Better cmake_binary Resolution

Author: Behemyth

cppython/plugins/cmake/resolution.py

@@ -1,13 +1,62 @@
 """Builder to help resolve cmake state"""
 
+import logging
 import os
+import shutil
 from pathlib import Path
 from typing import Any
 
 from cppython.core.schema import CorePluginData
 from cppython.plugins.cmake.schema import CMakeConfiguration, CMakeData
 
 
+def _resolve_cmake_binary(configured_path: Path | None) -> Path | None:
+    """Resolve the cmake binary path with validation.
+
+    Resolution order:
+    1. CMAKE_BINARY environment variable (highest priority)
+    2. Configured path from cmake_binary setting
+    3. cmake from PATH (fallback)
+
+    If a path is specified (via env or config) but doesn't exist,
+    a warning is logged and we fall back to PATH lookup.
+
+    Args:
+        configured_path: The cmake_binary path from configuration, if any
+
+    Returns:
+        Resolved cmake path, or None if not found anywhere
+    """
+    logger = logging.getLogger('cppython.cmake')
+
+    # Environment variable takes precedence
+    if env_binary := os.environ.get('CMAKE_BINARY'):
+        env_path = Path(env_binary)
+        if env_path.exists():
+            return env_path
+        logger.warning(
+            'CMAKE_BINARY environment variable points to non-existent path: %s. '
+            'Falling back to PATH lookup.',
+            env_binary,
+        )
+
+    # Try configured path
+    if configured_path:
+        if configured_path.exists():
+            return configured_path
+        logger.warning(
+            'Configured cmake_binary path does not exist: %s. '
+            'Falling back to PATH lookup.',
+            configured_path,
+        )
+
+    # Fall back to PATH lookup
+    if cmake_in_path := shutil.which('cmake'):
+        return Path(cmake_in_path)
+
+    return None
+
+
 def resolve_cmake_data(data: dict[str, Any], core_data: CorePluginData) -> CMakeData:
     """Resolves the input data table from defaults to requirements
 
@@ -27,11 +76,7 @@ def resolve_cmake_data(data: dict[str, Any], core_data: CorePluginData) -> CMake
         modified_preset_file = root_directory / modified_preset_file
 
     # Resolve cmake binary: environment variable takes precedence over configuration
-    cmake_binary: Path | None = None
-    if env_binary := os.environ.get('CMAKE_BINARY'):
-        cmake_binary = Path(env_binary)
-    elif parsed_data.cmake_binary:
-        cmake_binary = parsed_data.cmake_binary
+    cmake_binary = _resolve_cmake_binary(parsed_data.cmake_binary)
 
     return CMakeData(
         preset_file=modified_preset_file, configuration_name=parsed_data.configuration_name, cmake_binary=cmake_binary

cppython/plugins/conan/plugin.py

@@ -6,7 +6,6 @@
 """
 
 import os
-import shutil
 from logging import Logger, getLogger
 from pathlib import Path
 from typing import Any
@@ -242,23 +241,6 @@ def sync_data(self, consumer: SyncConsumer) -> SyncData:
 
         raise NotSupportedError(f'Unsupported sync types: {consumer.sync_types()}')
 
-    @staticmethod
-    def _resolve_cmake_binary(cmake_path: Path | str | None) -> str | None:
-        """Resolve the cmake binary path.
-
-        If an explicit path is provided, use it. Otherwise, try to find cmake
-        in the current Python environment (venv) to ensure we use the same
-        cmake version for all operations including dependency builds.
-
-        Args:
-            cmake_path: Explicit cmake path, or None to auto-detect
-
-        Returns:
-            Resolved cmake path as string, or None if not found
-        """
-        resolved = cmake_path or shutil.which('cmake')
-        return str(Path(resolved).resolve()) if resolved else None
-
     def _sync_with_cmake(self, consumer: SyncConsumer) -> CMakeSyncData:
         """Synchronize with CMake generator and create sync data.
 
@@ -269,8 +251,9 @@ def _sync_with_cmake(self, consumer: SyncConsumer) -> CMakeSyncData:
             CMakeSyncData configured for Conan integration
         """
         # Extract cmake_binary from CMakeGenerator if available
-        if isinstance(consumer, CMakeGenerator) and not os.environ.get('CMAKE_BINARY'):
-            self._cmake_binary = self._resolve_cmake_binary(consumer.data.cmake_binary)
+        # The cmake_binary is already validated and resolved during CMake data resolution
+        if isinstance(consumer, CMakeGenerator) and consumer.data.cmake_binary:
+            self._cmake_binary = str(consumer.data.cmake_binary.resolve())
 
         return self._create_cmake_sync_data()