feat: add tab drop preview indicator for split pane drag-and-drop

packages/app/src/utils/inline-path.test.ts

@@ -92,6 +92,19 @@ describe("parseAssistantFileLink", () => {
     });
   });
 
+  it("parses absolute POSIX hrefs that use :line:column suffixes", () => {
+    expect(
+      parseAssistantFileLink("/Users/test/project/src/app.tsx:33:1", {
+        workspaceRoot: "/Users/test/project",
+      })
+    ).toEqual({
+      raw: "/Users/test/project/src/app.tsx:33:1",
+      path: "/Users/test/project/src/app.tsx",
+      lineStart: 33,
+      lineEnd: undefined,
+    });
+  });
+
   it("parses absolute Windows hrefs inside the active workspace", () => {
     expect(
       parseAssistantFileLink("C:/repo/src/app.tsx#L12-L20", {
@@ -105,6 +118,19 @@ describe("parseAssistantFileLink", () => {
     });
   });
 
+  it("parses absolute Windows hrefs that use :line:column suffixes", () => {
+    expect(
+      parseAssistantFileLink("C:/repo/src/app.tsx:12:4", {
+        workspaceRoot: "C:/repo",
+      })
+    ).toEqual({
+      raw: "C:/repo/src/app.tsx:12:4",
+      path: "C:/repo/src/app.tsx",
+      lineStart: 12,
+      lineEnd: undefined,
+    });
+  });
+
   it("allows file URLs even when they are outside the workspace root", () => {
     expect(
       parseAssistantFileLink("file:///tmp/outside.txt", {

packages/app/src/utils/inline-path.ts

@@ -51,6 +51,38 @@ function parseLineFragment(value: string): Pick<InlinePathTarget, "lineStart" |
   return { lineStart, lineEnd };
 }
 
+function parseTrailingLineSuffix(pathValue: string): {
+  path: string;
+  lineStart?: number;
+  lineEnd?: number;
+} | null {
+  const match = pathValue.match(/^(.*?):([0-9]+)(?::([0-9]+))?$/);
+  if (!match) {
+    return null;
+  }
+
+  const normalizedPath = normalizePathToken(match[1] ?? "");
+  if (!normalizedPath) {
+    return null;
+  }
+
+  const lineStart = parseInt(match[2] ?? "", 10);
+  if (!Number.isFinite(lineStart) || lineStart <= 0) {
+    return null;
+  }
+
+  const column = match[3] ? parseInt(match[3], 10) : undefined;
+  if (column !== undefined && (!Number.isFinite(column) || column <= 0)) {
+    return null;
+  }
+
+  return {
+    path: normalizedPath,
+    lineStart,
+    lineEnd: undefined,
+  };
+}
+
 /**
  * Strict VSCode-style markers only.
  *
@@ -166,12 +198,15 @@ export function parseAssistantFileLink(
 
   const windowsPathMatch = trimmed.match(/^([A-Za-z]:[\\/][^?#]*)(#[^?]+)?$/);
   if (windowsPathMatch) {
-    const normalizedPath = normalizePathToken(windowsPathMatch[1] ?? "");
+    const rawWindowsPath = windowsPathMatch[1] ?? "";
+    const windowsPathWithLine = parseTrailingLineSuffix(rawWindowsPath);
+    const normalizedPath =
+      windowsPathWithLine?.path ?? normalizePathToken(rawWindowsPath);
     if (!normalizedPath || !isAllowedAbsolutePath(normalizedPath, options.workspaceRoot)) {
       return null;
     }
 
-    const lines = parseLineFragment(windowsPathMatch[2] ?? "");
+    const lines = windowsPathWithLine ?? parseLineFragment(windowsPathMatch[2] ?? "");
     if (!lines) {
       return null;
     }
@@ -194,7 +229,9 @@ export function parseAssistantFileLink(
     return null;
   }
 
-  const normalizedPath = normalizePathToken(decodeURIComponent(parsedUrl.pathname));
+  const rawPosixPath = decodeURIComponent(parsedUrl.pathname);
+  const posixPathWithLine = parseTrailingLineSuffix(rawPosixPath);
+  const normalizedPath = posixPathWithLine?.path ?? normalizePathToken(rawPosixPath);
   if (!normalizedPath || !normalizedPath.startsWith("/")) {
     return null;
   }
@@ -203,7 +240,7 @@ export function parseAssistantFileLink(
     return null;
   }
 
-  const lines = parseLineFragment(parsedUrl.hash);
+  const lines = posixPathWithLine ?? parseLineFragment(parsedUrl.hash);
   if (!lines) {
     return null;
   }