Support type casting on configuration option values defined by enviro…

…nment variables (#5860)

CHANGELOG.md

@@ -26,6 +26,12 @@
   [Martin Redington](https://github.com/mildm8nnered)
   [#5801](https://github.com/realm/SwiftLint/issues/5801)
 
+* Support type casting on configuration option values defined by environment variables.
+  Without a cast, these values would always be treated as strings leading to a potentially
+  invalid configuration.  
+  [SimplyDanny](https://github.com/SimplyDanny)
+  [#5774](https://github.com/realm/SwiftLint/issues/5774)
+
 * The `redundant_type_annotation` rule gains a new option,
   `ignore_properties`, that skips enforcement on members in a
   type declaration (like a `struct`). This helps the rule coexist with

Source/SwiftLintCore/Models/YamlParser.swift

@@ -31,40 +31,28 @@ private extension Constructor {
 
     static func customScalarMap(env: [String: String]) -> ScalarMap {
         var map = defaultScalarMap
-        map[.str] = String.constructExpandingEnvVars(env: env)
-        map[.bool] = Bool.constructUsingOnlyTrueAndFalse
-
+        map[.str] = { $0.string.expandingEnvVars(env: env) }
+        map[.bool] = {
+            switch $0.string.expandingEnvVars(env: env).lowercased() {
+            case "true": true
+            case "false": false
+            default: nil
+            }
+        }
+        map[.int] = { Int($0.string.expandingEnvVars(env: env)) }
+        map[.float] = { Double($0.string.expandingEnvVars(env: env)) }
         return map
     }
 }
 
 private extension String {
-    static func constructExpandingEnvVars(env: [String: String]) -> (_ scalar: Node.Scalar) -> String? {
-        { (scalar: Node.Scalar) -> String? in
-            scalar.string.expandingEnvVars(env: env)
-        }
-    }
-
     func expandingEnvVars(env: [String: String]) -> String {
-        var result = self
-        for (key, value) in env {
-            result = result.replacingOccurrences(of: "${\(key)}", with: value)
+        guard contains("${") else {
+            // No environment variables used.
+            return self
         }
-
-        return result
-    }
-}
-
-private extension Bool {
-    // swiftlint:disable:next discouraged_optional_boolean
-    static func constructUsingOnlyTrueAndFalse(from scalar: Node.Scalar) -> Bool? {
-        switch scalar.string.lowercased() {
-        case "true":
-            return true
-        case "false":
-            return false
-        default:
-            return nil
+        return env.reduce(into: self) { result, envVar in
+            result = result.replacingOccurrences(of: "${\(envVar.key)}", with: envVar.value)
         }
     }
 }

Tests/SwiftLintFrameworkTests/YamlParserTests.swift

@@ -53,4 +53,48 @@ final class YamlParserTests: SwiftLintTestCase {
             _ = try YamlParser.parse("|\na", env: [:])
         }
     }
+
+    func testTreatAllEnvVarsAsStringsWithoutCasting() throws {
+        let env = [
+            "INT": "1",
+            "FLOAT": "1.0",
+            "BOOL": "true",
+            "STRING": "string",
+        ]
+        let string = """
+            int: ${INT}
+            float: ${FLOAT}
+            bool: ${BOOL}
+            string: ${STRING}
+            """
+
+        let result = try YamlParser.parse(string, env: env)
+
+        XCTAssertEqual(result["int"] as? String, "1")
+        XCTAssertEqual(result["float"] as? String, "1.0")
+        XCTAssertEqual(result["bool"] as? String, "true")
+        XCTAssertEqual(result["string"] as? String, "string")
+    }
+
+    func testRespectCastsOnEnvVars() throws {
+        let env = [
+            "INT": "1",
+            "FLOAT": "1.0",
+            "BOOL": "true",
+            "STRING": "string",
+        ]
+        let string = """
+            int: !!int ${INT}
+            float: !!float ${FLOAT}
+            bool: !!bool ${BOOL}
+            string: !!str ${STRING}
+            """
+
+        let result = try YamlParser.parse(string, env: env)
+
+        XCTAssertEqual(result["int"] as? Int, 1)
+        XCTAssertEqual(result["float"] as? Double, 1.0)
+        XCTAssertEqual(result["bool"] as? Bool, true)
+        XCTAssertEqual(result["string"] as? String, "string")
+    }
 }