Fix error message on Windows (#210)

.pre-commit-config.yaml

@@ -33,7 +33,7 @@ repos:
       - id: end-of-file-fixer
         name: end-of-file-fixer
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.4.2
+    rev: v0.4.6
     hooks:
       - id: ruff
         args:
@@ -99,7 +99,7 @@ repos:
           - platformdirs
           - wcmatch
   - repo: https://github.com/tcort/markdown-link-check
-    rev: v3.12.1
+    rev: v3.12.2
     hooks:
       - id: markdown-link-check
         name: markdown-link-check

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "mkdocs-include-markdown-plugin"
-version = "6.0.6"
+version = "6.0.7"
 description = "Mkdocs Markdown includer plugin."
 readme = "README.md"
 license = "Apache-2.0"

src/mkdocs_include_markdown_plugin/event.py

@@ -58,6 +58,22 @@ def lineno_from_content_start(content: str, start: int) -> int:
     return content[:start].count('\n') + 1
 
 
+def safe_os_path_relpath(path: str, start: str) -> str:
+    """Return the relative path of a file from a start directory.
+
+    Safe version of `os.path.relpath` that catches `ValueError` exceptions
+    on Windows and returns the original path in case of error.
+    On Windows, `ValueError` is raised when `path` and `start` are on
+    different drives.
+    """
+    if os.name != 'nt':  # pragma: nt no cover
+        return os.path.relpath(path, start)
+    try:  # pragma: nt cover
+        return os.path.relpath(path, start)
+    except ValueError:  # pragma: no cover
+        return path
+
+
 def file_lineno_message(
         page_src_path: str | None,
         docs_dir: str,
@@ -67,7 +83,7 @@ def file_lineno_message(
     if page_src_path is None:  # pragma: no cover
         return f'generated page content (line {lineno})'
     return (
-        f'{os.path.relpath(page_src_path, docs_dir)}'
+        f'{safe_os_path_relpath(page_src_path, docs_dir)}'
         f':{lineno}'
     )
 
@@ -287,7 +303,7 @@ def found_include_tag(  # noqa: PLR0912, PLR0915
             if expected_but_any_found[i]:
                 delimiter_value = locals()[delimiter_name]
                 readable_files_to_include = ', '.join([
-                    os.path.relpath(fpath, docs_dir)
+                    safe_os_path_relpath(fpath, docs_dir)
                     for fpath in file_paths_to_include
                 ])
                 plural_suffix = 's' if len(file_paths_to_include) > 1 else ''
@@ -593,7 +609,7 @@ def found_include_markdown_tag(  # noqa: PLR0912, PLR0915
             if expected_but_any_found[i]:
                 delimiter_value = locals()[delimiter_name]
                 readable_files_to_include = ', '.join([
-                    os.path.relpath(fpath, docs_dir)
+                    safe_os_path_relpath(fpath, docs_dir)
                     for fpath in file_paths_to_include
                 ])
                 plural_suffix = 's' if len(file_paths_to_include) > 1 else ''