fix: Handle combined mouse event and paste sequences in stdin buffer

packages/core/src/lib/parse.mouse.test.ts

@@ -0,0 +1,142 @@
+import { describe, expect, it, beforeEach } from "bun:test"
+import { MouseParser } from "./parse.mouse"
+
+describe("MouseParser", () => {
+  let parser: MouseParser
+
+  beforeEach(() => {
+    parser = new MouseParser()
+  })
+
+  describe("parseMouseEvent (backward compatibility)", () => {
+    it("should parse SGR mouse down event", () => {
+      const data = Buffer.from("\x1b[<0;10;20M")
+      const event = parser.parseMouseEvent(data)
+
+      expect(event).not.toBeNull()
+      expect(event!.type).toBe("down")
+      expect(event!.button).toBe(0)
+      expect(event!.x).toBe(9)
+      expect(event!.y).toBe(19)
+    })
+
+    it("should parse SGR mouse up event", () => {
+      const data = Buffer.from("\x1b[<0;10;20m")
+      const event = parser.parseMouseEvent(data)
+
+      expect(event).not.toBeNull()
+      expect(event!.type).toBe("up")
+    })
+
+    it("should return null for non-mouse data", () => {
+      const data = Buffer.from("hello")
+      const event = parser.parseMouseEvent(data)
+
+      expect(event).toBeNull()
+    })
+  })
+
+  describe("parseMouseEventWithConsumed", () => {
+    it("should return consumed byte count for SGR mouse event", () => {
+      const data = Buffer.from("\x1b[<0;10;20M")
+      const result = parser.parseMouseEventWithConsumed(data)
+
+      expect(result).not.toBeNull()
+      expect(result!.event.type).toBe("down")
+      expect(result!.consumed).toBe(11) // \x1b[<0;10;20M is 11 bytes
+    })
+
+    it("should return consumed byte count for basic mouse event", () => {
+      // Basic mouse mode: \x1b[M followed by 3 bytes (button+32, x+33, y+33)
+      // Button 0 + 32 = 32 (space), x=1 + 33 = 34 ("), y=1 + 33 = 34 (")
+      const data = Buffer.from('\x1b[M ""')
+      const result = parser.parseMouseEventWithConsumed(data)
+
+      expect(result).not.toBeNull()
+      expect(result!.consumed).toBe(6)
+    })
+
+    it("should only match mouse event at start of buffer", () => {
+      // Data with non-mouse prefix followed by mouse event
+      const data = Buffer.from("prefix\x1b[<0;10;20M")
+      const result = parser.parseMouseEventWithConsumed(data)
+
+      // Should NOT match because mouse event is not at the start
+      expect(result).toBeNull()
+    })
+
+    it("should handle combined mouse event and paste sequence (Alacritty-style)", () => {
+      // This simulates Alacritty's drag-drop behavior:
+      // Mouse motion event + bracketed paste in a single chunk
+      // Button 35 = 32 (motion) + 3 (no button) = move event
+      const mouseSeq = "\x1b[<35;37;18M"
+      const pasteSeq = "\x1b[200~/home/user/file.jpg \x1b[201~"
+      const combined = Buffer.from(mouseSeq + pasteSeq)
+
+      const result = parser.parseMouseEventWithConsumed(combined)
+
+      expect(result).not.toBeNull()
+      expect(result!.event.type).toBe("move")
+      expect(result!.consumed).toBe(Buffer.byteLength(mouseSeq))
+
+      // Verify remaining data contains the paste sequence
+      const remaining = combined.slice(result!.consumed)
+      expect(remaining.toString()).toBe(pasteSeq)
+    })
+
+    it("should correctly calculate consumed bytes for varying coordinate lengths", () => {
+      // Single digit coordinates: \x1b[<0;1;1M = 9 bytes
+      const data1 = Buffer.from("\x1b[<0;1;1M")
+      const result1 = parser.parseMouseEventWithConsumed(data1)
+      expect(result1!.consumed).toBe(9)
+
+      // Double digit coordinates: \x1b[<0;10;20M = 11 bytes
+      const data2 = Buffer.from("\x1b[<0;10;20M")
+      const result2 = parser.parseMouseEventWithConsumed(data2)
+      expect(result2!.consumed).toBe(11)
+
+      // Triple digit coordinates: \x1b[<0;100;200M = 13 bytes
+      const data3 = Buffer.from("\x1b[<0;100;200M")
+      const result3 = parser.parseMouseEventWithConsumed(data3)
+      expect(result3!.consumed).toBe(13)
+    })
+
+    it("should parse scroll events correctly", () => {
+      // Scroll up: button code 64 (scroll bit) + 0 (up direction) = 64
+      const data = Buffer.from("\x1b[<64;10;20M")
+      const result = parser.parseMouseEventWithConsumed(data)
+
+      expect(result).not.toBeNull()
+      expect(result!.event.type).toBe("scroll")
+      expect(result!.event.scroll?.direction).toBe("up")
+    })
+
+    it("should parse motion events correctly", () => {
+      // Motion: button code 32 (motion bit) + 3 (no button) = 35
+      const data = Buffer.from("\x1b[<35;10;20M")
+      const result = parser.parseMouseEventWithConsumed(data)
+
+      expect(result).not.toBeNull()
+      expect(result!.event.type).toBe("move")
+    })
+
+    it("should parse modifier keys correctly", () => {
+      // Shift (4) + button 0 = 4
+      const shiftClick = Buffer.from("\x1b[<4;10;20M")
+      const shiftResult = parser.parseMouseEventWithConsumed(shiftClick)
+      expect(shiftResult!.event.modifiers.shift).toBe(true)
+      expect(shiftResult!.event.modifiers.alt).toBe(false)
+      expect(shiftResult!.event.modifiers.ctrl).toBe(false)
+
+      // Alt (8) + button 0 = 8
+      const altClick = Buffer.from("\x1b[<8;10;20M")
+      const altResult = parser.parseMouseEventWithConsumed(altClick)
+      expect(altResult!.event.modifiers.alt).toBe(true)
+
+      // Ctrl (16) + button 0 = 16
+      const ctrlClick = Buffer.from("\x1b[<16;10;20M")
+      const ctrlResult = parser.parseMouseEventWithConsumed(ctrlClick)
+      expect(ctrlResult!.event.modifiers.ctrl).toBe(true)
+    })
+  })
+})

packages/core/src/lib/parse.mouse.ts

@@ -14,6 +14,11 @@ export type RawMouseEvent = {
   scroll?: ScrollInfo
 }
 
+export type MouseParseResult = {
+  event: RawMouseEvent
+  consumed: number
+}
+
 export class MouseParser {
   private mouseButtonsPressed = new Set<number>()
 
@@ -28,12 +33,17 @@ export class MouseParser {
     this.mouseButtonsPressed.clear()
   }
 
-  public parseMouseEvent(data: Buffer): RawMouseEvent | null {
+  /**
+   * Parse a mouse event from the buffer and return the consumed byte count.
+   * This allows the caller to process any remaining data in the buffer.
+   */
+  public parseMouseEventWithConsumed(data: Buffer): MouseParseResult | null {
     const str = data.toString()
     // Parse SGR mouse mode: \x1b[<b;x;yM or \x1b[<b;x;ym
-    const sgrMatch = str.match(/\x1b\[<(\d+);(\d+);(\d+)([Mm])/)
+    // Anchor to start of string to ensure we only match at the beginning
+    const sgrMatch = str.match(/^(\x1b\[<(\d+);(\d+);(\d+)([Mm]))/)
     if (sgrMatch) {
-      const [, buttonCode, x, y, pressRelease] = sgrMatch
+      const [, fullMatch, buttonCode, x, y, pressRelease] = sgrMatch
       const rawButtonCode = parseInt(buttonCode)
 
       const button = rawButtonCode & 3
@@ -77,12 +87,15 @@ export class MouseParser {
       }
 
       return {
-        type,
-        button: button === 3 ? 0 : button,
-        x: parseInt(x) - 1,
-        y: parseInt(y) - 1,
-        modifiers,
-        scroll: scrollInfo,
+        event: {
+          type,
+          button: button === 3 ? 0 : button,
+          x: parseInt(x) - 1,
+          y: parseInt(y) - 1,
+          modifiers,
+          scroll: scrollInfo,
+        },
+        consumed: Buffer.byteLength(fullMatch),
       }
     }
 
@@ -120,15 +133,27 @@ export class MouseParser {
       }
 
       return {
-        type,
-        button: actualButton,
-        x,
-        y,
-        modifiers,
-        scroll: scrollInfo,
+        event: {
+          type,
+          button: actualButton,
+          x,
+          y,
+          modifiers,
+          scroll: scrollInfo,
+        },
+        consumed: 6,
       }
     }
 
     return null
   }
+
+  /**
+   * Parse a mouse event from the buffer.
+   * @deprecated Use parseMouseEventWithConsumed() when you need to handle remaining buffer data.
+   */
+  public parseMouseEvent(data: Buffer): RawMouseEvent | null {
+    const result = this.parseMouseEventWithConsumed(data)
+    return result ? result.event : null
+  }
 }

packages/core/src/renderer.ts

@@ -1039,9 +1039,18 @@ export class CliRenderer extends EventEmitter implements RenderContext {
   }
 
   private handleMouseData(data: Buffer): boolean {
-    const mouseEvent = this.mouseParser.parseMouseEvent(data)
+    const result = this.mouseParser.parseMouseEventWithConsumed(data)
+
+    if (result) {
+      const { event: mouseEvent, consumed } = result
+
+      // Process any remaining data in the buffer (e.g., paste data that follows a mouse event)
+      // This handles terminals like Alacritty that combine mouse events with other sequences
+      if (consumed < data.length) {
+        const remaining = data.slice(consumed)
+        this._stdinBuffer.process(remaining)
+      }
 
-    if (mouseEvent) {
       if (this._splitHeight > 0) {
         if (mouseEvent.y < this.renderOffset) {
           return false

packages/core/src/testing/integration.test.ts

@@ -24,16 +24,10 @@ function parseAllEvents(emittedData: Buffer, parser: MouseParser) {
   const parsedEvents: NonNullable<ReturnType<MouseParser["parseMouseEvent"]>>[] = []
   let offset = 0
   while (offset < emittedData.length) {
-    const event = parser.parseMouseEvent(emittedData.subarray(offset))
-    if (event) {
-      parsedEvents.push(event)
-      const str = emittedData.subarray(offset).toString()
-      const match = str.match(/\x1b\[<[^Mm]*[Mm]/)
-      if (match) {
-        offset += match[0].length
-      } else {
-        break
-      }
+    const result = parser.parseMouseEventWithConsumed(emittedData.subarray(offset))
+    if (result) {
+      parsedEvents.push(result.event)
+      offset += result.consumed
     } else {
       break
     }