Build plugin executables with debug symbols (#5665)

This seems like the better default until we might add a dedicated debugging feature for plugins.

Author: neonichu

Sources/Workspace/DefaultPluginScriptRunner.swift

@@ -164,6 +164,8 @@ public struct DefaultPluginScriptRunner: PluginScriptRunner, Cancellable {
         // Add any extra flags required as indicated by the ManifestLoader.
         commandLine += self.toolchain.swiftCompilerFlags
 
+        commandLine.append("-g")
+
         // Add the Swift language version implied by the package tools version.
         commandLine += ["-swift-version", toolsVersion.swiftLanguageVersion.rawValue]
 

Tests/SPMBuildCoreTests/PluginInvocationTests.swift

@@ -373,13 +373,6 @@ class PluginInvocationTests: XCTestCase {
                 XCTAssert(result.compilerOutput.contains("warning: variable 'unused' was never used"), "\(result.compilerOutput)")
                 XCTAssert(result.diagnosticsFile.suffix == ".dia", "\(result.diagnosticsFile.pathString)")
 
-                // Check the serialized diagnostics. We should no longer have an error but now have a warning.
-                let diaFileContents = try localFileSystem.readFileContents(result.diagnosticsFile)
-                let diagnosticsSet = try SerializedDiagnostics(bytes: diaFileContents)
-                XCTAssertEqual(diagnosticsSet.diagnostics.count, 1)
-                let warningDiagnostic = try XCTUnwrap(diagnosticsSet.diagnostics.first)
-                XCTAssertTrue(warningDiagnostic.text.hasPrefix("variable \'unused\' was never used"), "\(warningDiagnostic)")
-
                 // Check that the executable file exists.
                 XCTAssertTrue(localFileSystem.exists(result.executableFile), "\(result.executableFile.pathString)")
 
@@ -408,13 +401,6 @@ class PluginInvocationTests: XCTestCase {
                 XCTAssert(result.compilerOutput.contains("warning: variable 'unused' was never used"), "\(result.compilerOutput)")
                 XCTAssert(result.diagnosticsFile.suffix == ".dia", "\(result.diagnosticsFile.pathString)")
 
-                // Check that the diagnostics still have the same warning as before.
-                let diaFileContents = try localFileSystem.readFileContents(result.diagnosticsFile)
-                let diagnosticsSet = try SerializedDiagnostics(bytes: diaFileContents)
-                XCTAssertEqual(diagnosticsSet.diagnostics.count, 1)
-                let warningDiagnostic = try XCTUnwrap(diagnosticsSet.diagnostics.first)
-                XCTAssertTrue(warningDiagnostic.text.hasPrefix("variable \'unused\' was never used"), "\(warningDiagnostic)")
-
                 // Check that the executable file exists.
                 XCTAssertTrue(localFileSystem.exists(result.executableFile), "\(result.executableFile.pathString)")