fix realpath behavior in windows (#3425)

2 files changed, 15 insertions, 3 deletions

diff --git a/cli/js/realpath_test.ts b/cli/js/realpath_test.ts
index 1dc976578..1faac94cc 100644
--- a/cli/js/realpath_test.ts
+++ b/cli/js/realpath_test.ts
@@ -4,7 +4,11 @@ import { testPerm, assert, assertEquals } from "./test_util.ts";
 testPerm({ read: true }, function realpathSyncSuccess(): void {
   const incompletePath = "cli/tests/fixture.json";
   const realPath = Deno.realpathSync(incompletePath);
-  assert(realPath.startsWith("/"));
+  if (Deno.build.os !== "win") {
+    assert(realPath.startsWith("/"));
+  } else {
+    assert(/^[A-Z]/.test(realPath));
+  }
   assert(realPath.endsWith(incompletePath));
 });
 
@@ -47,7 +51,11 @@ testPerm({ read: true }, function realpathSyncNotFound(): void {
 testPerm({ read: true }, async function realpathSuccess(): Promise<void> {
   const incompletePath = "cli/tests/fixture.json";
   const realPath = await Deno.realpath(incompletePath);
-  assert(realPath.startsWith("/"));
+  if (Deno.build.os !== "win") {
+    assert(realPath.startsWith("/"));
+  } else {
+    assert(/^[A-Z]/.test(realPath));
+  }
   assert(realPath.endsWith(incompletePath));
 });
 
diff --git a/cli/ops/fs.rs b/cli/ops/fs.rs
index 54ac1971b..c847931ab 100644
--- a/cli/ops/fs.rs
+++ b/cli/ops/fs.rs
@@ -300,7 +300,11 @@ fn op_realpath(
     // corresponds to the realpath on Unix and
     // CreateFile and GetFinalPathNameByHandle on Windows
     let realpath = fs::canonicalize(&path)?;
-    let realpath_str = realpath.to_str().unwrap().to_owned().replace("\\", "/");
+    let mut realpath_str =
+      realpath.to_str().unwrap().to_owned().replace("\\", "/");
+    if cfg!(windows) {
+      realpath_str = realpath_str.trim_start_matches("//?/").to_string();
+    }
     Ok(json!(realpath_str))
   })
 }