refactor: pull out overrides to separate file

Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com>

docs/api/scikit_build_core.settings.rst

@@ -57,6 +57,14 @@ scikit\_build\_core.settings.skbuild\_model module
    :undoc-members:
    :show-inheritance:
 
+scikit\_build\_core.settings.skbuild\_overrides module
+------------------------------------------------------
+
+.. automodule:: scikit_build_core.settings.skbuild_overrides
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
 scikit\_build\_core.settings.skbuild\_read\_settings module
 -----------------------------------------------------------
 

src/scikit_build_core/settings/skbuild_overrides.py

@@ -0,0 +1,298 @@
+from __future__ import annotations
+
+import os
+import platform
+import re
+import sys
+from pathlib import Path
+from typing import TYPE_CHECKING, Any
+
+from packaging.specifiers import SpecifierSet
+
+from .._logging import logger
+
+__all__ = ["process_overides", "regex_match"]
+
+
+def __dir__() -> list[str]:
+    return __all__
+
+
+if TYPE_CHECKING:
+    from collections.abc import Mapping
+
+    from .._compat.typing import Literal
+
+
+def strtobool(value: str) -> bool:
+    """
+    Converts a environment variable string into a boolean value.
+    """
+    value = value.lower()
+    if value.isdigit():
+        return bool(int(value))
+    return value in {"y", "yes", "on", "true", "t"}
+
+
+def version_match(value: str, match: str, name: str) -> str:
+    """
+    Returns a non-empty string if a version matches a specifier.
+    """
+    matcher = SpecifierSet(match)
+    did_match = matcher.contains(value)
+    return f"{match!r} matched {name} {value}" if did_match else ""
+
+
+def regex_match(value: str, match: str) -> str:
+    """
+    Returns a non-empty string if a value matches a regex.
+    """
+    did_match = re.compile(match).search(value) is not None
+    return f"{match!r} matched {value!r}" if did_match else ""
+
+
+def override_match(
+    *,
+    current_env: Mapping[str, str] | None,
+    current_state: Literal[
+        "sdist", "wheel", "editable", "metadata_wheel", "metadata_editable"
+    ],
+    has_dist_info: bool,
+    retry: bool,
+    python_version: str | None = None,
+    implementation_name: str | None = None,
+    implementation_version: str | None = None,
+    platform_system: str | None = None,
+    platform_machine: str | None = None,
+    platform_node: str | None = None,
+    env: dict[str, str] | None = None,
+    state: str | None = None,
+    from_sdist: bool | None = None,
+    failed: bool | None = None,
+) -> tuple[dict[str, str], set[str]]:
+    """
+    Check if the current environment matches the overrides. Returns a dict
+    of passed matches, with reasons for values, and a set of non-matches.
+    """
+
+    passed_dict = {}
+    failed_set: set[str] = set()
+
+    if current_env is None:
+        current_env = os.environ
+
+    if python_version is not None:
+        current_python_version = ".".join(str(x) for x in sys.version_info[:2])
+        match_msg = version_match(current_python_version, python_version, "Python")
+        if match_msg:
+            passed_dict["python-version"] = match_msg
+        else:
+            failed_set.add("python-version")
+
+    if implementation_name is not None:
+        current_impementation_name = sys.implementation.name
+        match_msg = regex_match(current_impementation_name, implementation_name)
+        if match_msg:
+            passed_dict["implementation-name"] = match_msg
+        else:
+            failed_set.add("implementation-name")
+
+    if implementation_version is not None:
+        info = sys.implementation.version
+        version = f"{info.major}.{info.minor}.{info.micro}"
+        kind = info.releaselevel
+        if kind != "final":
+            version += f"{kind[0]}{info.serial}"
+        match_msg = version_match(
+            version, implementation_version, "Python implementation"
+        )
+        if match_msg:
+            passed_dict["implementation-version"] = match_msg
+        else:
+            failed_set.add("implementation-version")
+
+    if platform_system is not None:
+        current_platform_system = sys.platform
+        match_msg = regex_match(current_platform_system, platform_system)
+        if match_msg:
+            passed_dict["platform-system"] = match_msg
+        else:
+            failed_set.add("platform-system")
+
+    if platform_machine is not None:
+        current_platform_machine = platform.machine()
+        match_msg = regex_match(current_platform_machine, platform_machine)
+        if match_msg:
+            passed_dict["platform-machine"] = match_msg
+        else:
+            failed_set.add("platform-machine")
+
+    if platform_node is not None:
+        current_platform_node = platform.node()
+        match_msg = regex_match(current_platform_node, platform_node)
+        if match_msg:
+            passed_dict["platform-node"] = match_msg
+        else:
+            failed_set.add("platform-node")
+
+    if state is not None:
+        match_msg = regex_match(current_state, state)
+        if match_msg:
+            passed_dict["state"] = match_msg
+        else:
+            failed_set.add("state")
+
+    if failed is not None:
+        if failed and retry:
+            passed_dict["failed"] = "Previous run failed"
+        elif not failed and not retry:
+            passed_dict["failed"] = "Running on a fresh run"
+        else:
+            failed_set.add("failed")
+
+    if from_sdist is not None:
+        if has_dist_info:
+            if from_sdist:
+                passed_dict["from-sdist"] = "from sdist due to PKG-INFO"
+            else:
+                failed_set.add("from-sdist")
+        elif not from_sdist:
+            passed_dict["from-sdist"] = "not from sdist, no PKG-INFO"
+        else:
+            failed_set.add("from-sdist")
+
+    if env:
+        for key, value in env.items():
+            if key not in current_env:
+                failed_set.add(f"env.{key}")
+            elif isinstance(value, bool):
+                if strtobool(current_env[key]) == value:
+                    passed_dict[f"env.{key}"] = f"env {key} is {value}"
+                else:
+                    failed_set.add(f"env.{key}")
+            else:
+                current_value = current_env[key]
+                match_msg = regex_match(current_value, value)
+
+                if match_msg:
+                    passed_dict[f"env.{key}"] = f"env {key}: {match_msg}"
+                else:
+                    failed_set.add(f"env.{key}")
+
+    if not passed_dict and not failed_set:
+        msg = "At least one override must be provided"
+        raise ValueError(msg)
+
+    return passed_dict, failed_set
+
+
+def inherit_join(
+    value: list[str] | dict[str, str] | str | int | bool,
+    previous: list[str] | dict[str, str] | str | int | bool | None,
+    mode: str,
+) -> list[str] | dict[str, str] | str | int | bool:
+    if mode not in {"none", "append", "prepend"}:
+        msg = "Only 'none', 'append', and 'prepend' supported for inherit"
+        raise TypeError(msg)
+    if mode == "none" or previous is None:
+        return value
+    if isinstance(previous, list) and isinstance(value, list):
+        return [*previous, *value] if mode == "append" else [*value, *previous]
+    if isinstance(previous, dict) and isinstance(value, dict):
+        return {**previous, **value} if mode == "append" else {**value, **previous}
+    msg = "Append/prepend modes can only be used on lists or dicts"
+    raise TypeError(msg)
+
+
+def process_overides(
+    tool_skb: dict[str, Any],
+    *,
+    state: Literal["sdist", "wheel", "editable", "metadata_wheel", "metadata_editable"],
+    retry: bool,
+    env: Mapping[str, str] | None = None,
+) -> set[str]:
+    """
+    Process overrides into the main dictionary if they match. Modifies the input
+    dictionary. Must be run from the package directory.
+    """
+    has_dist_info = Path("PKG-INFO").is_file()
+
+    global_matched: set[str] = set()
+    for override in tool_skb.pop("overrides", []):
+        passed_any: dict[str, str] | None = None
+        passed_all: dict[str, str] | None = None
+        failed: set[str] = set()
+        if_override = override.pop("if", None)
+        if not if_override:
+            msg = "At least one 'if' override must be provided"
+            raise KeyError(msg)
+        if not isinstance(if_override, dict):
+            msg = "'if' override must be a table"
+            raise TypeError(msg)
+        if "any" in if_override:
+            any_override = if_override.pop("any")
+            select = {k.replace("-", "_"): v for k, v in any_override.items()}
+            passed_any, _ = override_match(
+                current_env=env,
+                current_state=state,
+                has_dist_info=has_dist_info,
+                retry=retry,
+                **select,
+            )
+
+        inherit_override = override.pop("inherit", {})
+        if not isinstance(inherit_override, dict):
+            msg = "'inherit' override must be a table"
+            raise TypeError(msg)
+
+        select = {k.replace("-", "_"): v for k, v in if_override.items()}
+        if select:
+            passed_all, failed = override_match(
+                current_env=env,
+                current_state=state,
+                has_dist_info=has_dist_info,
+                retry=retry,
+                **select,
+            )
+
+        # If no overrides are passed, do nothing
+        if passed_any is None and passed_all is None:
+            continue
+
+        # If normal overrides are passed and one or more fails, do nothing
+        if passed_all is not None and failed:
+            continue
+
+        # If any is passed, at least one always needs to pass.
+        if passed_any is not None and not passed_any:
+            continue
+
+        local_matched = set(passed_any or []) | set(passed_all or [])
+        global_matched |= local_matched
+        if local_matched:
+            all_str = " and ".join(
+                [
+                    *(passed_all or {}).values(),
+                    *([" or ".join(passed_any.values())] if passed_any else []),
+                ]
+            )
+            logger.info("Overrides {}", all_str)
+
+            for key, value in override.items():
+                inherit1 = inherit_override.get(key, {})
+                if isinstance(value, dict):
+                    for key2, value2 in value.items():
+                        inherit2 = inherit1.get(key2, "none")
+                        inner = tool_skb.get(key, {})
+                        inner[key2] = inherit_join(
+                            value2, inner.get(key2, None), inherit2
+                        )
+                        tool_skb[key] = inner
+                else:
+                    inherit_override_tmp = inherit_override or "none"
+                    if isinstance(inherit_override_tmp, dict):
+                        assert not inherit_override_tmp
+                    tool_skb[key] = inherit_join(
+                        value, tool_skb.get(key), inherit_override_tmp
+                    )
+    return global_matched