Merge pull request #1795 from cachemeifyoucan/eng/PR-141554457

Author: cachemeifyoucan

Sources/SwiftDriver/ExplicitModuleBuilds/ExplicitDependencyBuildPlanner.swift

@@ -79,8 +79,8 @@ public typealias ExternalTargetModuleDetailsMap = [ModuleDependencyId: ExternalT
   }
 
   /// Supports resolving bridging header pch command from swiftScan.
-  public func supportsBridgingHeaderPCHCommand() throws -> Bool {
-    return try swiftScanOracle.supportsBridgingHeaderPCHCommand()
+  public var supportsBridgingHeaderPCHCommand: Bool {
+    return swiftScanOracle.supportsBridgingHeaderPCHCommand
   }
 
   /// Generate build jobs for all dependencies of the main module.

Sources/SwiftDriver/ExplicitModuleBuilds/InterModuleDependencies/InterModuleDependencyOracle.swift

@@ -118,9 +118,10 @@ public class InterModuleDependencyOracle {
     return swiftScan.supportsBinaryModuleHeaderDependencies || swiftScan.supportsBinaryModuleHeaderDependency
   }
 
-  @_spi(Testing) public func supportsBridgingHeaderPCHCommand() throws -> Bool {
+  @_spi(Testing) public var supportsBridgingHeaderPCHCommand: Bool {
     guard let swiftScan = swiftScanLibInstance else {
-      fatalError("Attempting to query supported scanner API with no scanner instance.")
+      // If no scanner, feature is not supported.
+      return false
     }
     return swiftScan.supportsBridgingHeaderPCHCommand
   }

Sources/SwiftDriver/Jobs/FrontendJobHelpers.swift

@@ -852,8 +852,8 @@ extension Driver {
 
 
   /// If explicit dependency planner supports creating bridging header pch command.
-  public func supportsBridgingHeaderPCHCommand() throws -> Bool {
-    return try explicitDependencyBuildPlanner?.supportsBridgingHeaderPCHCommand() ?? false
+  public var supportsBridgingHeaderPCHCommand: Bool {
+    return explicitDependencyBuildPlanner?.supportsBridgingHeaderPCHCommand ?? false
   }
 
   /// In Explicit Module Build mode, distinguish between main module jobs and intermediate dependency build jobs,

Sources/SwiftDriver/Jobs/GeneratePCHJob.swift

@@ -30,7 +30,7 @@ extension Driver {
 
     var commandLine: [Job.ArgTemplate] = swiftCompilerPrefixArgs.map { Job.ArgTemplate.flag($0) }
 
-    if try supportsBridgingHeaderPCHCommand() {
+    if supportsBridgingHeaderPCHCommand {
       try addExplicitPCHBuildArguments(inputs: &inputs, commandLine: &commandLine)
       addCacheReplayMapping(to: &commandLine)
     } else {