Fix readFileRange Kotlin Int overflow in IntelliJ plugin

core/tools/implementations/readFileRange.integration.vitest.ts

@@ -1,6 +1,6 @@
 import { expect, test, vi } from "vitest";
 import { ToolExtras } from "../..";
-import { readFileRangeImpl } from "./readFileRange";
+import { MAX_CHAR_POSITION, readFileRangeImpl } from "./readFileRange";
 
 // Mock the dependencies
 vi.mock("../../util/ideUtils", () => ({
@@ -76,15 +76,15 @@ test("readFileRangeImpl handles out-of-bounds ranges gracefully", async () => {
     "file:///test.txt",
     {
       start: { line: 99, character: 0 }, // 100 - 1
-      end: { line: 104, character: Number.MAX_SAFE_INTEGER }, // 105 - 1
+      end: { line: 104, character: MAX_CHAR_POSITION }, // 105 - 1
     },
   );
 
   expect(mockIdePartialRange.readRangeInFile).toHaveBeenCalledWith(
     "file:///test.txt",
     {
       start: { line: 4, character: 0 }, // 5 - 1
-      end: { line: 99, character: Number.MAX_SAFE_INTEGER }, // 100 - 1
+      end: { line: 99, character: MAX_CHAR_POSITION }, // 100 - 1
     },
   );
 });
@@ -199,6 +199,6 @@ test("readFileRangeImpl handles normal ranges correctly", async () => {
   // Verify correct 0-based conversion
   expect(mockIde.readRangeInFile).toHaveBeenCalledWith("file:///test.txt", {
     start: { line: 1, character: 0 }, // 2 - 1
-    end: { line: 3, character: Number.MAX_SAFE_INTEGER }, // 4 - 1
+    end: { line: 3, character: MAX_CHAR_POSITION }, // 4 - 1
   });
 });

core/tools/implementations/readFileRange.ts

@@ -7,6 +7,10 @@ import { getNumberArg, getStringArg } from "../parseArgs";
 import { throwIfFileExceedsHalfOfContext } from "./readFileLimit";
 import { ContinueError, ContinueErrorReason } from "../../util/errors";
 
+// Use Int.MAX_VALUE from Java/Kotlin (2^31 - 1) instead of JavaScript's Number.MAX_SAFE_INTEGER
+// to ensure compatibility with IntelliJ's Kotlin Position type which uses Int for character field
+export const MAX_CHAR_POSITION = 2147483647;
+
 export const readFileRangeImpl: ToolImpl = async (args, extras) => {
   const filepath = getStringArg(args, "filepath");
   const startLine = getNumberArg(args, "startLine");
@@ -52,7 +56,7 @@ export const readFileRangeImpl: ToolImpl = async (args, extras) => {
     },
     end: {
       line: endLine - 1, // Convert from 1-based to 0-based
-      character: Number.MAX_SAFE_INTEGER, // Read to end of line
+      character: MAX_CHAR_POSITION, // Read to end of line
     },
   });