Fail closed on conditional SafeDI scanning

Sources/SafeDICore/Models/SafeDIToolManifest.swift

@@ -22,6 +22,16 @@
 /// All input file paths are relative to the working directory where the tool is invoked.
 /// Output file paths may be absolute or relative to the working directory.
 public struct SafeDIToolManifest: Codable, Sendable {
+	private enum CodingKeys: String, CodingKey {
+		case dependencyTreeGeneration
+		case mockGeneration
+		case configurationFilePaths
+		case mockConfigurationOutputFilePath
+		case additionalMocksToGenerate
+		case additionalInputFiles
+		case activeCompilationConditions
+	}
+
 	/// A mapping from an input Swift file to an output file.
 	public struct InputOutputMap: Codable, Sendable {
 		/// The path to the input Swift file containing one or more root `@Instantiable` declarations.
@@ -65,19 +75,37 @@ public struct SafeDIToolManifest: Codable, Sendable {
 	/// Only populated by the `scan` subcommand; ignored by `generate`.
 	public var additionalInputFiles: [String]
 
+	/// Active conditional compilation flags used while scanning SafeDI declarations.
+	public var activeCompilationConditions: [String]
+
 	public init(
 		dependencyTreeGeneration: [InputOutputMap],
 		mockGeneration: [InputOutputMap] = [],
 		configurationFilePaths: [String] = [],
 		mockConfigurationOutputFilePath: String? = nil,
 		additionalMocksToGenerate: [String] = [],
 		additionalInputFiles: [String] = [],
+		activeCompilationConditions: [String] = [],
 	) {
 		self.dependencyTreeGeneration = dependencyTreeGeneration
 		self.mockGeneration = mockGeneration
 		self.configurationFilePaths = configurationFilePaths
 		self.mockConfigurationOutputFilePath = mockConfigurationOutputFilePath
 		self.additionalMocksToGenerate = additionalMocksToGenerate
 		self.additionalInputFiles = additionalInputFiles
+		self.activeCompilationConditions = activeCompilationConditions
+	}
+
+	public init(from decoder: Decoder) throws {
+		let container = try decoder.container(keyedBy: CodingKeys.self)
+		self.init(
+			dependencyTreeGeneration: try container.decode([InputOutputMap].self, forKey: .dependencyTreeGeneration),
+			mockGeneration: try container.decodeIfPresent([InputOutputMap].self, forKey: .mockGeneration) ?? [],
+			configurationFilePaths: try container.decodeIfPresent([String].self, forKey: .configurationFilePaths) ?? [],
+			mockConfigurationOutputFilePath: try container.decodeIfPresent(String.self, forKey: .mockConfigurationOutputFilePath),
+			additionalMocksToGenerate: try container.decodeIfPresent([String].self, forKey: .additionalMocksToGenerate) ?? [],
+			additionalInputFiles: try container.decodeIfPresent([String].self, forKey: .additionalInputFiles) ?? [],
+			activeCompilationConditions: try container.decodeIfPresent([String].self, forKey: .activeCompilationConditions) ?? [],
+		)
 	}
 }

Sources/SafeDICore/Models/UnevaluableConditionalCompilationConditionError.swift

@@ -0,0 +1,40 @@
+// Distributed under the MIT License
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+public struct UnevaluableConditionalCompilationConditionError: Error, CustomStringConvertible, Equatable, Sendable {
+	public let condition: String
+	public let suggestedActiveCondition: String?
+
+	public init(
+		condition: String,
+		suggestedActiveCondition: String? = nil,
+	) {
+		self.condition = condition
+		self.suggestedActiveCondition = suggestedActiveCondition
+	}
+
+	public var description: String {
+		if let suggestedActiveCondition {
+			"Unable to evaluate conditional compilation condition `\(condition)` while scanning SafeDI declarations. Pass the active condition to SafeDITool with `--active-compilation-conditions \(suggestedActiveCondition)`, or remove the SafeDI declaration from the conditional branch."
+		} else {
+			"Unable to evaluate conditional compilation condition `\(condition)` while scanning SafeDI declarations. SafeDITool can only evaluate boolean literals, `!`, `&&`, `||`, parentheses, and active custom compilation conditions while scanning SafeDI declarations."
+		}
+	}
+}