Introduce an egregious hack to work around older CI toolchains

Blame Owen for the evil genius of this hack, me for trying to put it in

Author: DougGregor

Tests/CommandsTests/PackageCommandTests.swift

@@ -1953,13 +1953,13 @@ final class PackageCommandTests: CommandsTestCase {
 
         try fixture(name: "Miscellaneous/Plugins/CommandPluginTestStub") { fixturePath in
             func runPlugin(flags: [String], diagnostics: [String], completion: (String, String) -> Void) throws {
-                let (stdout, stderr) = try SwiftPM.Package.execute(flags + ["print-diagnostics"] + diagnostics, packagePath: fixturePath)
+                let (stdout, stderr) = try SwiftPM.Package.execute(flags + ["print-diagnostics"] + diagnostics, packagePath: fixturePath, env: ["SWIFT_DRIVER_SWIFTSCAN_LIB" : "/this/is/a/bad/path"])
                 completion(stdout, stderr)
             }
 
             // Diagnostics.error causes SwiftPM to return a non-zero exit code, but we still need to check stdout and stderr
             func runPluginWithError(flags: [String], diagnostics: [String], completion: (String, String) -> Void) throws {
-                XCTAssertThrowsError(try SwiftPM.Package.execute(flags + ["print-diagnostics"] + diagnostics, packagePath: fixturePath)) { error in
+                XCTAssertThrowsError(try SwiftPM.Package.execute(flags + ["print-diagnostics"] + diagnostics, packagePath: fixturePath, env: ["SWIFT_DRIVER_SWIFTSCAN_LIB" : "/this/is/a/bad/path"])) { error in
                     guard case SwiftPMError.executionFailure(_, let stdout, let stderr) = error else {
                         return XCTFail("invalid error \(error)")
                     }
@@ -2151,28 +2151,28 @@ final class PackageCommandTests: CommandsTestCase {
 
         // Check than nothing is echoed when echoLogs is false
         try fixture(name: "Miscellaneous/Plugins/CommandPluginTestStub") { fixturePath in
-            let (stdout, stderr) = try SwiftPM.Package.execute(["print-diagnostics", "build"], packagePath: fixturePath)
+            let (stdout, stderr) = try SwiftPM.Package.execute(["print-diagnostics", "build"], packagePath: fixturePath, env: ["SWIFT_DRIVER_SWIFTSCAN_LIB" : "/this/is/a/bad/path"])
             XCTAssertMatch(stdout, isEmpty)
             XCTAssertMatch(stderr, isEmpty)
         }
 
         // Check that logs are returned to the plugin when echoLogs is false
         try fixture(name: "Miscellaneous/Plugins/CommandPluginTestStub") { fixturePath in
-            let (stdout, stderr) = try SwiftPM.Package.execute(["print-diagnostics", "build", "printlogs"], packagePath: fixturePath)
+            let (stdout, stderr) = try SwiftPM.Package.execute(["print-diagnostics", "build", "printlogs"], packagePath: fixturePath, env: ["SWIFT_DRIVER_SWIFTSCAN_LIB" : "/this/is/a/bad/path"])
             XCTAssertMatch(stdout, containsLogtext)
             XCTAssertMatch(stderr, isEmpty)
         }
 
         // Check that logs echoed to the console (on stderr) when echoLogs is true
         try fixture(name: "Miscellaneous/Plugins/CommandPluginTestStub") { fixturePath in
-            let (stdout, stderr) = try SwiftPM.Package.execute(["print-diagnostics", "build", "echologs"], packagePath: fixturePath)
+            let (stdout, stderr) = try SwiftPM.Package.execute(["print-diagnostics", "build", "echologs"], packagePath: fixturePath, env: ["SWIFT_DRIVER_SWIFTSCAN_LIB" : "/this/is/a/bad/path"])
             XCTAssertMatch(stdout, isEmpty)
             XCTAssertMatch(stderr, containsLogecho)
         }
 
         // Check that logs are returned to the plugin and echoed to the console (on stderr) when echoLogs is true
         try fixture(name: "Miscellaneous/Plugins/CommandPluginTestStub") { fixturePath in
-            let (stdout, stderr) = try SwiftPM.Package.execute(["print-diagnostics", "build", "printlogs", "echologs"], packagePath: fixturePath)
+            let (stdout, stderr) = try SwiftPM.Package.execute(["print-diagnostics", "build", "printlogs", "echologs"], packagePath: fixturePath, env: ["SWIFT_DRIVER_SWIFTSCAN_LIB" : "/this/is/a/bad/path"])
             XCTAssertMatch(stdout, containsLogtext)
             XCTAssertMatch(stderr, containsLogecho)
         }
@@ -2465,14 +2465,14 @@ final class PackageCommandTests: CommandsTestCase {
 
             // Check arguments
             do {
-                let (stdout, stderr) = try SwiftPM.Package.execute(["plugin", "MyPlugin", "--foo", "--help", "--version", "--verbose"], packagePath: packageDir)
+                let (stdout, stderr) = try SwiftPM.Package.execute(["plugin", "MyPlugin", "--foo", "--help", "--version", "--verbose"], packagePath: packageDir, env: ["SWIFT_DRIVER_SWIFTSCAN_LIB" : "/this/is/a/bad/path"])
                 XCTAssertMatch(stdout, .contains("success"))
                 XCTAssertEqual(stderr, "")
             }
 
             // Check default command arguments
             do {
-                let (stdout, stderr) = try SwiftPM.Package.execute(["MyPlugin", "--foo", "--help", "--version", "--verbose"], packagePath: packageDir)
+                let (stdout, stderr) = try SwiftPM.Package.execute(["MyPlugin", "--foo", "--help", "--version", "--verbose"], packagePath: packageDir, env: ["SWIFT_DRIVER_SWIFTSCAN_LIB" : "/this/is/a/bad/path"])
                 XCTAssertMatch(stdout, .contains("success"))
                 XCTAssertEqual(stderr, "")
             }

Tests/FunctionalTests/MiscellaneousTests.swift

@@ -665,7 +665,7 @@ class MiscellaneousTestCase: XCTestCase {
 
     func testRootPackageWithConditionals() throws {
         try fixture(name: "Miscellaneous/RootPackageWithConditionals") { path in
-            let (_, stderr) = try SwiftPM.Build.execute(packagePath: path)
+            let (_, stderr) = try SwiftPM.Build.execute(packagePath: path, env: ["SWIFT_DRIVER_SWIFTSCAN_LIB" : "/this/is/a/bad/path"])
             let errors = stderr.components(separatedBy: .newlines).filter { !$0.contains("[logging] misuse") && !$0.isEmpty }
             XCTAssertEqual(errors, [], "unexpected errors: \(errors)")
         }

Tests/FunctionalTests/PluginTests.swift

@@ -227,12 +227,12 @@ final class PluginTests: XCTestCase {
             let pathOfGeneratedFile = packageDir.appending(components: [".build", "plugins", "outputs", "mypackage", "SomeTarget", "Plugin", "best.txt"])
 
             try createPackageUnderTest(packageDir: packageDir, toolsVersion: .v5_9)
-            let (_, stderr) = try executeSwiftBuild(packageDir)
+            let (_, stderr) = try executeSwiftBuild(packageDir, env: ["SWIFT_DRIVER_SWIFTSCAN_LIB" : "/this/is/a/bad/path"])
             XCTAssertTrue(stderr.contains("warning: Build tool command 'empty' (applied to target 'SomeTarget') does not declare any output files"), "expected warning not emitted")
             XCTAssertFalse(localFileSystem.exists(pathOfGeneratedFile), "plugin generated file unexpectedly exists at \(pathOfGeneratedFile.pathString)")
 
             try createPackageUnderTest(packageDir: packageDir, toolsVersion: .v6_0)
-            let (_, stderr2) = try executeSwiftBuild(packageDir)
+            let (_, stderr2) = try executeSwiftBuild(packageDir, env: ["SWIFT_DRIVER_SWIFTSCAN_LIB" : "/this/is/a/bad/path"])
             XCTAssertEqual("", stderr2)
             XCTAssertTrue(localFileSystem.exists(pathOfGeneratedFile), "plugin did not run, generated file does not exist at \(pathOfGeneratedFile.pathString)")
         }

Tests/FunctionalTests/ResourcesTests.swift

@@ -157,7 +157,7 @@ class ResourcesTests: XCTestCase {
             try localFileSystem.createDirectory(resource.parentDirectory, recursive: true)
             try localFileSystem.writeFileContents(resource, string: "best")
 
-            let (_, stderr) = try executeSwiftBuild(packageDir, env: ["DYLD_PRINT_SEARCHING": "1"])
+            let (_, stderr) = try executeSwiftBuild(packageDir, env: ["SWIFT_DRIVER_SWIFTSCAN_LIB" : "/this/is/a/bad/path"])
             // Filter some unrelated output that could show up on stderr.
             let filteredStderr = stderr.components(separatedBy: "\n").filter { !$0.contains("[logging]") }.joined(separator: "\n")
             XCTAssertEqual(filteredStderr, "", "unexpectedly received error output: \(stderr)")