Fix mojibake in csharp.ts and factor [JsonInclude] helper

Commit b484198 introduced 590 UTF-8 double-encoded byte sequences in scripts/codegen/csharp.ts (box-drawing characters in section banners and em-dashes in comments). This commit restores the file to a clean UTF-8 encoding and reapplies the intended logic change (removing the unnecessary !propInternal && !propExperimental guards from the reqMod expressions in the four sites that had it).

While here, factor the duplicated propInternal + [JsonInclude] + visibility pattern into a small pushCSharpInternalAttribute helper used by all six property-emission sites in this file, and delete the dead propExperimental declarations that were left over from the original revert hack.

Generated output (SessionEvents.cs, Rpc.cs) is byte-identical to before this commit; the change is purely TypeScript-side cleanup.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: SteveSandersonMS

scripts/codegen/csharp.ts

@@ -1,4 +1,4 @@
-/*---------------------------------------------------------------------------------------------
+/*---------------------------------------------------------------------------------------------
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
@@ -54,9 +54,9 @@ import {
 
 const execFileAsync = promisify(execFile);
 
-// ── C# type rename overrides ────────────────────────────────────────────────
+// ── C# type rename overrides ────────────────────────────────────────────────
 // Map generated class names to shorter public-facing names.
-// Applied to base classes AND their derived variants (e.g., FooBar → Bar, FooBazShell → BarShell).
+// Applied to base classes AND their derived variants (e.g., FooBar → Bar, FooBazShell → BarShell).
 const TYPE_RENAMES: Record<string, string> = {
     PermissionRequestedDataPermissionRequest: "PermissionRequest",
 };
@@ -72,7 +72,7 @@ function applyTypeRename(className: string): string {
     return className;
 }
 
-// ── C# utilities ────────────────────────────────────────────────────────────
+// ── C# utilities ────────────────────────────────────────────────────────────
 
 function escapeXml(text: string): string {
     return text.replace(/&/g, "&amp;").replace(/</g, "&lt;").replace(/>/g, "&gt;");
@@ -177,7 +177,7 @@ function pushRpcMethodXmlDocs(
 const CANCELLATION_TOKEN_DESCRIPTION =
     'The <see cref="CancellationToken"/> to monitor for cancellation requests. The default is <see cref="CancellationToken.None"/>.';
 
-/** Like xmlDocComment but skips XML escaping — use only for codegen-controlled strings that already contain valid XML tags. */
+/** Like xmlDocComment but skips XML escaping — use only for codegen-controlled strings that already contain valid XML tags. */
 function rawXmlDocSummary(text: string, indent: string): string[] {
     const line = ensureTrailingPunctuation(text.trim());
     return [`${indent}/// <summary>${line}</summary>`];
@@ -297,7 +297,7 @@ function failUnmappable(context: string, schema: JSONSchema7): never {
     const summary = JSON.stringify(schema, (key, value) => (key === "description" ? undefined : value)).slice(0, 200);
     throw new Error(
         `C# codegen: cannot map schema to an idiomatic C# type (${context}). ` +
-            `On the runtime side, either tighten the Zod schema to a typed shape, or — if it is genuinely free-form JSON — ` +
+            `On the runtime side, either tighten the Zod schema to a typed shape, or — if it is genuinely free-form JSON — ` +
             `mark it \`.asOpaqueJson()\` so the schema emits \`x-opaque-json: true\` and the codegen maps it to JsonElement. ` +
             `Offending schema (truncated): ${summary}`,
     );
@@ -311,7 +311,7 @@ async function formatCSharpFile(filePath: string): Promise<void> {
     try {
         const projectFile = path.join(REPO_ROOT, "dotnet/src/GitHub.Copilot.SDK.csproj");
         await execFileAsync("dotnet", ["format", projectFile, "--include", filePath]);
-        console.log(`  ✓ Formatted with dotnet format`);
+        console.log(`  ✓ Formatted with dotnet format`);
     } catch {
         // dotnet format not available, skip
     }
@@ -346,7 +346,7 @@ function schemaTypeToCSharp(schema: JSONSchema7, required: boolean, knownTypes:
         const refName = schema.$ref.split("/").pop()!;
         return knownTypes.get(refName) || refName;
     }
-    // Titled union schemas (anyOf with a title) — use the title if it's a known generated type
+    // Titled union schemas (anyOf with a title) — use the title if it's a known generated type
     if (schema.title && schema.anyOf && knownTypes.has(schema.title)) {
         return required ? schema.title : `${schema.title}?`;
     }
@@ -518,9 +518,23 @@ function pushObsoleteAttributes(lines: string[], indent = ""): void {
     lines.push(...obsoleteAttributes(indent));
 }
 
-// ══════════════════════════════════════════════════════════════════════════════
+/**
+ * Emit the `[JsonInclude]` attribute for an internally-marked property and
+ * return the C# access modifier to use for the property declaration.
+ *
+ * `[JsonInclude]` is required because System.Text.Json only auto-(de)serialises
+ * public members by default; without it, the `internal` setter would silently
+ * be skipped.
+ */
+function pushCSharpInternalAttribute(lines: string[], schema: JSONSchema7, indent = "    "): "public" | "internal" {
+    const propInternal = isSchemaInternal(schema);
+    if (propInternal) lines.push(`${indent}[JsonInclude]`);
+    return propInternal ? "internal" : "public";
+}
+
+// ══════════════════════════════════════════════════════════════════════════════
 // SESSION EVENTS
-// ══════════════════════════════════════════════════════════════════════════════
+// ══════════════════════════════════════════════════════════════════════════════
 
 interface EventVariant {
     typeName: string;
@@ -779,12 +793,9 @@ function generateFlattenedBooleanDiscriminatedClass(
         if (isSchemaExperimental(info.schema)) pushExperimentalAttribute(lines, "    ");
         if (isMillisecondsDurationProperty(propName, info.schema)) lines.push(`    [JsonConverter(typeof(MillisecondsTimeSpanConverter))]`);
         if (!isReq) lines.push(`    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]`);
-        const propInternal = isSchemaInternal(info.schema);
-        const propExperimental = isSchemaExperimental(info.schema);
-        if (propInternal) lines.push(`    [JsonInclude]`);
+        const propVisibility = pushCSharpInternalAttribute(lines, info.schema);
         lines.push(`    [JsonPropertyName("${propName}")]`);
         const reqMod = isReq && !csharpType.endsWith("?") ? "required " : "";
-        const propVisibility = propInternal ? "internal" : "public";
         lines.push(`    ${propVisibility} ${reqMod}${csharpType} ${csharpName} { get; set; }`);
     }
 
@@ -887,12 +898,9 @@ function generateDerivedClass(
             if (isSchemaExperimental(prop)) pushExperimentalAttribute(lines, "    ");
             if (isMillisecondsDurationProperty(propName, prop)) lines.push(`    [JsonConverter(typeof(MillisecondsTimeSpanConverter))]`);
             if (!isReq) lines.push(`    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]`);
-            const propInternal = isSchemaInternal(prop);
-            const propExperimental = isSchemaExperimental(prop);
-            if (propInternal) lines.push(`    [JsonInclude]`);
+            const propVisibility = pushCSharpInternalAttribute(lines, prop);
             lines.push(`    [JsonPropertyName("${propName}")]`);
             const reqMod = isReq && !csharpType.endsWith("?") ? "required " : "";
-            const propVisibility = propInternal ? "internal" : "public";
             lines.push(`    ${propVisibility} ${reqMod}${csharpType} ${csharpName} { get; set; }`, "");
         }
     }
@@ -1117,12 +1125,9 @@ function generateNestedClass(
         if (isSchemaExperimental(prop)) pushExperimentalAttribute(lines, "    ");
         if (isMillisecondsDurationProperty(propName, prop)) lines.push(`    [JsonConverter(typeof(MillisecondsTimeSpanConverter))]`);
         if (!isReq) lines.push(`    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]`);
-        const propInternal = isSchemaInternal(prop);
-        const propExperimental = isSchemaExperimental(prop);
-        if (propInternal) lines.push(`    [JsonInclude]`);
+        const propVisibility = pushCSharpInternalAttribute(lines, prop);
         lines.push(`    [JsonPropertyName("${propName}")]`);
         const reqMod = isReq && !csharpType.endsWith("?") ? "required " : "";
-        const propVisibility = propInternal ? "internal" : "public";
         lines.push(`    ${propVisibility} ${reqMod}${csharpType} ${csharpName} { get; set; }`, "");
     }
     if (lines[lines.length - 1] === "") lines.pop();
@@ -1268,12 +1273,9 @@ function generateDataClass(variant: EventVariant, knownTypes: Map<string, string
         if (isSchemaExperimental(prop)) pushExperimentalAttribute(lines, "    ");
         if (isMillisecondsDurationProperty(propName, prop)) lines.push(`    [JsonConverter(typeof(MillisecondsTimeSpanConverter))]`);
         if (!isReq) lines.push(`    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]`);
-        const propInternal = isSchemaInternal(prop);
-        const propExperimental = isSchemaExperimental(prop);
-        if (propInternal) lines.push(`    [JsonInclude]`);
+        const propVisibility = pushCSharpInternalAttribute(lines, prop);
         lines.push(`    [JsonPropertyName("${propName}")]`);
         const reqMod = isReq && !csharpType.endsWith("?") ? "required " : "";
-        const propVisibility = propInternal ? "internal" : "public";
         lines.push(`    ${propVisibility} ${reqMod}${csharpType} ${csharpName} { get; set; }`, "");
     }
     if (lines[lines.length - 1] === "") lines.pop();
@@ -1305,10 +1307,8 @@ function emitSessionEventEnvelopeProperty(
     if (isSchemaExperimental(property.schema)) pushExperimentalAttribute(lines, "    ");
     if (isMillisecondsDurationProperty(property.name, property.schema)) lines.push(`    [JsonConverter(typeof(MillisecondsTimeSpanConverter))]`);
     if (!property.required) lines.push(`    [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingNull)]`);
-    const propInternal = isSchemaInternal(property.schema);
-    if (propInternal) lines.push(`    [JsonInclude]`);
+    const propVisibility = pushCSharpInternalAttribute(lines, property.schema);
     lines.push(`    [JsonPropertyName("${property.name}")]`);
-    const propVisibility = propInternal ? "internal" : "public";
     lines.push(`    ${propVisibility} ${csharpType} ${csharpName} { get; set; }`, "");
 
     return lines;
@@ -1411,13 +1411,13 @@ export async function generateSessionEvents(schemaPath?: string): Promise<void>
     const processed = postProcessSchema(schema);
     const code = generateSessionEventsCode(processed);
     const outPath = await writeGeneratedFile("dotnet/src/Generated/SessionEvents.cs", code);
-    console.log(`  ✓ ${outPath}`);
+    console.log(`  ✓ ${outPath}`);
     await formatCSharpFile(outPath);
 }
 
-// ══════════════════════════════════════════════════════════════════════════════
+// ══════════════════════════════════════════════════════════════════════════════
 // RPC TYPES
-// ══════════════════════════════════════════════════════════════════════════════
+// ══════════════════════════════════════════════════════════════════════════════
 
 let emittedRpcClassSchemas = new Map<string, string>();
 let emittedRpcEnumResultTypes = new Set<string>();
@@ -1524,7 +1524,7 @@ function resolveRpcType(schema: JSONSchema7, isRequired: boolean, parentClassNam
 
         return resolveRpcType(refSchema, isRequired, parentClassName, propName, classes);
     }
-    // Handle anyOf: [T, null/{not:{}}] → T? (nullable typed property)
+    // Handle anyOf: [T, null/{not:{}}] → T? (nullable typed property)
     const nullableInner = getNullableInner(schema);
     if (nullableInner) {
         return resolveRpcType(nullableInner, false, parentClassName, propName, classes);
@@ -1661,8 +1661,7 @@ function emitRpcClass(
         if (isSchemaDeprecated(prop)) pushObsoleteAttributes(lines, "    ");
         if (isSchemaExperimental(prop)) pushExperimentalAttribute(lines, "    ");
         if (isMillisecondsDurationProperty(propName, prop)) lines.push(`    [JsonConverter(typeof(MillisecondsTimeSpanConverter))]`);
-        const propInternal = isSchemaInternal(prop);
-        if (propInternal) lines.push(`    [JsonInclude]`);
+        const propVisibility = pushCSharpInternalAttribute(lines, prop);
         lines.push(`    [JsonPropertyName("${propName}")]`);
 
         let defaultVal = "";
@@ -1680,7 +1679,6 @@ function emitRpcClass(
                 defaultVal = " = null!;";
             }
         }
-        const propVisibility = propInternal ? "internal" : "public";
         lines.push(`    ${propVisibility} ${csharpType} ${csharpName} ${propAccessors}${defaultVal}`);
         if (i < props.length - 1) lines.push("");
     }
@@ -2403,13 +2401,13 @@ export async function generateRpc(schemaPath?: string, sessionEventsSchema?: JSO
     }
     const code = generateRpcCode(schema, externalJsonSerializableRefs, externalValueTypes);
     const outPath = await writeGeneratedFile("dotnet/src/Generated/Rpc.cs", code);
-    console.log(`  ✓ ${outPath}`);
+    console.log(`  ✓ ${outPath}`);
     await formatCSharpFile(outPath);
 }
 
-// ══════════════════════════════════════════════════════════════════════════════
+// ══════════════════════════════════════════════════════════════════════════════
 // MAIN
-// ══════════════════════════════════════════════════════════════════════════════
+// ══════════════════════════════════════════════════════════════════════════════
 
 async function generate(sessionSchemaPath?: string, apiSchemaPath?: string): Promise<void> {
     await generateSessionEvents(sessionSchemaPath);