Add configuration service: JSONC parsing, OS paths, layered settings, file watching

packages/core/src/config/index.ts

@@ -1,2 +1,16 @@
-// Placeholder for settings/keybindings loading, JSONC parser, file watcher.
-export const CONFIG_PLACEHOLDER = true;
+// The configuration service (design.md §11, Req 9): a hand-written JSONC
+// parser, the layered (defaults ← user ← workspace) settings service, and
+// its file watching, live reload, and raw keybindings access.
+
+export {
+ parseJsonc,
+ type JsoncFailure,
+ type JsoncParseResult,
+ type JsoncSuccess,
+} from "./jsonc";
+export {
+ createConfigService,
+ type ConfigService,
+ type ConfigServiceDeps,
+ type ConfigServiceFs,
+} from "./service";

packages/core/src/config/jsonc.test.ts

@@ -0,0 +1,165 @@
+import { describe, expect, test } from "bun:test";
+import { parseJsonc } from "./jsonc";
+
+describe("parseJsonc — happy paths", () => {
+ test("parses plain JSON with no comments or trailing commas", () => {
+ const result = parseJsonc('{"a": 1, "b": [1, 2, 3]}');
+ expect(result.ok).toBe(true);
+ if (result.ok) expect(result.value).toEqual({ a: 1, b: [1, 2, 3] });
+ });
+
+ test("empty input is a parse failure (not valid JSON), never throws", () => {
+ const result = parseJsonc("");
+ expect(result.ok).toBe(false);
+ });
+
+ test("whitespace-only input is a parse failure, never throws", () => {
+ const result = parseJsonc(" \n\t ");
+ expect(result.ok).toBe(false);
+ });
+
+ test("strips a line comment", () => {
+ const result = parseJsonc(`{
+ // this is a comment
+ "a": 1
+ }`);
+ expect(result.ok).toBe(true);
+ if (result.ok) expect(result.value).toEqual({ a: 1 });
+ });
+
+ test("strips a trailing line comment after a value", () => {
+ const result = parseJsonc('{"a": 1 // trailing\n}');
+ expect(result.ok).toBe(true);
+ if (result.ok) expect(result.value).toEqual({ a: 1 });
+ });
+
+ test("strips a block comment", () => {
+ const result = parseJsonc('{ /* comment */ "a": 1 }');
+ expect(result.ok).toBe(true);
+ if (result.ok) expect(result.value).toEqual({ a: 1 });
+ });
+
+ test("strips a multi-line block comment", () => {
+ const result = parseJsonc(`{
+ /*
+ * multi
+ * line
+ */
+ "a": 1
+ }`);
+ expect(result.ok).toBe(true);
+ if (result.ok) expect(result.value).toEqual({ a: 1 });
+ });
+
+ test("strips a trailing comma in an object", () => {
+ const result = parseJsonc('{"a": 1, "b": 2,}');
+ expect(result.ok).toBe(true);
+ if (result.ok) expect(result.value).toEqual({ a: 1, b: 2 });
+ });
+
+ test("strips a trailing comma in an array", () => {
+ const result = parseJsonc("[1, 2, 3,]");
+ expect(result.ok).toBe(true);
+ if (result.ok) expect(result.value).toEqual([1, 2, 3]);
+ });
+
+ test("strips a trailing comma across whitespace and a newline", () => {
+ const result = parseJsonc('{\n "a": 1,\n}');
+ expect(result.ok).toBe(true);
+ if (result.ok) expect(result.value).toEqual({ a: 1 });
+ });
+
+ test("strips nested trailing commas in objects and arrays together", () => {
+ const result = parseJsonc('{"a": [1, 2,], "b": {"c": 3,},}');
+ expect(result.ok).toBe(true);
+ if (result.ok) expect(result.value).toEqual({ a: [1, 2], b: { c: 3 } });
+ });
+
+ test("combines comments and trailing commas", () => {
+ const result = parseJsonc(`{
+ // editor settings
+ "editor.tabSize": 2, // spaces
+ /* block */ "editor.insertSpaces": true,
+ }`);
+ expect(result.ok).toBe(true);
+ if (result.ok) {
+ expect(result.value).toEqual({
+ "editor.tabSize": 2,
+ "editor.insertSpaces": true,
+ });
+ }
+ });
+});
+
+describe("parseJsonc — strings survive comment/comma-like content", () => {
+ test("a string containing // is not treated as a comment", () => {
+ const result = parseJsonc('{"url": "https://example.com"}');
+ expect(result.ok).toBe(true);
+ if (result.ok) expect(result.value).toEqual({ url: "https://example.com" });
+ });
+
+ test("a string containing /* is not treated as a comment start", () => {
+ const result = parseJsonc('{"note": "look: /* not a comment */ ok"}');
+ expect(result.ok).toBe(true);
+ if (result.ok) expect(result.value).toEqual({ note: "look: /* not a comment */ ok" });
+ });
+
+ test("a string containing a comma before a closing brace is preserved", () => {
+ const result = parseJsonc('{"note": "a, b,"}');
+ expect(result.ok).toBe(true);
+ if (result.ok) expect(result.value).toEqual({ note: "a, b," });
+ });
+
+ test("an escaped quote inside a string does not end the string early", () => {
+ const result = parseJsonc('{"note": "she said \\"hi\\", // not a comment"}');
+ expect(result.ok).toBe(true);
+ if (result.ok) {
+ expect(result.value).toEqual({ note: 'she said "hi", // not a comment' });
+ }
+ });
+
+ test("a backslash-escaped backslash before a quote does not confuse string end", () => {
+ const result = parseJsonc('{"path": "C:\\\\", "ok": 1}');
+ expect(result.ok).toBe(true);
+ if (result.ok) expect(result.value).toEqual({ path: "C:\\", ok: 1 });
+ });
+});
+
+describe("parseJsonc — failure reporting", () => {
+ test("broken input reports ok:false with a message and a 1-based line/column", () => {
+ const result = parseJsonc("{ this is not json }");
+ expect(result.ok).toBe(false);
+ if (!result.ok) {
+ expect(typeof result.message).toBe("string");
+ expect(result.message.length).toBeGreaterThan(0);
+ expect(result.line).toBeGreaterThanOrEqual(1);
+ expect(result.column).toBeGreaterThanOrEqual(1);
+ }
+ });
+
+ test("an unterminated object reports a failure, not a throw", () => {
+ expect(() => parseJsonc('{"a": 1')).not.toThrow();
+ const result = parseJsonc('{"a": 1');
+ expect(result.ok).toBe(false);
+ });
+
+ test("a stray trailing comma-comment combo that leaves invalid JSON still fails cleanly", () => {
+ const result = parseJsonc('{"a": 1,, "b": 2}');
+ expect(result.ok).toBe(false);
+ });
+
+ test("never throws across a wide variety of garbage input", () => {
+ const garbageInputs = [
+ "{{{{{",
+ "]]]]",
+ '"unterminated string',
+ "/* unterminated block comment",
+ "// just a comment",
+ "null null",
+ "\u0000\u0001",
+ ];
+ for (const input of garbageInputs) {
+ expect(() => parseJsonc(input)).not.toThrow();
+ }
+ });
+});