From 315d9866026014fb26b58e316f9b34a0239085ed Mon Sep 17 00:00:00 2001
From: Mark Probst <mark.probst@gmail.com>
Date: Mon, 20 Jul 2026 17:16:48 -0400
Subject: [PATCH] fix(dart): keep top-level fromJson/toJson names with
 --from-map (#1719)

Co-Authored-By: gpt-5.6-sol via pi <noreply@openai.com>
---
 .../src/language/Dart/DartRenderer.ts         |  4 +-
 test/languages.ts                             |  8 ++-
 test/unit/dart-method-names.test.ts           | 68 +++++++++++++++++++
 3 files changed, 76 insertions(+), 4 deletions(-)
 create mode 100644 test/unit/dart-method-names.test.ts

diff --git a/packages/quicktype-core/src/language/Dart/DartRenderer.ts b/packages/quicktype-core/src/language/Dart/DartRenderer.ts
index 8a46bd7577..1b0cd45684 100644
--- a/packages/quicktype-core/src/language/Dart/DartRenderer.ts
+++ b/packages/quicktype-core/src/language/Dart/DartRenderer.ts
@@ -117,12 +117,12 @@ export class DartRenderer extends ConvenienceRenderer {
         const encoder = new DependencyName(
             propertyNamingFunction,
             name.order,
-            (lookup) => `${lookup(name)}_${this.toJson}`,
+            (lookup) => `${lookup(name)}_toJson`,
         );
         const decoder = new DependencyName(
             propertyNamingFunction,
             name.order,
-            (lookup) => `${lookup(name)}_${this.fromJson}`,
+            (lookup) => `${lookup(name)}_fromJson`,
         );
         this._topLevelDependents.set(name, { encoder, decoder });
         return [encoder, decoder];
diff --git a/test/languages.ts b/test/languages.ts
index 6bcfd43611..0d214b119e 100644
--- a/test/languages.ts
+++ b/test/languages.ts
@@ -1628,8 +1628,12 @@ export const DartLanguage: Language = {
     skipMiscJSON: true,
     rendererOptions: {},
     // The default is final-props=true; this keeps the mutable-property
-    // code path covered.
-    quickTestRendererOptions: [{ "final-props": "false" }],
+    // code path covered.  The targeted from-map sample also verifies that
+    // the fixture driver can keep calling the top-level JSON string helpers.
+    quickTestRendererOptions: [
+        { "final-props": "false" },
+        ["simple-object.json", { "from-map": "true" }],
+    ],
     sourceFiles: ["src/language/Dart/index.ts"],
 };
 
diff --git a/test/unit/dart-method-names.test.ts b/test/unit/dart-method-names.test.ts
new file mode 100644
index 0000000000..17ed1e35c9
--- /dev/null
+++ b/test/unit/dart-method-names.test.ts
@@ -0,0 +1,68 @@
+import { describe, expect, test } from "vitest";
+
+import {
+    InputData,
+    type RendererOptions,
+    jsonInputForTargetLanguage,
+    quicktype,
+} from "../../packages/quicktype-core/src/index.js";
+
+async function renderDart(
+    rendererOptions: RendererOptions = {},
+): Promise<string[]> {
+    const jsonInput = jsonInputForTargetLanguage("dart");
+    await jsonInput.addSource({
+        name: "Sensordata",
+        samples: ['{"sensor":"temp","data":[1,2,3]}'],
+    });
+
+    const inputData = new InputData();
+    inputData.addInput(jsonInput);
+
+    const result = await quicktype({
+        inputData,
+        lang: "dart",
+        rendererOptions,
+    });
+    return result.lines;
+}
+
+describe("Dart JSON method names", () => {
+    test("from-map only renames class-level map methods", async () => {
+        const lines = await renderDart({ "from-map": "true" });
+
+        expect(lines).toContain(
+            "Sensordata sensordataFromJson(String str) => Sensordata.fromMap(json.decode(str));",
+        );
+        expect(lines).toContain(
+            "String sensordataToJson(Sensordata data) => json.encode(data.toMap());",
+        );
+        expect(lines).toContain(
+            "    factory Sensordata.fromMap(Map<String, dynamic> json) => Sensordata(",
+        );
+        expect(lines).toContain("    Map<String, dynamic> toMap() => {");
+        expect(lines.some((line) => line.includes("sensordataFromMap"))).toBe(
+            false,
+        );
+        expect(lines.some((line) => line.includes("sensordataToMap"))).toBe(
+            false,
+        );
+    });
+
+    test("uses Json names at both levels by default", async () => {
+        const lines = await renderDart();
+
+        expect(lines).toContain(
+            "Sensordata sensordataFromJson(String str) => Sensordata.fromJson(json.decode(str));",
+        );
+        expect(lines).toContain(
+            "String sensordataToJson(Sensordata data) => json.encode(data.toJson());",
+        );
+        expect(lines).toContain(
+            "    factory Sensordata.fromJson(Map<String, dynamic> json) => Sensordata(",
+        );
+        expect(lines).toContain("    Map<String, dynamic> toJson() => {");
+        expect(lines.some((line) => line.includes("fromMap"))).toBe(false);
+        expect(lines.some((line) => line.includes("toMap"))).toBe(false);
+    });
+});