[Xamarin.Android.Tools.AndroidSdk] Provide more logging

Context: dotnet/android#7073
Context: https://github.com/xamarin/xamarin-android/blob/fdfc4c44ba65fcff9caf809bcf2d1f1a6837b1e3/src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/AndroidDependenciesTests.cs#L19-L50

Trying to figure out how xamarin-android's
`AndroidDependenciesTests.InstallAndroidDependenciesTest()` *passes*;
it creates an empty "SDK" directory, then builds with the
`InstallAndroidDependencies` target, and on main this works,
*even though* it implies that it's creating an `AndroidSdkInfo`
instance with an *empty* SDK directory:

	if (Directory.Exists (sdkPath))
		Directory.Delete (sdkPath, true);
	Directory.CreateDirectory (sdkPath);
	// `sdkPath` is not otherwise populated

Yet it *passes* `ValidateAndroidSdkLocation()`:

	  ValidateAndroidSdkLocation: `/Users/runner/work/1/a/TestRelease/06-09_22.00.22/temp/InstallAndroidDependenciesTest/android-sdk`, result=True

I do not understand *how* this can be the case, as
`ValidateAndroidSdkLocation()` wants a `platform-tools/adb` program,
*which should not exist*, yet it validates

I am thus very confused.

Expand the log messages provided by `AndroidSdkBase` & co. so that
we also log "where" the `loc` parameter is coming from, via a new
`locator` parameter (similar to the `locator` parameter in `JdkInfo`),
and update the "file check" logic so that we log the path of the
detected files.

This way, hopefully, I can verify that it *is* finding an `adb`,
and *where that file is located*.

Author: jonpryor

src/Xamarin.Android.Tools.AndroidSdk/Sdks/AndroidSdkBase.cs

@@ -26,7 +26,7 @@ public string[] AllAndroidSdks {
 					var dirs = new List<string?> ();
 					dirs.Add (AndroidSdkPath);
 					dirs.AddRange (GetAllAvailableAndroidSdks ());
-					allAndroidSdks = dirs.Where (d => ValidateAndroidSdkLocation (d))
+					allAndroidSdks = dirs.Where (d => ValidateAndroidSdkLocation ("AllAndroidSdks", d))
 						.Select (d => d!)
 						.Distinct ()
 						.ToArray ();
@@ -102,15 +102,15 @@ public virtual void Initialize (string? androidSdkPath = null, string? androidNd
 			NdkStack = GetExecutablePath (AndroidNdkPath, NdkStack);
 		}
 
-		static string? GetValidPath (Func<string?, bool> pathValidator, string? ctorParam, Func<string?> getPreferredPath, Func<IEnumerable<string>> getAllPaths)
+		static string? GetValidPath (Func<string, string?, bool> pathValidator, string? ctorParam, Func<string?> getPreferredPath, Func<IEnumerable<string>> getAllPaths)
 		{
-			if (pathValidator (ctorParam))
+			if (pathValidator ("constructor param", ctorParam))
 				return ctorParam;
 			ctorParam = getPreferredPath ();
-			if (pathValidator (ctorParam))
+			if (pathValidator ("preferred path", ctorParam))
 				return ctorParam;
 			foreach (var path in getAllPaths ()) {
-				if (pathValidator (path)) {
+				if (pathValidator ("all paths", path)) {
 					return path;
 				}
 			}
@@ -119,18 +119,18 @@ public virtual void Initialize (string? androidSdkPath = null, string? androidNd
 
 		string? GetValidNdkPath (string? ctorParam)
 		{
-			if (ValidateAndroidNdkLocation (ctorParam))
+			if (ValidateAndroidNdkLocation ("constructor param", ctorParam))
 				return ctorParam;
 			if (AndroidSdkPath != null) {
 				string bundle = FindBestNDK (AndroidSdkPath);
-				if (Directory.Exists (bundle) && ValidateAndroidNdkLocation (bundle))
+				if (Directory.Exists (bundle) && ValidateAndroidNdkLocation ("within Android SDK", bundle))
 					return bundle;
 			}
 			ctorParam = PreferedAndroidNdkPath;
-			if (ValidateAndroidNdkLocation (ctorParam))
+			if (ValidateAndroidNdkLocation ("preferred path", ctorParam))
 				return ctorParam;
 			foreach (var path in GetAllAvailableAndroidNdks ()) {
-				if (ValidateAndroidNdkLocation (path))
+				if (ValidateAndroidNdkLocation ("all paths", path))
 					return path;
 			}
 			return null;
@@ -255,31 +255,47 @@ IEnumerable<string> GetJavaSdkPaths ()
 		/// <summary>
 		/// Checks that a value is the location of an Android SDK.
 		/// </summary>
-		public bool ValidateAndroidSdkLocation ([NotNullWhen (true)] string? loc)
+		public bool ValidateAndroidSdkLocation (string locator, [NotNullWhen (true)] string? loc)
 		{
-			bool result = !string.IsNullOrEmpty (loc) && ProcessUtils.FindExecutablesInDirectory (Path.Combine (loc, "platform-tools"), Adb).Any ();
-			Logger (TraceLevel.Verbose, $"{nameof (ValidateAndroidSdkLocation)}: `{loc}`, result={result}");
+			bool result = !string.IsNullOrEmpty (loc);
+			if (result) {
+				bool foundAdb = false;
+				foreach (var p in ProcessUtils.FindExecutablesInDirectory (Path.Combine (loc!, "platform-tools"), Adb)) {
+					Logger (TraceLevel.Verbose, $"{nameof (ValidateAndroidSdkLocation)}: for locator={locator}, path=`{loc}`, found adb `{p}`");
+					foundAdb = true;
+				}
+				result = foundAdb;
+			}
+			Logger (TraceLevel.Verbose, $"{nameof (ValidateAndroidSdkLocation)}: for locator={locator}, path=`{loc}`, result={result}");
 			return result;
 		}
 
 		/// <summary>
 		/// Checks that a value is the location of a Java SDK.
 		/// </summary>
-		public virtual bool ValidateJavaSdkLocation ([NotNullWhen (true)] string? loc)
+		public virtual bool ValidateJavaSdkLocation (string locator, [NotNullWhen (true)] string? loc)
 		{
-			bool result = !string.IsNullOrEmpty (loc) && ProcessUtils.FindExecutablesInDirectory (Path.Combine (loc, "bin"), JarSigner).Any ();
-			Logger (TraceLevel.Verbose, $"{nameof (ValidateJavaSdkLocation)}: `{loc}`, result={result}");
+			bool result = !string.IsNullOrEmpty (loc);
+			if (result) {
+				bool foundSigner = false;
+				foreach (var p in ProcessUtils.FindExecutablesInDirectory (Path.Combine (loc!, "bin"), JarSigner)) {
+					Logger (TraceLevel.Verbose, $"{nameof (ValidateJavaSdkLocation)}: for locator={locator}, path=`{loc}`, found jarsigner `{p}`");
+					foundSigner = true;
+				}
+				result = foundSigner;
+			}
+			Logger (TraceLevel.Verbose, $"{nameof (ValidateJavaSdkLocation)}: locator={locator}, path=`{loc}`, result={result}");
 			return result;
 		}
 
 		/// <summary>
 		/// Checks that a value is the location of an Android SDK.
 		/// </summary>
-		public bool ValidateAndroidNdkLocation ([NotNullWhen (true)] string? loc)
+		public bool ValidateAndroidNdkLocation (string locator, [NotNullWhen (true)] string? loc)
 		{
 			bool result = !string.IsNullOrEmpty (loc) &&
 				ProcessUtils.FindExecutablesInDirectory (loc!, NdkStack).Any ();
-			Logger (TraceLevel.Verbose, $"{nameof (ValidateAndroidNdkLocation)}: `{loc}`, result={result}");
+			Logger (TraceLevel.Verbose, $"{nameof (ValidateAndroidNdkLocation)}: for locator={locator}, path=`{loc}`, result={result}");
 			return result;
 		}
 

src/Xamarin.Android.Tools.AndroidSdk/Sdks/AndroidSdkUnix.cs

@@ -51,7 +51,7 @@ public override string? PreferedAndroidSdkPath {
 				if (androidEl != null) {
 					var path = (string?)androidEl.Attribute ("path");
 
-					if (ValidateAndroidSdkLocation (path))
+					if (ValidateAndroidSdkLocation ("preferred path", path))
 						return path;
 				}
 				return null;
@@ -66,7 +66,7 @@ public override string? PreferedAndroidNdkPath {
 				if (androidEl != null) {
 					var path = (string?)androidEl.Attribute ("path");
 
-					if (ValidateAndroidNdkLocation (path))
+					if (ValidateAndroidNdkLocation ("preferred path", path))
 						return path;
 				}
 				return null;
@@ -81,7 +81,7 @@ public override string? PreferedJavaSdkPath {
 				if (javaEl != null) {
 					var path = (string?)javaEl.Attribute ("path");
 
-					if (ValidateJavaSdkLocation (path))
+					if (ValidateJavaSdkLocation ("preferred path", path))
 						return path;
 				}
 				return null;

src/Xamarin.Android.Tools.AndroidSdk/Sdks/AndroidSdkWindows.cs

@@ -145,7 +145,7 @@ protected override IEnumerable<string> GetAllAvailableAndroidNdks ()
 			foreach (var basePath in new string [] {xamarin_private, android_default, vs_default, vs_default32bit, vs_2017_default, cdrive_default})
 				if (Directory.Exists (basePath))
 					foreach (var dir in Directory.GetDirectories (basePath, "android-ndk-r*"))
-						if (ValidateAndroidNdkLocation (dir))
+						if (ValidateAndroidNdkLocation ("Windows known NDK path", dir))
 							yield return dir;
 
 			foreach (var dir in base.GetAllAvailableAndroidNdks ()) {