fix(npm): canonicalize filename before returning (#18948)

This commit changes how paths for npm packages are handled,
by canonicalizing them when resolving. This is done so that instead
of returning
"node_modules/<package_name>@<version>/node_modules/<dep>/index.js"
(which is a symlink) we "node_modules/<dep>@<dep_version>/index.js.

Fixes https://github.com/denoland/deno/issues/18924
Fixes https://github.com/bluwy/create-vite-extra/issues/31

---------

Co-authored-by: David Sherret <dsherret@gmail.com>

1 files changed, 91 insertions, 0 deletions

diff --git a/core/path.rs b/core/path.rs
new file mode 100644
index 000000000..fd8b1a9b6
--- /dev/null
+++ b/core/path.rs
@@ -0,0 +1,91 @@
+// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
+
+use std::path::PathBuf;
+
+#[cfg(not(windows))]
+#[inline]
+pub fn strip_unc_prefix(path: PathBuf) -> PathBuf {
+  path
+}
+
+/// Strips the unc prefix (ex. \\?\) from Windows paths.
+#[cfg(windows)]
+pub fn strip_unc_prefix(path: PathBuf) -> PathBuf {
+  use std::path::Component;
+  use std::path::Prefix;
+
+  let mut components = path.components();
+  match components.next() {
+    Some(Component::Prefix(prefix)) => {
+      match prefix.kind() {
+        // \\?\device
+        Prefix::Verbatim(device) => {
+          let mut path = PathBuf::new();
+          path.push(format!(r"\\{}\", device.to_string_lossy()));
+          path.extend(components.filter(|c| !matches!(c, Component::RootDir)));
+          path
+        }
+        // \\?\c:\path
+        Prefix::VerbatimDisk(_) => {
+          let mut path = PathBuf::new();
+          path.push(prefix.as_os_str().to_string_lossy().replace(r"\\?\", ""));
+          path.extend(components);
+          path
+        }
+        // \\?\UNC\hostname\share_name\path
+        Prefix::VerbatimUNC(hostname, share_name) => {
+          let mut path = PathBuf::new();
+          path.push(format!(
+            r"\\{}\{}\",
+            hostname.to_string_lossy(),
+            share_name.to_string_lossy()
+          ));
+          path.extend(components.filter(|c| !matches!(c, Component::RootDir)));
+          path
+        }
+        _ => path,
+      }
+    }
+    _ => path,
+  }
+}
+
+#[cfg(test)]
+mod test {
+  #[cfg(windows)]
+  #[test]
+  fn test_strip_unc_prefix() {
+    use std::path::PathBuf;
+
+    run_test(r"C:\", r"C:\");
+    run_test(r"C:\test\file.txt", r"C:\test\file.txt");
+
+    run_test(r"\\?\C:\", r"C:\");
+    run_test(r"\\?\C:\test\file.txt", r"C:\test\file.txt");
+
+    run_test(r"\\.\C:\", r"\\.\C:\");
+    run_test(r"\\.\C:\Test\file.txt", r"\\.\C:\Test\file.txt");
+
+    run_test(r"\\?\UNC\localhost\", r"\\localhost");
+    run_test(r"\\?\UNC\localhost\c$\", r"\\localhost\c$");
+    run_test(
+      r"\\?\UNC\localhost\c$\Windows\file.txt",
+      r"\\localhost\c$\Windows\file.txt",
+    );
+    run_test(r"\\?\UNC\wsl$\deno.json", r"\\wsl$\deno.json");
+
+    run_test(r"\\?\server1", r"\\server1");
+    run_test(r"\\?\server1\e$\", r"\\server1\e$\");
+    run_test(
+      r"\\?\server1\e$\test\file.txt",
+      r"\\server1\e$\test\file.txt",
+    );
+
+    fn run_test(input: &str, expected: &str) {
+      assert_eq!(
+        super::strip_unc_prefix(PathBuf::from(input)),
+        PathBuf::from(expected)
+      );
+    }
+  }
+}