fix: trim trailing whitespace from terminal clipboard copies

Fixes #2778. xterm.js getSelection() returns lines padded to the full
terminal column width, resulting in hundreds of trailing spaces when
pasting into external apps.

Adds a term:trimtrailingwhitespace setting (default true) that strips
trailing whitespace from each line before writing to the clipboard.
Applies to all three copy paths: copy-on-select, Ctrl+Shift+C, and
right-click Copy.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Drew-Goddyn

frontend/app/view/term/term-model.ts

@@ -40,7 +40,7 @@ import { boundNumber, fireAndForget, stringToBase64 } from "@/util/util";
 import * as jotai from "jotai";
 import * as React from "react";
 import { getBlockingCommand } from "./shellblocking";
-import { computeTheme, DefaultTermTheme } from "./termutil";
+import { computeTheme, DefaultTermTheme, trimTerminalSelection } from "./termutil";
 import { TermWrap, WebGLSupported } from "./termwrap";
 
 export class TermViewModel implements ViewModel {
@@ -750,10 +750,13 @@ export class TermViewModel implements ViewModel {
         } else if (keyutil.checkKeyPressed(waveEvent, "Ctrl:Shift:c")) {
             event.preventDefault();
             event.stopPropagation();
-            const sel = this.termRef.current?.terminal.getSelection();
+            let sel = this.termRef.current?.terminal.getSelection();
             if (!sel) {
                 return false;
             }
+            if (globalStore.get(getSettingsKeyAtom("term:trimtrailingwhitespace")) !== false) {
+                sel = trimTerminalSelection(sel);
+            }
             navigator.clipboard.writeText(sel);
             return false;
         } else if (keyutil.checkKeyPressed(waveEvent, "Cmd:k")) {
@@ -829,7 +832,11 @@ export class TermViewModel implements ViewModel {
                 label: "Copy",
                 click: () => {
                     if (selection) {
-                        navigator.clipboard.writeText(selection);
+                        const text =
+                            globalStore.get(getSettingsKeyAtom("term:trimtrailingwhitespace")) !== false
+                                ? trimTerminalSelection(selection)
+                                : selection;
+                        navigator.clipboard.writeText(text);
                     }
                 },
             });

frontend/app/view/term/termutil.ts

@@ -10,6 +10,13 @@ import { colord } from "colord";
 
 export type GenClipboardItem = { text?: string; image?: Blob };
 
+export function trimTerminalSelection(text: string): string {
+    return text
+        .split("\n")
+        .map((line) => line.trimEnd())
+        .join("\n");
+}
+
 export function normalizeCursorStyle(cursorStyle: string): TermTypes.Terminal["options"]["cursorStyle"] {
     if (cursorStyle === "underline" || cursorStyle === "bar") {
         return cursorStyle;

frontend/app/view/term/termwrap.ts

@@ -42,6 +42,7 @@ import {
     extractAllClipboardData,
     normalizeCursorStyle,
     quoteForPosixShell,
+    trimTerminalSelection,
 } from "./termutil";
 
 const dlog = debug("wave:termwrap");
@@ -380,6 +381,7 @@ export class TermWrap {
 
     async initTerminal() {
         const copyOnSelectAtom = getSettingsKeyAtom("term:copyonselect");
+        const trimTrailingWhitespaceAtom = getSettingsKeyAtom("term:trimtrailingwhitespace");
         this.toDispose.push(this.terminal.onData(this.handleTermData.bind(this)));
         this.toDispose.push(
             this.terminal.onSelectionChange(
@@ -393,8 +395,11 @@ export class TermWrap {
                     if (active != null && active.closest(".search-container") != null) {
                         return;
                     }
-                    const selectedText = this.terminal.getSelection();
+                    let selectedText = this.terminal.getSelection();
                     if (selectedText.length > 0) {
+                        if (globalStore.get(trimTrailingWhitespaceAtom) !== false) {
+                            selectedText = trimTerminalSelection(selectedText);
+                        }
                         navigator.clipboard.writeText(selectedText);
                     }
                 })

frontend/types/gotypes.d.ts

@@ -1423,6 +1423,7 @@ declare global {
         "term:osc52"?: string;
         "term:durable"?: boolean;
         "term:showsplitbuttons"?: boolean;
+        "term:trimtrailingwhitespace"?: boolean;
         "editor:minimapenabled"?: boolean;
         "editor:stickyscrollenabled"?: boolean;
         "editor:wordwrap"?: boolean;

pkg/wconfig/defaultconfig/settings.json

@@ -36,6 +36,7 @@
     "term:cursor": "block",
     "term:cursorblink": false,
     "term:copyonselect": true,
+    "term:trimtrailingwhitespace": true,
     "term:durable": false,
     "waveai:showcloudmodes": true,
     "waveai:defaultmode": "waveai@balanced",

pkg/wconfig/metaconsts.go

@@ -60,6 +60,7 @@ const (
 	ConfigKey_TermOsc52                      = "term:osc52"
 	ConfigKey_TermDurable                    = "term:durable"
 	ConfigKey_TermShowSplitButtons           = "term:showsplitbuttons"
+	ConfigKey_TermTrimTrailingWhitespace     = "term:trimtrailingwhitespace"
 
 	ConfigKey_EditorMinimapEnabled           = "editor:minimapenabled"
 	ConfigKey_EditorStickyScrollEnabled      = "editor:stickyscrollenabled"

pkg/wconfig/settingsconfig.go

@@ -109,8 +109,9 @@ type SettingsType struct {
 	TermBellSound           *bool    `json:"term:bellsound,omitempty"`
 	TermBellIndicator       *bool    `json:"term:bellindicator,omitempty"`
 	TermOsc52               string   `json:"term:osc52,omitempty" jsonschema:"enum=focus,enum=always"`
-	TermDurable             *bool    `json:"term:durable,omitempty"`
-	TermShowSplitButtons    bool     `json:"term:showsplitbuttons,omitempty"`
+	TermDurable                    *bool    `json:"term:durable,omitempty"`
+	TermShowSplitButtons           bool     `json:"term:showsplitbuttons,omitempty"`
+	TermTrimTrailingWhitespace     *bool    `json:"term:trimtrailingwhitespace,omitempty"`
 
 	EditorMinimapEnabled      bool    `json:"editor:minimapenabled,omitempty"`
 	EditorStickyScrollEnabled bool    `json:"editor:stickyscrollenabled,omitempty"`

schema/settings.json

@@ -171,6 +171,9 @@
         "term:showsplitbuttons": {
           "type": "boolean"
         },
+        "term:trimtrailingwhitespace": {
+          "type": "boolean"
+        },
         "editor:minimapenabled": {
           "type": "boolean"
         },