[RGen] Add two new validators one for arrays one for properties. (#23647)

Changes in this commit:

1. Added a generic array validator that will validate an array using an
inner validator.
2. Added a property validator that validates the following from a
property:
   - Export<Property> attribute is valid.
   - Must be declared partial.
   - Supported platforms shoul be correct for the accessors.
   - Validate each of the accessor selectors if they have been added.

Extra changes:

1. While test the property validator I found out that we were
duplicating errors in nested valiators. There is no need to add a new
strategy when adding a nested validator.
2. Updated some of the error messages in the FieldValidator since we got
one of the descriptors wrong.
3. Added a new string strategy to ensure that the number of ':' is a
selector matches the number of arguments in a method (this includes
getters and setters in properties).

Author: mandel-macaque

src/rgen/Microsoft.Macios.Bindings.Analyzer/Resources.Designer.cs

@@ -393,4 +393,41 @@
         <value>Ignored flag</value>
     </data>
 
+    <!-- RBI0029 -->
+    
+    <data name="RBI0029Description" xml:space="preserve">
+        <value>There is a mismatch between the arguments of a method/property and the number of ':' in a selector.</value>
+    </data>
+    <data name="RBI0029MessageFormat" xml:space="preserve">
+        <value>There is a mismatch between the arguments of '{0}' (found {1}) and the selector '{2}' (found {3})</value>
+        <comment>The {0} is the name of the method or property, {1} is the argument count. {2} is the selector and {3} is its argument count</comment>
+    </data>
+    <data name="RBI0029Title" xml:space="preserve">
+        <value>Selector argument mismatch</value>
+    </data>
+    
+    <!-- RBI0030 -->
+    
+    <data name="RBI0030Description" xml:space="preserve">
+        <value>Field properties must be declared static.</value>
+    </data>
+    <data name="RBI0030MessageFormat" xml:space="preserve">
+        <value>Field properties must be declared static</value>
+    </data>
+    <data name="RBI0030Title" xml:space="preserve">
+        <value>Wrong field declaration</value>
+    </data>
+    
+    <!-- RBI0031 -->
+    
+    <data name="RBI0031Description" xml:space="preserve">
+        <value>Exported properties must be declared partial.</value>
+    </data>
+    <data name="RBI0031MessageFormat" xml:space="preserve">
+        <value>Exported properties must be declared partial</value>
+    </data>
+    <data name="RBI0031Title" xml:space="preserve">
+        <value>Wrong property declaration</value>
+    </data>
+    
 </root>

src/rgen/Microsoft.Macios.Bindings.Analyzer/Resources.resx

@@ -436,4 +436,49 @@ public static class RgenDiagnostics {
 		description: new LocalizableResourceString (nameof (Resources.RBI0028Description), Resources.ResourceManager,
 			typeof (Resources))
 	);
+
+	/// <summary>
+	/// Diagnostic descriptor for when there is a mismatch between the number of arguments in a selector and the expected argument count.
+	/// </summary>
+	internal static readonly DiagnosticDescriptor RBI0029 = new (
+		"RBI0029",
+		new LocalizableResourceString (nameof (Resources.RBI0029Title), Resources.ResourceManager, typeof (Resources)),
+		new LocalizableResourceString (nameof (Resources.RBI0029MessageFormat), Resources.ResourceManager,
+			typeof (Resources)),
+		"Usage",
+		DiagnosticSeverity.Warning,
+		isEnabledByDefault: true,
+		description: new LocalizableResourceString (nameof (Resources.RBI0029Description), Resources.ResourceManager,
+			typeof (Resources))
+	);
+
+	/// <summary>
+	/// Diagnostic descriptor for when a field property has not been marked as static.
+	/// </summary>
+	internal static readonly DiagnosticDescriptor RBI0030 = new (
+		"RBI0030",
+		new LocalizableResourceString (nameof (Resources.RBI0030Title), Resources.ResourceManager, typeof (Resources)),
+		new LocalizableResourceString (nameof (Resources.RBI0030MessageFormat), Resources.ResourceManager,
+			typeof (Resources)),
+		"Usage",
+		DiagnosticSeverity.Warning,
+		isEnabledByDefault: true,
+		description: new LocalizableResourceString (nameof (Resources.RBI0030Description), Resources.ResourceManager,
+			typeof (Resources))
+	);
+
+	/// <summary>
+	/// Diagnostic descriptor for when a property has not been marked as partial.
+	/// </summary>
+	internal static readonly DiagnosticDescriptor RBI0031 = new (
+		"RBI0031",
+		new LocalizableResourceString (nameof (Resources.RBI0031Title), Resources.ResourceManager, typeof (Resources)),
+		new LocalizableResourceString (nameof (Resources.RBI0031MessageFormat), Resources.ResourceManager,
+			typeof (Resources)),
+		"Usage",
+		DiagnosticSeverity.Warning,
+		isEnabledByDefault: true,
+		description: new LocalizableResourceString (nameof (Resources.RBI0031Description), Resources.ResourceManager,
+			typeof (Resources))
+	);
 }

src/rgen/Microsoft.Macios.Bindings.Analyzer/RgenDiagnostics.cs

@@ -195,22 +195,7 @@ public void AddNestedValidator<TField> (
 		Validator<TField> nestedValidator)
 	{
 		var fieldName = GetPropertyName (selector);
-
 		nestedValidators [fieldName] = nestedValidator;
-
-		AddStrategy (selector, nestedValidator.Descriptors, NestedValidation);
-
-		bool NestedValidation (TField? data, RootContext context, out ImmutableArray<Diagnostic> diagnostic, Location? location = null)
-		{
-			diagnostic = [];
-			if (data is null)
-				return true; // null nested = valid
-
-			var nestedErrors = nestedValidator.ValidateAll (data, context);
-			// flatten the diagnostics
-			diagnostic = [.. nestedErrors.SelectMany (x => x.Value)];
-			return nestedErrors.Count == 0;
-		}
 	}
 
 	/// <summary>

src/rgen/Microsoft.Macios.Bindings.Analyzer/Validator.cs

@@ -0,0 +1,56 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+using System.Collections.Immutable;
+using System.Linq;
+using Microsoft.CodeAnalysis;
+using Microsoft.Macios.Generator.Context;
+
+namespace Microsoft.Macios.Bindings.Analyzer.Validators;
+
+/// <summary>
+/// Validator for arrays of items, which validates each item in the array using an inner validator.
+/// </summary>
+/// <typeparam name="T">The type of items in the array to validate.</typeparam>
+class ArrayValidator<T> : Validator<ImmutableArray<T>> {
+	/// <summary>
+	/// Validates that all items in the array are valid using the inner validator.
+	/// </summary>
+	/// <param name="property">The array of items to validate.</param>
+	/// <param name="context">The root context for validation.</param>
+	/// <param name="diagnostics">When this method returns, contains an array of diagnostics if any items are invalid; otherwise, an empty array.</param>
+	/// <param name="location">The code location to be used for the diagnostics.</param>
+	/// <returns><c>true</c> if all items in the array are valid; otherwise, <c>false</c>.</returns>
+	bool AllItemsAreValid (ImmutableArray<T> property, RootContext context,
+		out ImmutableArray<Diagnostic> diagnostics, Location? location = null)
+	{
+		diagnostics = ImmutableArray<Diagnostic>.Empty;
+		var builder = ImmutableArray.CreateBuilder<Diagnostic> ();
+		// loop over all the variables, validate them and collect the diagnostics
+		foreach (var prop in property) {
+			var errors = validator.ValidateAll (prop, context);
+			if (errors.Count > 0) {
+				// flatten and add all the errors in the builder
+				builder.AddRange (errors.SelectMany (x => x.Value));
+			}
+		}
+		diagnostics = builder.ToImmutable ();
+		return diagnostics.Length == 0;
+	}
+
+	/// <summary>
+	/// The validator used internally to validate each of the items in the array.
+	/// </summary>
+	readonly Validator<T> validator;
+
+	/// <summary>
+	/// Initializes a new instance of the <see cref="ArrayValidator{T}"/> class.
+	/// </summary>
+	/// <param name="innerValidator">The validator to use for validating each item in the array.</param>
+	public ArrayValidator (Validator<T> innerValidator)
+	{
+		validator = innerValidator;
+		// add a global strategy that will validate each of the properties in the array
+		AddGlobalStrategy (validator.Descriptors, AllItemsAreValid);
+	}
+}

src/rgen/Microsoft.Macios.Bindings.Analyzer/Validators/ArrayValidator.cs

@@ -6,6 +6,7 @@
 using Microsoft.Macios.Generator.Context;
 using Microsoft.Macios.Generator.DataModel;
 using static Microsoft.Macios.Generator.RgenDiagnostics;
+using static Microsoft.Macios.Bindings.Analyzer.Validators.PropertyStrategies;
 
 namespace Microsoft.Macios.Bindings.Analyzer.Validators;
 using PropertyFlag = ObjCBindings.Property;
@@ -48,30 +49,6 @@ internal static bool SelectorHasNoWhitespace (string? selector, RootContext cont
 			location: location
 		);
 
-	/// <summary>
-	/// Validates that a field property has the partial modifier.
-	/// </summary>
-	/// <param name="property">The property to validate.</param>
-	/// <param name="context">The root context for validation.</param>
-	/// <param name="diagnostics">When this method returns, contains an array of diagnostics if the property is invalid; otherwise, an empty array.</param>
-	/// <param name="location">The code location to be used for the diagnostics.</param>
-	/// <returns><c>true</c> if the property has the partial modifier; otherwise, <c>false</c>.</returns>
-	internal static bool IsPartial (Property property, RootContext context, out ImmutableArray<Diagnostic> diagnostics,
-		Location? location = null)
-		=> ModifiersStrategies.IsPartial (property.Modifiers, RBI0004, out diagnostics, location, property.Name);
-
-	/// <summary>
-	/// Validates that a field property has the static modifier.
-	/// </summary>
-	/// <param name="property">The property to validate.</param>
-	/// <param name="context">The root context for validation.</param>
-	/// <param name="diagnostics">When this method returns, contains an array of diagnostics if the property is invalid; otherwise, an empty array.</param>
-	/// <param name="location">The code location to be used for the diagnostics.</param>
-	/// <returns><c>true</c> if the property has the static modifier; otherwise, <c>false</c>.</returns>
-	internal static bool IsStatic (Property property, RootContext context, out ImmutableArray<Diagnostic> diagnostics,
-		Location? location = null)
-		=> ModifiersStrategies.IsStatic (property.Modifiers, RBI0004, out diagnostics, location, property.Name);
-
 	/// <summary>
 	/// Validates that field property flags are appropriate for field properties.
 	/// Many property flags are ignored when used on fields, and this method validates that only valid flags are used.
@@ -132,62 +109,6 @@ internal static bool FlagsAreValid (Property property, RootContext context,
 		return diagnostics.Length == 0;
 	}
 
-	/// <summary>
-	/// Validates that the field property and its accessors are available on the current platform.
-	/// This method checks platform availability for the property itself, its getter (if present), and its setter (if present).
-	/// </summary>
-	/// <param name="property">The property to validate.</param>
-	/// <param name="context">The root context for validation.</param>
-	/// <param name="diagnostics">When this method returns, contains an array of diagnostics if the property or its accessors are not available on the current platform; otherwise, an empty array.</param>
-	/// <param name="location">The code location to be used for the diagnostics.</param>
-	/// <returns><c>true</c> if the property and all its accessors are available on the current platform; otherwise, <c>false</c>.</returns>
-	internal static bool IsValidPlatform (Property property, RootContext context,
-		out ImmutableArray<Diagnostic> diagnostics, Location? location = null)
-	{
-		diagnostics = ImmutableArray<Diagnostic>.Empty;
-		if (!property.IsField) {
-			// this is a bug, return the diagnostic for it
-			diagnostics = [Diagnostic.Create (
-				RBI0000, // An unexpected error occurred while processing '{0}'. Please fill a bug report at https://github.com/dotnet/macios/issues/new.
-				location: location,
-				messageArgs: property.Name
-			)];
-			return false;
-		}
-
-		// there are several locations in which we need to check if the field is valid for the platform
-		// 1. the property itself
-		// 2. the getter if present
-		// 3. the setter if present
-		if (!SupportedPlatformStrategies.IsValidPlatform (property.SymbolAvailability,
-				context, out diagnostics, property.Name, property.Location)) {
-			return false;
-		}
-
-		var builder = ImmutableArray.CreateBuilder<Diagnostic> ();
-		// if we have a getter or a setter, we want to validate them as well but we will return those merged in the
-		// diagnostics rather than returning false if one of them is invalid
-		var getter = property.GetAccessor (AccessorKind.Getter);
-		if (!getter.IsNullOrDefault) {
-			if (!SupportedPlatformStrategies.IsValidPlatform (getter.SymbolAvailability, context,
-					out var getterDiagnostics,
-					$"{property.Name}.get", getter.Location)) {
-				builder.AddRange (getterDiagnostics);
-			}
-		}
-
-		var setter = property.GetAccessor (AccessorKind.Setter);
-		if (!setter.IsNullOrDefault) {
-			if (!SupportedPlatformStrategies.IsValidPlatform (setter.SymbolAvailability, context,
-					out var setterDiagnostics,
-					$"{property.Name}.set", setter.Location)) {
-				builder.AddRange (setterDiagnostics);
-			}
-		}
-		diagnostics = builder.ToImmutable ();
-		return diagnostics.Length == 0;
-	}
-
 	/// <summary>
 	/// Initializes a new instance of the <see cref="FieldValidator"/> class.
 	/// </summary>
@@ -198,9 +119,9 @@ public FieldValidator () : base (p => p.Location)
 		AddStrategy (p => p.Selector, RBI0019, SelectorHasNoWhitespace);
 
 		// fields have to be partial
-		AddGlobalStrategy (RBI0001, IsPartial);
+		AddGlobalStrategy (RBI0031, IsPartial);
 		// fields have to be static	
-		AddGlobalStrategy (RBI0004, IsStatic);
+		AddGlobalStrategy (RBI0030, IsStatic);
 
 		// ensure that the flags are valid
 		AddGlobalStrategy ([RBI0000, RBI0028], FlagsAreValid);