Friendly decompression error message (#835)

* Friendly decompression error message

* Wrap FilterError

Sources/tart/VMDirectory+OCI.swift

@@ -1,3 +1,4 @@
+import Compression
 import Foundation
 import Sentry
 
@@ -53,8 +54,13 @@ extension VMDirectory {
     let progress = Progress(totalUnitCount: diskCompressedSize)
     ProgressObserver(progress).log(defaultLogger)
 
-    try await diskImplType.pull(registry: registry, diskLayers: layers, diskURL: diskURL, concurrency: concurrency, progress: progress,
-                                localLayerCache: localLayerCache)
+    do {
+      try await diskImplType.pull(registry: registry, diskLayers: layers, diskURL: diskURL,
+                                  concurrency: concurrency, progress: progress,
+                                  localLayerCache: localLayerCache)
+    } catch let error where error is FilterError {
+      throw RuntimeError.PullFailed("failed to decompress disk: \(error.localizedDescription)")
+    }
 
     // Pull VM's NVRAM file layer and store it in an NVRAM file
     defaultLogger.appendNewLine("pulling NVRAM...")

Sources/tart/VMStorageHelper.swift

@@ -69,6 +69,7 @@ enum RuntimeError : Error {
   case OCIStorageError(_ message: String)
   case OCIUnsupportedDiskFormat(_ format: String)
   case SuspendFailed(_ message: String)
+  case PullFailed(_ message: String)
 }
 
 protocol HasExitCode {
@@ -122,6 +123,8 @@ extension RuntimeError : CustomStringConvertible {
       return "OCI disk format \(format) is not supported by this version of Tart"
     case .SuspendFailed(let message):
       return "Failed to suspend the VM: \(message)"
+    case .PullFailed(let message):
+      return message
     }
   }
 }