fix: partial method gen couldn't use no accessiblity

docs/wiki/Code-Writer.md

@@ -518,6 +518,10 @@ one. Set the defaults on `GenerationSettings` (to apply across a generation) or
 (to override per writer). Each value is `null`-able, so setting a kind back to `null` omits the
 modifier entirely.
 
+Partial methods are the one exception to method defaulting: `PartialMethod(...)` and any method
+declaration with `IsPartial = true` omit the accessibility modifier when none is provided, even if
+`DefaultMethodAccessibility` is still `Public`.
+
 | Setting | Default |
 |---|---|
 | `DefaultTypeAccessibility` | `Public` |

package.json

@@ -1,6 +1,6 @@
 {
   "name": "purview-sourcegenerator-framework",
-  "version": "1.0.0-prerelease.44",
+  "version": "1.0.0-prerelease.45",
   "license": "MIT",
   "author": {
     "name": "Kieron Lanning",

src/src/SourceGeneratorShared/CodeWriter.DeclarationOverloads.cs

@@ -64,7 +64,10 @@ Action<CodeWriter> writeBody
 	/// </summary>
 	/// <param name="name">The method name.</param>
 	/// <param name="returnType">The return type, or <see langword="null"/> for <c>void</c>.</param>
-	/// <param name="accessibility">The optional accessibility.</param>
+	/// <param name="accessibility">
+	/// The optional accessibility. When omitted, the partial method is emitted without an accessibility
+	/// modifier.
+	/// </param>
 	/// <param name="configure">An optional callback that configures the declaration.</param>
 	/// <returns>The current writer.</returns>
 	/// <example><code>writer.PartialMethod("OnChanged");</code></example>

src/src/SourceGeneratorShared/CodeWriter.cs

@@ -236,8 +236,10 @@ public CodeWriter(
 
 	/// <summary>
 	/// Gets or sets the default accessibility emitted for method declarations when a declaration does not
-	/// specify one. The default is <see cref="TypeDeclarationAccessibility.Public"/>. Set to
-	/// <see langword="null"/> to omit the modifier.
+	/// specify one. The default is <see cref="TypeDeclarationAccessibility.Public"/>. Partial methods are
+	/// the exception: when their declaration does not specify an accessibility, the modifier is omitted
+	/// instead of using this default. Set to <see langword="null"/> to omit the modifier for other method
+	/// declarations.
 	/// </summary>
 	public TypeDeclarationAccessibility? DefaultMethodAccessibility { get; set; } = TypeDeclarationAccessibility.Public;
 
@@ -727,6 +729,11 @@ BlockScope MethodScope(MethodDeclarationOptions declaration, Action<CodeWriter>?
 
 	void MethodHeader(MethodDeclarationOptions declaration)
 	{
+		var accessibility =
+			declaration.IsPartial && declaration.Accessibility is null
+				? null
+				: ResolveAccessibility(declaration.Accessibility, DefaultMethodAccessibility);
+
 		ValidateMethodDeclaration(declaration);
 		BeginWrittenItem(WrittenItemKind.Method);
 
@@ -737,7 +744,7 @@ void MethodHeader(MethodDeclarationOptions declaration)
 		Attributes(declaration.ReturnAttributes, defaultTarget: "return");
 
 		MemberModifiers(
-			ResolveAccessibility(declaration.Accessibility, DefaultMethodAccessibility),
+			accessibility,
 			declaration.IsStatic,
 			declaration.IsAbstract,
 			declaration.IsVirtual,
@@ -759,6 +766,9 @@ void MethodHeader(MethodDeclarationOptions declaration)
 
 	/// <summary>
 	/// Writes a structured partial method declaration.
+	/// When <see cref="MethodDeclarationOptions.Accessibility"/> is <see langword="null"/>, the
+	/// declaration omits any accessibility modifier instead of using
+	/// <see cref="DefaultMethodAccessibility"/>.
 	/// </summary>
 	/// <example><code>writer.PartialMethod(new MethodDeclarationOptions("OnChanged"));</code></example>
 	public CodeWriter PartialMethod(MethodDeclarationOptions declaration)

src/src/SourceGeneratorShared/GenerationSettings.cs

@@ -141,8 +141,10 @@ public GenerationSettings(
 
 	/// <summary>
 	/// Gets the default accessibility emitted for method declarations when a declaration does not specify
-	/// one. The default is <see cref="TypeDeclarationAccessibility.Public"/>. Set to
-	/// <see langword="null"/> to omit the modifier, matching the previous behaviour.
+	/// one. The default is <see cref="TypeDeclarationAccessibility.Public"/>. Partial methods are the
+	/// exception: when their declaration does not specify an accessibility, the modifier is omitted
+	/// instead of using this default. Set to <see langword="null"/> to omit the modifier for other
+	/// method declarations, matching the previous behaviour.
 	/// </summary>
 	public TypeDeclarationAccessibility? DefaultMethodAccessibility { get; init; } =
 		TypeDeclarationAccessibility.Public;

src/tests/SourceGeneratorShared.UnitTests/CodeWriterTests.cs

@@ -3535,7 +3535,7 @@ await Assert
 			.That(writer.ToString())
 			.IsEqualTo(
 				GeneratedAttributes()
-					+ "public readonly partial void OnValidate(global::System.Guid id, string? displayName, bool isActive);\n"
+					+ "readonly partial void OnValidate(global::System.Guid id, string? displayName, bool isActive);\n"
 			);
 	}
 
@@ -3550,7 +3550,7 @@ public async Task PartialMethod_GivenIsReadOnlyFalse_OmitsReadonlyModifier()
 		writer.PartialMethod(declaration);
 
 		// Assert
-		await Assert.That(writer.ToString()).IsEqualTo(GeneratedAttributes() + "public partial void Apply();\n");
+		await Assert.That(writer.ToString()).IsEqualTo(GeneratedAttributes() + "partial void Apply();\n");
 	}
 
 	[Test]
@@ -4654,7 +4654,33 @@ public async Task PartialMethodOverload_GivenMinimalProperties_WritesPartialMeth
 		writer.PartialMethod("OnChanged", Type("void"));
 
 		// Assert
-		await Assert.That(writer.ToString()).IsEqualTo(GeneratedAttributes() + "public partial void OnChanged();\n");
+		await Assert.That(writer.ToString()).IsEqualTo(GeneratedAttributes() + "partial void OnChanged();\n");
+	}
+
+	[Test]
+	public async Task PartialMethod_WithoutAccessibility_OmitsDefaultMethodAccessibility()
+	{
+		// Arrange
+		var writer = CodeWriterFactory.ForTests();
+
+		// Act
+		writer.PartialMethod(new("OnChanged"));
+
+		// Assert
+		await Assert.That(writer.ToString()).IsEqualTo(GeneratedAttributes() + "partial void OnChanged();\n");
+	}
+
+	[Test]
+	public async Task PartialMethod_ExplicitAccessibility_OverridesOmittedDefault()
+	{
+		// Arrange
+		var writer = CodeWriterFactory.ForTests();
+
+		// Act
+		writer.PartialMethod(new("OnChanged", TypeDeclarationAccessibility.Internal));
+
+		// Assert
+		await Assert.That(writer.ToString()).IsEqualTo(GeneratedAttributes() + "internal partial void OnChanged();\n");
 	}
 
 	[Test]