fix: overwrite character under cursor with space in replace mode

Author: leohenon

packages/opencode/src/cli/cmd/tui/component/vim/vim-handler.ts

@@ -65,7 +65,12 @@ export function createVimHandler(input: {
   }
 
   function isPrintable(event: VimEvent) {
-    return !!event.name && event.name.length === 1
+    return !!event.name && (event.name.length === 1 || event.name === "space")
+  }
+
+  function value(event: VimEvent) {
+    if (event.name === "space") return " "
+    return event.name ?? ""
   }
 
   function isShifted(event: VimEvent, key: string) {
@@ -560,7 +565,7 @@ export function createVimHandler(input: {
         }
 
         if (isPrintable(event) && !hasModifier(event)) {
-          replaceUnderCursor(input.textarea(), event.name)
+          replaceUnderCursor(input.textarea(), value(event))
           input.state.setTyped(true)
           event.preventDefault()
           return true

packages/opencode/test/cli/tui/vim-motions.test.ts

@@ -721,6 +721,17 @@ describe("vim motion handler", () => {
     expect(ctx.state.mode()).toBe("replace")
   })
 
+  test("replace mode overwrites with space key", () => {
+    const ctx = createHandler("abcd", { mode: "replace" })
+    ctx.textarea.cursorOffset = 1
+
+    const key = createEvent("space")
+    expect(ctx.handler.handleKey(key.event)).toBe(true)
+    expect(key.prevented()).toBe(true)
+    expect(ctx.textarea.plainText).toBe("a cd")
+    expect(ctx.textarea.cursorOffset).toBe(2)
+  })
+
   test("replace mode inserts at line end without removing newline", () => {
     const ctx = createHandler("ab\ncd", { mode: "replace" })
     ctx.textarea.cursorOffset = 2