feat: Resolve relative URIs in nitpick.styles.include

- Refactored fetchers to operate on furl parsed objects
- Relative URIs are resolved against the URI of the style file they are
  contained in.
- During normalization, `gh://` is mapped to `github://`, and
  `pypackge://` is mapped to `py://` to avoid loading styles more than
  once.

docs/nitpick_section.rst

@@ -72,6 +72,28 @@ Example of usage: :gitref:`Nitpick's default style <nitpick-style.toml>`.
     [nitpick.styles]
     include = ["styles/python37", "styles/poetry"]
 
-The styles will be merged following the sequence in the list.
+The styles will be merged following the sequence in the list. The ``.toml``
+extension for each referenced file can be onitted.
+
+Relative references are resolved relative to the URI of the style doument they
+are included in according to the `normal rules of RFC 3986 <https://www.rfc-editor.org/rfc/rfc3986.html#section-5.2>`_.
+
+E.g. for a style file located at
+``gh://$GITHUB_TOKEN@foo_dev/bar_project@branchname/styles/foobar.toml`` the following
+strings all reference the exact same canonical location to include:
+
+.. code-block:: toml
+
+    [nitpick.styles]
+    include = [
+      "foobar.toml",
+      "../styles/foobar.toml",
+      "/bar_project@branchname/styles/foobar.toml",
+      "//$GITHUB_TOKEN@foo_dev/bar_project@branchname/styles/foobar.toml",
+    ]
+
+For style files on the local filesystem, the canonical path
+(after symbolic links have been resolved) of the style file is used as the
+base.
 
 If a key/value pair appears in more than one sub-style, it will be overridden; the last declared key/pair will prevail.

src/nitpick/generic.py

@@ -6,15 +6,15 @@
 """
 from __future__ import annotations
 
-import re
+import sys
 from pathlib import Path
 from typing import Iterable
 
+from furl import Path as FurlPath
+
 from nitpick.constants import DOT, PROJECT_NAME
 from nitpick.typedefs import PathOrStr
 
-URL_RE = re.compile(r"[a-z]+://[\$\w]\w*")
-
 
 def version_to_tuple(version: str = None) -> tuple[int, ...]:
     """Transform a version number into a tuple of integers, for comparison.
@@ -43,27 +43,6 @@ def version_to_tuple(version: str = None) -> tuple[int, ...]:
     return tuple(int(part) for part in clean_version.split(DOT))
 
 
-def is_url(url: str) -> bool:
-    """Return True if a string is a URL.
-
-    >>> is_url("")
-    False
-    >>> is_url("  ")
-    False
-    >>> is_url("http://example.com")
-    True
-    >>> is_url("github://andreoliwa/nitpick/styles/black")
-    True
-    >>> is_url("github://$VARNAME@andreoliwa/nitpick/styles/black")
-    True
-    >>> is_url("github://LitErAl@andreoliwa/nitpick/styles/black")
-    True
-    >>> is_url("github://notfirst$@andreoliwa/nitpick/styles/black")
-    True
-    """
-    return bool(URL_RE.match(url))
-
-
 def relative_to_current_dir(path_or_str: PathOrStr | None) -> str:
     """Return a relative path to the current dir or an absolute path."""
     if not path_or_str:
@@ -108,3 +87,17 @@ def filter_names(iterable: Iterable, *partial_names: str) -> list[str]:
         if include:
             rv.append(name)
     return rv
+
+
+if sys.platform == "win32":
+
+    def furl_path_to_python_path(path: FurlPath) -> Path:
+        """Convert a file URL to a path."""
+        drive, *segments = path.segments
+        return Path(f"{drive}/", *segments)
+
+else:
+
+    def furl_path_to_python_path(path: FurlPath) -> Path:
+        """Convert a file URL to a path."""
+        return Path("/", *path.segments)

src/nitpick/project.py

@@ -3,11 +3,9 @@
 
 import itertools
 from dataclasses import dataclass
-from functools import lru_cache
 from pathlib import Path
 from typing import Iterable, Iterator
 
-import pluggy
 from autorepr import autorepr
 from loguru import logger
 from marshmallow_polyfield import PolyField
@@ -36,22 +34,22 @@
 from nitpick.exceptions import QuitComplainingError
 from nitpick.generic import version_to_tuple
 from nitpick.schemas import BaseNitpickSchema, flatten_marshmallow_errors, help_message
-from nitpick.typedefs import JsonDict, PathOrStr, mypy_property
+from nitpick.typedefs import JsonDict, PathOrStr
 from nitpick.violations import Fuss, ProjectViolations, Reporter, StyleViolations
 
 
 def glob_files(dir_: Path, file_patterns: Iterable[str]) -> set[Path]:
     """Search a directory looking for file patterns."""
     for pattern in file_patterns:
-        found_files = list(dir_.glob(pattern))
+        found_files = set(dir_.glob(pattern))
         if found_files:
-            return set(found_files)
+            return found_files
     return set()
 
 
 def confirm_project_root(dir_: PathOrStr | None = None) -> Path:
     """Confirm this is the root dir of the project (the one that has one of the ``ROOT_FILES``)."""
-    possible_root_dir = Path(dir_ or Path.cwd())
+    possible_root_dir = Path(dir_ or Path.cwd()).resolve()
     root_files = glob_files(possible_root_dir, ROOT_FILES)
     logger.debug(f"Root files found: {root_files}")
 
@@ -110,27 +108,35 @@ class Project:
 
     __repr__ = autorepr(["_chosen_root", "root"])
 
+    _plugin_manager: PluginManager
+    _confirmed_root: Path
+
     def __init__(self, root: PathOrStr = None) -> None:
         self._chosen_root = root
 
         self.style_dict: JsonDict = {}
         self.nitpick_section: JsonDict = {}
         self.nitpick_files_section: JsonDict = {}
 
-    @mypy_property
-    @lru_cache()
+    @property
     def root(self) -> Path:
         """Root dir of the project."""
-        return confirm_project_root(self._chosen_root)
+        try:
+            root = self._confirmed_root
+        except AttributeError:
+            root = self._confirmed_root = confirm_project_root(self._chosen_root)
+        return root
 
-    @mypy_property
-    @lru_cache()
+    @property
     def plugin_manager(self) -> PluginManager:
         """Load all defined plugins."""
-        plugin_manager = pluggy.PluginManager(PROJECT_NAME)
-        plugin_manager.add_hookspecs(plugins)
-        plugin_manager.load_setuptools_entrypoints(PROJECT_NAME)
-        return plugin_manager
+        try:
+            manager = self._plugin_manager
+        except AttributeError:
+            manager = self._plugin_manager = PluginManager(PROJECT_NAME)
+            manager.add_hookspecs(plugins)
+            manager.load_setuptools_entrypoints(PROJECT_NAME)
+        return manager
 
     def read_configuration(self) -> Configuration:
         """Search for a configuration file and validate it against a Marshmallow schema."""
@@ -175,7 +181,8 @@ def merge_styles(self, offline: bool) -> Iterator[Fuss]:
         from nitpick.style import StyleManager
 
         style = StyleManager(self, offline, config.cache)
-        style_errors = list(style.find_initial_styles(peekable(always_iterable(config.styles))))
+        base = config.file.expanduser().resolve().as_uri() if config.file else None
+        style_errors = list(style.find_initial_styles(peekable(always_iterable(config.styles)), base))
         if style_errors:
             raise QuitComplainingError(style_errors)
 
@@ -209,7 +216,7 @@ def create_configuration(self, config: Configuration) -> None:
         tool_nitpick = table()
         tool_nitpick.add(comment("Generated by the 'nitpick init' command"))
         tool_nitpick.add(comment(f"More info at {READ_THE_DOCS_URL}configuration.html"))
-        tool_nitpick.add("style", [StyleManager.get_default_style_url()])
+        tool_nitpick.add("style", [str(StyleManager.get_default_style_url())])
         doc.add(SingleKey(TOOL_NITPICK_KEY, KeyType.Bare), tool_nitpick)
 
         # config.file will always have a value at this point, but mypy can't see it.