[Dependency Scanning] Upon scan failure, ensure scanner diagnostics are emitted

Author: artemcm

Sources/SwiftDriver/ExplicitModuleBuilds/ModuleDependencyScanning.swift

@@ -27,7 +27,7 @@ extension Diagnostic.Message {
     .warning("Fallback to `swift-frontend` dependency scanner invocation")
   }
   static func scanner_diagnostic_error(_ message: String) -> Diagnostic.Message {
-    .error("Dependency scanning failure: \(message)")
+    .error(message)
   }
   static func scanner_diagnostic_warn(_ message: String) -> Diagnostic.Message {
     .warning(message)
@@ -205,11 +205,15 @@ public extension Driver {
                                                 useResponseFiles: .disabled,
                                                 using: executor.resolver)
       Self.sanitizeCommandForLibScanInvocation(&command)
-      imports =
-        try interModuleDependencyOracle.getImports(workingDirectory: cwd,
-                                                   moduleAliases: moduleOutputInfo.aliases,
-                                                   commandLine: command)
-
+      do {
+        imports = try interModuleDependencyOracle.getImports(workingDirectory: cwd,
+                                                             moduleAliases: moduleOutputInfo.aliases,
+                                                             commandLine: command)
+      } catch let DependencyScanningError.dependencyScanFailed(reason) {
+        try emitScannerDiagnostics()
+        throw DependencyScanningError.dependencyScanFailed(reason)
+      }
+      try emitScannerDiagnostics()
     } else {
       // Fallback to legacy invocation of the dependency scanner with
       // `swift-frontend -scan-dependencies -import-prescan`
@@ -222,6 +226,26 @@ public extension Driver {
     return imports
   }
 
+  mutating internal func emitScannerDiagnostics() throws {
+    let possibleDiags = try interModuleDependencyOracle.getScannerDiagnostics()
+    if let diags = possibleDiags {
+      for diagnostic in diags {
+        switch diagnostic.severity {
+        case .error:
+          diagnosticEngine.emit(.scanner_diagnostic_error(diagnostic.message))
+        case .warning:
+          diagnosticEngine.emit(.scanner_diagnostic_warn(diagnostic.message))
+        case .note:
+          diagnosticEngine.emit(.scanner_diagnostic_note(diagnostic.message))
+        case .remark:
+          diagnosticEngine.emit(.scanner_diagnostic_remark(diagnostic.message))
+        case .ignored:
+          diagnosticEngine.emit(.scanner_diagnostic_error(diagnostic.message))
+        }
+      }
+    }
+  }
+
   mutating internal func performDependencyScan() throws -> InterModuleDependencyGraph {
     let scannerJob = try dependencyScanningJob()
     let forceResponseFiles = parsedOptions.hasArgument(.driverForceResponseFiles)
@@ -241,27 +265,15 @@ public extension Driver {
                                                 useResponseFiles: .disabled,
                                                 using: executor.resolver)
       Self.sanitizeCommandForLibScanInvocation(&command)
-      dependencyGraph =
-        try interModuleDependencyOracle.getDependencies(workingDirectory: cwd,
-                                                        moduleAliases: moduleOutputInfo.aliases,
-                                                        commandLine: command)
-      let possibleDiags = try interModuleDependencyOracle.getScannerDiagnostics()
-      if let diags = possibleDiags {
-        for diagnostic in diags {
-          switch diagnostic.severity {
-          case .error:
-            diagnosticEngine.emit(.scanner_diagnostic_error(diagnostic.message))
-          case .warning:
-            diagnosticEngine.emit(.scanner_diagnostic_warn(diagnostic.message))
-          case .note:
-            diagnosticEngine.emit(.scanner_diagnostic_note(diagnostic.message))
-          case .remark:
-            diagnosticEngine.emit(.scanner_diagnostic_remark(diagnostic.message))
-          case .ignored:
-            diagnosticEngine.emit(.scanner_diagnostic_error(diagnostic.message))
-          }
-        }
+      do {
+        dependencyGraph = try interModuleDependencyOracle.getDependencies(workingDirectory: cwd,
+                                                                          moduleAliases: moduleOutputInfo.aliases,
+                                                                          commandLine: command)
+      } catch let DependencyScanningError.dependencyScanFailed(reason) {
+        try emitScannerDiagnostics()
+        throw DependencyScanningError.dependencyScanFailed(reason)
       }
+      try emitScannerDiagnostics()
     } else {
       // Fallback to legacy invocation of the dependency scanner with
       // `swift-frontend -scan-dependencies`

Sources/SwiftDriver/SwiftScan/DependencyGraphBuilder.swift

@@ -67,7 +67,7 @@ internal extension SwiftScan {
     // Note, respective indices of the batch scan input and the returned result must be aligned.
     for (index, resultGraphRefOrNull) in resultGraphRefArray.enumerated() {
       guard let resultGraphRef = resultGraphRefOrNull else {
-        throw DependencyScanningError.dependencyScanFailed
+        throw DependencyScanningError.dependencyScanFailed("Unable to produce dependency graph from batch scan result")
       }
       let decodedGraph = try constructGraph(from: resultGraphRef, moduleAliases: moduleAliases)
 

Sources/SwiftDriver/SwiftScan/SwiftScan.swift

@@ -23,7 +23,7 @@ import struct TSCBasic.Diagnostic
 
 public enum DependencyScanningError: Error, DiagnosticData {
   case missingRequiredSymbol(String)
-  case dependencyScanFailed
+  case dependencyScanFailed(String)
   case failedToInstantiateScanner
   case casError(String)
   case missingField(String)
@@ -38,14 +38,14 @@ public enum DependencyScanningError: Error, DiagnosticData {
     switch self {
       case .missingRequiredSymbol(let symbolName):
         return "libSwiftScan missing required symbol: '\(symbolName)'"
-      case .dependencyScanFailed:
-        return "libSwiftScan dependency scan query failed"
+      case .dependencyScanFailed(let reason):
+        return "Dependency scan query failed: `\(reason)`"
       case .failedToInstantiateScanner:
-        return "libSwiftScan failed to create scanner instance"
+        return "Failed to create scanner instance"
       case .casError(let reason):
-        return "libSwiftScan CAS error: \(reason)"
+        return "CAS error: \(reason)"
       case .missingField(let fieldName):
-        return "libSwiftScan scan result missing required field: `\(fieldName)`"
+        return "Scan result missing required field: `\(fieldName)`"
       case .moduleNameDecodeFailure(let encodedName):
         return "Failed to decode dependency module name: `\(encodedName)`"
       case .unsupportedDependencyDetailsKind(let kindRawValue):
@@ -57,7 +57,7 @@ public enum DependencyScanningError: Error, DiagnosticData {
       case .scanningLibraryNotFound(let path):
         return "Dependency Scanning library not found at path: \(path)"
       case .argumentQueryFailed:
-        return "libSwiftScan supported compiler argument query failed"
+        return "Supported compiler argument query failed"
     }
   }
 }
@@ -137,7 +137,7 @@ internal extension swiftscan_diagnostic_severity_t {
 
     let importSetRefOrNull = api.swiftscan_import_set_create(scanner, invocation)
     guard let importSetRef = importSetRefOrNull else {
-      throw DependencyScanningError.dependencyScanFailed
+      throw DependencyScanningError.dependencyScanFailed("Unable to produce import set")
     }
 
     let importSet = try constructImportSet(from: importSetRef, with: moduleAliases)
@@ -165,7 +165,7 @@ internal extension swiftscan_diagnostic_severity_t {
 
     let graphRefOrNull = api.swiftscan_dependency_graph_create(scanner, invocation)
     guard let graphRef = graphRefOrNull else {
-      throw DependencyScanningError.dependencyScanFailed
+      throw DependencyScanningError.dependencyScanFailed("Unable to produce dependency graph")
     }
 
     let dependencyGraph = try constructGraph(from: graphRef, moduleAliases: moduleAliases)
@@ -226,7 +226,7 @@ internal extension swiftscan_diagnostic_severity_t {
                                                                       inputRef,
                                                                       invocationRef)
     guard let batchResultRef = batchResultRefOrNull else {
-      throw DependencyScanningError.dependencyScanFailed
+      throw DependencyScanningError.dependencyScanFailed("Unable to produce batch scan results")
     }
     // Translate `swiftscan_batch_scan_result_t`
     // into `[ModuleDependencyId: [InterModuleDependencyGraph]]`
@@ -326,7 +326,7 @@ internal extension swiftscan_diagnostic_severity_t {
 
     for diagnosticRefOrNull in diagnosticRefArray {
       guard let diagnosticRef = diagnosticRefOrNull else {
-        throw DependencyScanningError.dependencyScanFailed
+        throw DependencyScanningError.dependencyScanFailed("Unable to produce scanner diagnostics")
       }
       let message = try toSwiftString(api.swiftscan_diagnostic_get_message(diagnosticRef))
       let severity = api.swiftscan_diagnostic_get_severity(diagnosticRef)