feat(yaml): Support YAML 1.1 features

.changeset/witty-cherries-visit.md

@@ -0,0 +1,9 @@
+---
+"@kosko/yaml": major
+---
+
+Support the following YAML 1.1 features to match the behavior of [sigs.k8s.io/yaml](https://pkg.go.dev/sigs.k8s.io/yaml).
+
+- Numbers starting with `0` (e.g. `0777`) are interpreted as octal numbers, instead of decimal numbers.
+- YAML 1.2 octal number `0o` prefix is still supported.
+- YAML 1.1 booleans (`yes`, `no`, `on`, `off`, `y`, `n`) are interpreted as booleans, instead of strings.

internal/jest-preset/jest-preset.cjs

@@ -16,7 +16,10 @@ const config = {
     // Remove `file://` prefix from ESM import paths.
     // On Windows, import URL will be like `file:///C:/foo/bar`, so the third
     // `/` has to be removed too.
-    [process.platform === "win32" ? "^file:///(.+)" : "^file://(.+)"]: "$1"
+    [process.platform === "win32" ? "^file:///(.+)" : "^file://(.+)"]: "$1",
+    // It seems Jest doesn't support export maps properly yet. The yaml package
+    // is resolved to the browser version, which doesn't work in Node.js.
+    "^yaml$": "<rootDir>/node_modules/yaml/dist/index.js"
   }
 };
 

packages/yaml/package.json

@@ -45,7 +45,7 @@
     "@kosko/common-utils": "workspace:^",
     "@kosko/log": "workspace:^",
     "fast-safe-stringify": "^2.1.1",
-    "js-yaml": "^4.1.0"
+    "yaml": "^2.4.2"
   },
   "devDependencies": {
     "@kosko/build-scripts": "workspace:^",

packages/yaml/src/__tests__/yaml.ts

@@ -0,0 +1,76 @@
+import { parse } from "../yaml";
+
+test.each([
+  // YAML 1.1
+  { input: "0123", expected: 83 },
+  // YAML 1.2
+  { input: "0o123", expected: 83 },
+  // Decimal
+  { input: "123", expected: 123 },
+  // String
+  { input: `"0123"`, expected: "0123" },
+  // YAML 1.1 in key
+  { input: "0123: value", expected: { 83: "value" } },
+  // YAML 1.2 in key
+  { input: "0o123: value", expected: { 83: "value" } }
+])("octal number: $input -> $expected", ({ input, expected }) => {
+  expect(parse(input)).toEqual([expected]);
+});
+
+test.each([
+  // Yes
+  { input: "yes", expected: true },
+  { input: "Yes", expected: true },
+  { input: "YES", expected: true },
+  // No
+  { input: "no", expected: false },
+  { input: "No", expected: false },
+  { input: "NO", expected: false },
+  // On
+  { input: "on", expected: true },
+  { input: "On", expected: true },
+  { input: "ON", expected: true },
+  // Off
+  { input: "off", expected: false },
+  { input: "Off", expected: false },
+  { input: "OFF", expected: false },
+  // Y
+  { input: "y", expected: true },
+  { input: "Y", expected: true },
+  // N
+  { input: "n", expected: false },
+  { input: "N", expected: false },
+  // Yes in key
+  { input: "yes: value", expected: { true: "value" } },
+  // No in key
+  { input: "no: value", expected: { false: "value" } },
+  // Yes in value
+  { input: "key: yes", expected: { key: true } },
+  // No in value
+  { input: "key: no", expected: { key: false } }
+])("boolean: $input -> $expected", ({ input, expected }) => {
+  expect(parse(input)).toEqual([expected]);
+});
+
+test("anchor", () => {
+  expect(
+    parse(`
+a: &anchor
+  foo: bar
+b: *anchor
+`)
+  ).toEqual([{ a: { foo: "bar" }, b: { foo: "bar" } }]);
+});
+
+test("map merging", () => {
+  expect(
+    parse(`
+a: &src-a
+  a: 1
+b: &src-b
+  b: 2
+result:
+  <<: [*src-a, *src-b]
+`)
+  ).toEqual([{ a: { a: 1 }, b: { b: 2 }, result: { a: 1, b: 2 } }]);
+});

packages/yaml/src/load.ts

@@ -1,4 +1,4 @@
-import { loadAll } from "js-yaml";
+import { parse } from "./yaml";
 import { readFile } from "node:fs/promises";
 import { getResourceModule, ResourceKind } from "./module";
 import logger, { LogLevel } from "@kosko/log";
@@ -67,7 +67,7 @@ export async function loadString(
   options: LoadOptions = {}
 ): Promise<Manifest[]> {
   const { transform = (x) => x } = options;
-  const input = loadAll(content).filter((x) => x != null);
+  const input = parse(content).filter((x) => x != null);
   const manifests: Manifest[] = [];
 
   for (const entry of input) {

packages/yaml/src/yaml.ts

@@ -0,0 +1,56 @@
+import { parseAllDocuments, visit } from "yaml";
+
+const reLegacyOctNum = /^0[0-7]+$/;
+
+// Match all-lowercase, all-uppercase, and title-case variants
+const legacyTrues = new Set(["y", "Y", "yes", "Yes", "YES", "on", "On", "ON"]);
+const legacyFalses = new Set(["n", "N", "no", "No", "NO", "off", "Off", "OFF"]);
+
+/**
+ * The purpose of this function is to match the behavior of [sigs.k8s.io/yaml]
+ * as closely as possible.
+ *
+ * [sigs.k8s.io/yaml] uses [go-yaml](https://github.com/go-yaml/yaml) under the
+ * hood, which supports most of YAML 1.2, but preserves some YAML 1.1 behaviors
+ * for backwards compatibility. You can see [here](https://github.com/go-yaml/yaml?tab=readme-ov-file#compatibility)
+ * for more information.
+ *
+ * [sigs.k8s.io/yaml]: https://pkg.go.dev/sigs.k8s.io/yaml
+ * [go-yaml]: https://github.com/go-yaml/yaml
+ */
+export function parse(content: string): unknown[] {
+  const documents = parseAllDocuments(content, {
+    // Enable map merging
+    merge: true
+  });
+  const results = [];
+
+  for (const doc of documents) {
+    visit(doc, {
+      Scalar(key, node) {
+        if (node.type !== "PLAIN" || !node.source) return;
+
+        // Handle YAML 1.1 octal numbers
+        if (
+          typeof node.value === "number" &&
+          reLegacyOctNum.test(node.source)
+        ) {
+          node.value = parseInt(node.source, 8);
+        }
+
+        // Handle YAML 1.1 booleans
+        if (typeof node.value === "string") {
+          if (legacyTrues.has(node.source)) {
+            node.value = true;
+          } else if (legacyFalses.has(node.source)) {
+            node.value = false;
+          }
+        }
+      }
+    });
+
+    results.push(doc.toJSON());
+  }
+
+  return results;
+}