tart set: make --disk-size change idempotent (#698)

...when the size is not changed.

Sources/tart/Commands/Run.swift

@@ -610,7 +610,10 @@ struct VMView: NSViewRepresentable {
 
     // Enable automatic display reconfiguration
     // for guests that support it
-    if #available(macOS 14.0, *) {
+    //
+    // This is disabled for Linux because of poor HiDPI
+    // support, which manifests in fonts being too small
+    if #available(macOS 14.0, *), vm.config.os != .linux {
       machineView.automaticallyReconfiguresDisplay = true
     }
 

Sources/tart/Commands/Set.swift

@@ -16,7 +16,7 @@ struct Set: AsyncParsableCommand {
   @Option(help: "VM display resolution in a format of <width>x<height>. For example, 1200x800")
   var display: VMDisplayConfig?
 
-  @Option(help: ArgumentHelp("Resize the VMs disk to the specified size in GB (note that the disk size can only be increased to avoid losing data",
+  @Option(help: ArgumentHelp("Resize the VMs disk to the specified size in GB (note that the disk size can only be increased to avoid losing data)",
                              discussion: """
                              Disk resizing works on most cloud-ready Linux distributions out-of-the box (e.g. Ubuntu Cloud Images
                              have the \"cloud-initramfs-growroot\" package installed that runs on boot) and on the rest of the

Sources/tart/VMDirectory.swift

@@ -138,13 +138,14 @@ struct VMDirectory: Prunable {
     let diskFileHandle = try FileHandle.init(forWritingTo: diskURL)
     let currentDiskFileLength = try diskFileHandle.seekToEnd()
     let desiredDiskFileLength = UInt64(sizeGB) * 1000 * 1000 * 1000
-    if desiredDiskFileLength <= currentDiskFileLength {
+    if desiredDiskFileLength < currentDiskFileLength {
       let currentLengthHuman = ByteCountFormatter().string(fromByteCount: Int64(currentDiskFileLength))
       let desiredLengthHuman = ByteCountFormatter().string(fromByteCount: Int64(desiredDiskFileLength))
       throw RuntimeError.InvalidDiskSize("new disk size of \(desiredLengthHuman) should be larger " +
         "than the current disk size of \(currentLengthHuman)")
+    } else if desiredDiskFileLength > currentDiskFileLength {
+      try diskFileHandle.truncate(atOffset: desiredDiskFileLength)
     }
-    try diskFileHandle.truncate(atOffset: desiredDiskFileLength)
     try diskFileHandle.close()
   }