From a5bd20c65bbb6ca15ec72b8eede1c9e8e58d65e1 Mon Sep 17 00:00:00 2001
From: danshapiro <danshapiro@example.com>
Date: Thu, 13 Aug 2026 23:54:07 -0700
Subject: [PATCH] fix(paths): recognize Windows absolute paths
 (drive-letter/UNC) in parse_uri

C:/..., C:\..., and \\server\share\... URIs previously fell through to the
package-name heuristic, so no source handler claimed them and resolution
failed with 'No handler for URI' on native Windows. This surfaced when
settings.yaml referenced local behaviors/bundles via Windows paths, and when
relative module entries inside cached bundles were resolved to absolute OS
path strings (strict mode then aborted session startup).

Fixes https://github.com/microsoft/amplifier/issues/374
---
 amplifier_foundation/paths/resolution.py |  9 ++++++++
 tests/test_paths.py                      | 28 ++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/amplifier_foundation/paths/resolution.py b/amplifier_foundation/paths/resolution.py
index 92e88ccf..f7216e53 100644
--- a/amplifier_foundation/paths/resolution.py
+++ b/amplifier_foundation/paths/resolution.py
@@ -105,6 +105,8 @@ def parse_uri(uri: str) -> ParsedURI:
     - zip+file:///local/archive.zip#subdirectory=path/inside
     - file:///path/to/file
     - /absolute/path
+    - C:\absolute\path or C:/absolute/path (Windows)
+    - \\server\share\path (Windows UNC)
     - ./relative/path
     - package-name
     - package/subpath
@@ -136,6 +138,13 @@ def parse_uri(uri: str) -> ParsedURI:
     if uri.startswith("./") or uri.startswith("../"):
         return ParsedURI(scheme="file", host="", path=uri, ref="", subpath="")
 
+    # Handle Windows absolute paths (drive-letter or UNC)
+    is_drive_path = (
+        len(uri) >= 3 and uri[0].isalpha() and uri[1] == ":" and uri[2] in "/\\"
+    )
+    if is_drive_path or uri.startswith("\\\\"):
+        return ParsedURI(scheme="file", host="", path=uri, ref="", subpath="")
+
     # Handle http/https URLs
     if uri.startswith("http://") or uri.startswith("https://"):
         parsed = urlparse(uri)
diff --git a/tests/test_paths.py b/tests/test_paths.py
index ae9a059b..eeaa70d8 100644
--- a/tests/test_paths.py
+++ b/tests/test_paths.py
@@ -135,6 +135,34 @@ def test_relative_path(self) -> None:
         assert result.scheme == "file"
         assert result.path == "./bundles/my-bundle"
 
+    def test_windows_drive_letter_path(self) -> None:
+        """Parses Windows drive-letter paths as file URIs."""
+        result = parse_uri("C:/Users/test/bundle")
+        assert result.scheme == "file"
+        assert result.path == "C:/Users/test/bundle"
+        assert result.is_file
+
+    def test_windows_drive_letter_backslash_path(self) -> None:
+        """Parses Windows backslash drive-letter paths as file URIs."""
+        result = parse_uri(r"C:\Users\test\bundle")
+        assert result.scheme == "file"
+        assert result.path == r"C:\Users\test\bundle"
+        assert result.is_file
+
+    def test_windows_unc_path(self) -> None:
+        """Parses Windows UNC paths as file URIs."""
+        result = parse_uri(r"\\server\share\bundle")
+        assert result.scheme == "file"
+        assert result.path == r"\\server\share\bundle"
+        assert result.is_file
+
+    def test_windows_file_uri_with_drive_letter(self) -> None:
+        """Parses file:// URIs containing a drive letter."""
+        result = parse_uri("file://C:/Users/test/bundle")
+        assert result.scheme == "file"
+        assert result.path == "C:/Users/test/bundle"
+        assert result.is_file
+
 
 class TestNormalizePath:
     """Tests for normalize_path function."""