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

@@ -38,7 +38,7 @@ import { boundNumber, 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 } from "./termwrap";
 
 export class TermViewModel implements ViewModel {
@@ -631,10 +631,13 @@ 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")) {
@@ -692,7 +695,11 @@ 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

@@ -9,6 +9,13 @@ 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");
+}
+
 function applyTransparencyToColor(hexColor: string, transparency: number): string {
     const alpha = 1 - transparency; // transparency is already 0-1
     return colord(hexColor).alpha(alpha).toHex();

frontend/app/view/term/termwrap.ts

@@ -30,7 +30,7 @@ import debug from "debug";
 import * as jotai from "jotai";
 import { debounce } from "throttle-debounce";
 import { FitAddon } from "./fitaddon";
-import { createTempFileFromBlob, extractAllClipboardData } from "./termutil";
+import { createTempFileFromBlob, extractAllClipboardData, trimTerminalSelection } from "./termutil";
 
 const dlog = debug("wave:termwrap");
 
@@ -555,6 +555,7 @@ 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.onKey(this.onKeyHandler.bind(this)));
         this.toDispose.push(
@@ -563,8 +564,11 @@ export class TermWrap {
                     if (!globalStore.get(copyOnSelectAtom)) {
                         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

@@ -1250,6 +1250,7 @@ declare global {
         "term:macoptionismeta"?: boolean;
         "term:bellsound"?: boolean;
         "term:bellindicator"?: boolean;
+        "term:trimtrailingwhitespace"?: boolean;
         "editor:minimapenabled"?: boolean;
         "editor:stickyscrollenabled"?: boolean;
         "editor:wordwrap"?: boolean;

pkg/wconfig/defaultconfig/settings.json

@@ -27,6 +27,7 @@
     "term:bellsound": false,
     "term:bellindicator": true,
     "term:copyonselect": true,
+    "term:trimtrailingwhitespace": true,
     "waveai:showcloudmodes": true,
     "waveai:defaultmode": "waveai@balanced"
 }

pkg/wconfig/metaconsts.go

@@ -50,6 +50,7 @@ const (
 	ConfigKey_TermMacOptionIsMeta            = "term:macoptionismeta"
 	ConfigKey_TermBellSound                  = "term:bellsound"
 	ConfigKey_TermBellIndicator              = "term:bellindicator"
+	ConfigKey_TermTrimTrailingWhitespace     = "term:trimtrailingwhitespace"
 
 	ConfigKey_EditorMinimapEnabled           = "editor:minimapenabled"
 	ConfigKey_EditorStickyScrollEnabled      = "editor:stickyscrollenabled"

pkg/wconfig/settingsconfig.go

@@ -95,8 +95,9 @@ type SettingsType struct {
 	TermAllowBracketedPaste *bool    `json:"term:allowbracketedpaste,omitempty"`
 	TermShiftEnterNewline   *bool    `json:"term:shiftenternewline,omitempty"`
 	TermMacOptionIsMeta     *bool    `json:"term:macoptionismeta,omitempty"`
-	TermBellSound           *bool    `json:"term:bellsound,omitempty"`
-	TermBellIndicator       *bool    `json:"term:bellindicator,omitempty"`
+	TermBellSound                  *bool    `json:"term:bellsound,omitempty"`
+	TermBellIndicator              *bool    `json:"term:bellindicator,omitempty"`
+	TermTrimTrailingWhitespace     *bool    `json:"term:trimtrailingwhitespace,omitempty"`
 
 	EditorMinimapEnabled      bool    `json:"editor:minimapenabled,omitempty"`
 	EditorStickyScrollEnabled bool    `json:"editor:stickyscrollenabled,omitempty"`

schema/settings.json

@@ -128,6 +128,9 @@
         "term:bellindicator": {
           "type": "boolean"
         },
+        "term:trimtrailingwhitespace": {
+          "type": "boolean"
+        },
         "editor:minimapenabled": {
           "type": "boolean"
         },