[build] Add option to skip Mono MDK provisioning (#8993)

The mono related CLI parameters for xaprepare have been updated to make
it possible to skip installation of the Mono MDK via the following:

    make prepare-update-mono PREPARE_AUTOPROVISION=1 PREPARE_AUTOPROVISION_SKIP_MONO=1
    make prepare PREPARE_AUTOPROVISION=1 PREPARE_AUTOPROVISION_SKIP_MONO=1

Unused `ignore-*-mono-version=` parameters have been removed and
replaced with their default values.

Build warnings in the project have also been fixed on macOS.

Makefile

@@ -15,7 +15,7 @@ PREPARE_SCENARIO =
 PREPARE_CI_PR ?= 0
 PREPARE_CI ?= 0
 PREPARE_AUTOPROVISION ?= 0
-PREPARE_IGNORE_MONO_VERSION ?= 1
+PREPARE_AUTOPROVISION_SKIP_MONO ?= 0
 
 _PREPARE_CI_MODE_PR_ARGS = --no-emoji --run-mode=CI
 _PREPARE_CI_MODE_ARGS = $(_PREPARE_CI_MODE_PR_ARGS) -a
@@ -59,6 +59,10 @@ ifneq ($(PREPARE_AUTOPROVISION),0)
 _PREPARE_ARGS += --auto-provision=yes --auto-provision-uses-sudo=yes
 endif
 
+ifneq ($(PREPARE_AUTOPROVISION_SKIP_MONO),0)
+_PREPARE_ARGS += --auto-provision-skip-mono=yes
+endif
+
 ifneq ($(PREPARE_SCENARIO),)
 _PREPARE_ARGS += -s:"$(PREPARE_SCENARIO)"
 endif

build-tools/xaprepare/README.md

@@ -155,8 +155,9 @@ You can append the following parameters to the command line:
    If set to `0` (the default), the utility will take notice of missing/outdated software the build depends on and exit with an error
    should any such condition is detected. Setting the property to `1` will let the utility install the software (installation **may** 
    use `sudo` on Unix so you will need administrator/root credentials for it to work)
- - `PREPARE_IGNORE_MONO_VERSION=0|1`
-   If set to `1` (the default), the utility will not enforce Mono version but rather will use any Mono version you have installed.
+ - `PREPARE_AUTOPROVISION_SKIP_MONO=0|1`
+   If set to `0` (the default), the utility will ensure the Mono MDK is installed.
+   Setting the property to `1` will allow you to skip Mono MDK installation.
  - `V=1`
    Causes the run to output much more information (making output much more messy in the process) to the console. Normally this additional
    information is placed only in the log files generated by the utility.

build-tools/xaprepare/xaprepare/Application/Context.cs

@@ -138,14 +138,9 @@ partial class Context : AppObject
 		public bool AutoProvisionUsesSudo              { get; set; }
 
 		/// <summary>
-		///   Do not terminate session when Mono is newer than specified in the dependencies
+		///   Skip automatic provision of the Mono MDK if missing
 		/// </summary>
-		public bool IgnoreMaxMonoVersion               { get; set; } = true;
-
-		/// <summary>
-		///   Do not terminate session when Mono is older than specified in the dependencies
-		/// </summary>
-		public bool IgnoreMinMonoVersion               { get; set; } = false;
+		public bool AutoProvisionSkipMono              { get; set; } = false;
 
 		/// <summary>
 		///   Current session execution mode. See <see cref="t:ExecutionMode" />

build-tools/xaprepare/xaprepare/Application/MonoPkgProgram.MacOS.cs

@@ -42,8 +42,8 @@ public override async Task<bool> Install ()
 
 		protected override bool CheckWhetherInstalled ()
 		{
-			IgnoreMaximumVersion = Context.Instance.IgnoreMaxMonoVersion;
-			IgnoreMinimumVersion = Context.Instance.IgnoreMinMonoVersion;
+			IgnoreMaximumVersion = true;
+			IgnoreMinimumVersion = false;
 			return base.CheckWhetherInstalled ();
 		}
 
@@ -55,13 +55,15 @@ protected override async Task<bool> DetermineCurrentVersion ()
 			return await base.DetermineCurrentVersion ();
 		}
 
+#pragma warning disable 1998
 		protected override async Task AfterDetect (bool installed)
 		{
 			if (!installed)
 				return;
 
 			AddToInventory ();
 		}
+#pragma warning restore 1998
 
 		public void AddToInventory ()
 		{

build-tools/xaprepare/xaprepare/ConfigAndData/Dependencies/MacOS.cs

@@ -13,11 +13,6 @@ partial class MacOS
 			new HomebrewProgram ("make"),
 			new HomebrewProgram ("ninja"),
 			new HomebrewProgram ("p7zip", "7za"),
-
-			new MonoPkgProgram ("Mono", "com.xamarin.mono-MDK.pkg", new Uri (Context.Instance.Properties.GetRequiredValue (KnownProperties.MonoDarwinPackageUrl))) {
-				MinimumVersion = Context.Instance.Properties.GetRequiredValue (KnownProperties.MonoRequiredMinimumVersion),
-				MaximumVersion = Context.Instance.Properties.GetRequiredValue (KnownProperties.MonoRequiredMaximumVersion),
-			},
 		};
 
 		static readonly HomebrewProgram git = new HomebrewProgram ("git") {
@@ -28,10 +23,19 @@ protected override void InitializeDependencies ()
 		{
 			Dependencies.AddRange (programs);
 
+			if (!Context.Instance.AutoProvisionSkipMono) {
+				Dependencies.Add (
+					new MonoPkgProgram ("Mono", "com.xamarin.mono-MDK.pkg", new Uri (Context.Instance.Properties.GetRequiredValue (KnownProperties.MonoDarwinPackageUrl))) {
+						MinimumVersion = Context.Instance.Properties.GetRequiredValue (KnownProperties.MonoRequiredMinimumVersion),
+						MaximumVersion = Context.Instance.Properties.GetRequiredValue (KnownProperties.MonoRequiredMaximumVersion),
+					}
+				);
+			}
+
 			// Allow using git from $PATH if it has the right version
 			(bool success, string bv) = Utilities.GetProgramVersion (git.Name);
-			if (success && Version.TryParse (bv, out Version gitVersion) &&
-					Version.TryParse (git.MinimumVersion, out Version gitMinVersion)) {
+			if (success && Version.TryParse (bv, out Version? gitVersion) &&
+					Version.TryParse (git.MinimumVersion, out Version? gitMinVersion)) {
 				if (gitVersion < gitMinVersion)
 					Dependencies.Add (git);
 

build-tools/xaprepare/xaprepare/Main.cs

@@ -27,8 +27,7 @@ sealed class ParsedOptions
 			public string? Configuration       { get; set; }
 			public bool AutoProvision          { get; set; }
 			public bool AutoProvisionUsesSudo  { get; set; }
-			public bool IgnoreMaxMonoVersion   { get; set; }
-			public bool IgnoreMinMonoVersion   { get; set; }
+			public bool AutoProvisionSkipMono  { get; set; }
 			public RefreshableComponent RefreshList { get; set; }
 			public IEnumerable<string> AndroidSdkPlatforms { get; set; } = new [] { "latest" };
 		}
@@ -80,7 +79,6 @@ static async Task<int> Run (string[] args)
 			ParsedOptions parsedOptions = new ParsedOptions {
 				AutoProvision         = ParseBoolean (Context.Instance.Properties.GetValue (KnownProperties.AutoProvision)),
 				AutoProvisionUsesSudo = ParseBoolean (Context.Instance.Properties.GetValue (KnownProperties.AutoProvisionUsesSudo)),
-				IgnoreMaxMonoVersion  = ParseBoolean (Context.Instance.Properties.GetValue (KnownProperties.IgnoreMaxMonoVersion)),
 			};
 
 			var opts = new OptionSet {
@@ -103,8 +101,7 @@ static async Task<int> Run (string[] args)
 				"",
 				{"auto-provision=", $"Automatically install software required by .NET for Android", v => parsedOptions.AutoProvision = ParseBoolean (v)},
 				{"auto-provision-uses-sudo=", $"Allow use of sudo(1) when provisioning", v => parsedOptions.AutoProvisionUsesSudo = ParseBoolean (v)},
-				{"ignore-max-mono-version=", $"Ignore the maximum supported Mono version restriction", v => parsedOptions.IgnoreMaxMonoVersion = ParseBoolean (v)},
-				{"ignore-min-mono-version=", $"Ignore the minimum supported Mono version restriction", v => parsedOptions.IgnoreMinMonoVersion = ParseBoolean (v)},
+				{"auto-provision-skip-mono=", $"Do not automatically install the Mono MDK", v => parsedOptions.AutoProvisionSkipMono = ParseBoolean (v)},
 				{"android-sdk-platforms=", "Comma separated list of Android SDK platform levels to be installed or 'latest' or 'all'. Defaults to 'latest' if no value is provided.", v => parsedOptions.AndroidSdkPlatforms = ParseAndroidSdkPlatformLevels (v?.Trim () ?? String.Empty) },
 				"",
 				{"h|help", "Show this help message", v => parsedOptions.ShowHelp = true },
@@ -135,8 +132,7 @@ static async Task<int> Run (string[] args)
 			Context.Instance.DebugFileExtension    = parsedOptions.DebugFileExtension;
 			Context.Instance.AutoProvision         = parsedOptions.AutoProvision;
 			Context.Instance.AutoProvisionUsesSudo = parsedOptions.AutoProvisionUsesSudo;
-			Context.Instance.IgnoreMaxMonoVersion  = parsedOptions.IgnoreMaxMonoVersion;
-			Context.Instance.IgnoreMinMonoVersion  = parsedOptions.IgnoreMinMonoVersion;
+			Context.Instance.AutoProvisionSkipMono = parsedOptions.AutoProvisionSkipMono;
 			Context.Instance.ComponentsToRefresh   = parsedOptions.RefreshList;
 			Context.Instance.AndroidSdkPlatforms   = parsedOptions.AndroidSdkPlatforms;