)),
+            MouseButton::Middle,
+            Default::default(),
+        );
+        cx.simulate_mouse_up(
+            point(px(20.), px(20.)),
+            MouseButton::Middle,
+            Default::default(),
+        );
+        assert_eq!(input.read_with(cx, |state, _| state.value()), "unchanged");
+    }
+}

crates/ui/src/lib.rs

@@ -39,6 +39,12 @@ mod window_ext;
 /// You can initialize the UI module at your application's entry point.
 pub fn init(cx: &mut gpui::App) {
     gpui_base::init(cx);
+    #[cfg(not(target_os = "macos"))]
+    cx.bind_keys([gpui::KeyBinding::new(
+        "shift-insert",
+        gpui_base::input::Paste,
+        Some("Input"),
+    )]);
     theme::sync_base(cx);
     menu::init(cx);
 }