Use yaml package for formatting

This replaces Prettier as the LSP formatting solution with the `yaml`
package. The `yaml` package can format YAML just fine, and we already
have it as a dependency. Prettier is a big dependency.

If people want to use Prettier, other Prettier integrations are probably
better suited for them. For example, the YAML language server doesn’t
respect Prettier configuration files.

This is a proof of concept. I tried to map existing options to the new
implementation. A more ideal solution might be to change the formatting
options.

Refs #933

package.json

@@ -29,9 +29,6 @@
     "type": "git",
     "url": "https://github.com/redhat-developer/yaml-language-server.git"
   },
-  "optionalDependencies": {
-    "prettier": "2.8.7"
-  },
   "dependencies": {
     "ajv": "^8.11.0",
     "lodash": "4.17.21",
@@ -42,7 +39,7 @@
     "vscode-languageserver-types": "^3.16.0",
     "vscode-nls": "^5.0.0",
     "vscode-uri": "^3.0.2",
-    "yaml": "2.2.2"
+    "yaml": "2.4.5"
   },
   "devDependencies": {
     "@microsoft/eslint-formatter-sarif": "3.0.0",
@@ -65,6 +62,7 @@
     "mocha": "9.2.2",
     "mocha-lcov-reporter": "^1.3.0",
     "nyc": "^15.1.0",
+    "prettier": "2.8.7",
     "rimraf": "^3.0.2",
     "sinon": "^9.0.3",
     "sinon-chai": "^3.5.0",

src/languageserver/handlers/settingsHandlers.ts

@@ -96,7 +96,6 @@ export class SettingsHandler {
 
       if (settings.yaml.format) {
         this.yamlSettings.yamlFormatterSettings = {
-          proseWrap: settings.yaml.format.proseWrap || 'preserve',
           printWidth: settings.yaml.format.printWidth || 80,
         };
 

src/languageservice/services/yamlFormatter.ts

@@ -6,17 +6,20 @@
 
 import { Range, Position, TextEdit, FormattingOptions } from 'vscode-languageserver-types';
 import { CustomFormatterOptions, LanguageSettings } from '../yamlLanguageService';
-import * as prettier from 'prettier';
-import { Options } from 'prettier';
-import * as parser from 'prettier/parser-yaml';
+import { parseDocument, ToStringOptions } from 'yaml';
 import { TextDocument } from 'vscode-languageserver-textdocument';
+import { YamlVersion } from '../parser/yamlParser07';
 
 export class YAMLFormatter {
   private formatterEnabled = true;
+  private yamlVersion: YamlVersion = '1.2';
+  private customTags: string[] = [];
 
   public configure(shouldFormat: LanguageSettings): void {
     if (shouldFormat) {
       this.formatterEnabled = shouldFormat.format;
+      this.yamlVersion = shouldFormat.yamlVersion;
+      this.customTags = shouldFormat.customTags;
     }
   }
 
@@ -27,23 +30,26 @@ export class YAMLFormatter {
 
     try {
       const text = document.getText();
+      const doc = parseDocument(text, {
+        version: this.yamlVersion,
+      });
 
-      const prettierOptions: Options = {
-        parser: 'yaml',
-        plugins: [parser],
-
+      const toStringOptions: ToStringOptions = {
         // --- FormattingOptions ---
-        tabWidth: (options.tabWidth as number) || options.tabSize,
+        indent: (options.tabWidth as number) || options.tabSize || 2,
 
         // --- CustomFormatterOptions ---
         singleQuote: options.singleQuote,
-        bracketSpacing: options.bracketSpacing,
-        // 'preserve' is the default for Options.proseWrap. See also server.ts
-        proseWrap: 'always' === options.proseWrap ? 'always' : 'never' === options.proseWrap ? 'never' : 'preserve',
-        printWidth: options.printWidth,
+        flowCollectionPadding: options.bracketSpacing,
+        blockQuote: options.proseWrap === 'always' ? 'folded' : true,
+        lineWidth: Math.max(options.printWidth || 0, 22),
       };
 
-      const formatted = prettier.format(text, prettierOptions);
+      const formatted = doc.toString(toStringOptions);
+
+      if (formatted === text) {
+        return [];
+      }
 
       return [TextEdit.replace(Range.create(Position.create(0, 0), document.positionAt(text.length)), formatted)];
     } catch (error) {

test/formatter.test.ts

@@ -56,7 +56,7 @@ describe('Formatter Tests', () => {
           printWidth: 20,
           proseWrap: 'always',
         });
-        assert.equal(edits[0].newText, 'comments: >\n  test test test\n  test test test\n  test test test\n  test test test\n');
+        assert.equal(edits[0].newText, 'comments: >\n  test test test test\n  test test test test\n  test test test test\n');
       });
 
       it('Formatting uses tabSize', () => {

yarn.lock

@@ -3222,10 +3222,10 @@ yallist@^4.0.0:
   resolved "https://registry.npmjs.org/yallist/-/yallist-4.0.0.tgz"
   integrity sha512-3wdGidZyq5PB084XLES5TpOSRA3wjXAlIWMhum2kRcv/41Sn2emQ0dycQW4uZXLejwKvg6EsvbdlVL+FYEct7A==
 
-yaml@2.2.2:
-  version "2.2.2"
-  resolved "https://registry.yarnpkg.com/yaml/-/yaml-2.2.2.tgz#ec551ef37326e6d42872dad1970300f8eb83a073"
-  integrity sha512-CBKFWExMn46Foo4cldiChEzn7S7SRV+wqiluAb6xmueD/fGyRHIhX8m14vVGgeFWjN540nKCNVj6P21eQjgTuA==
+yaml@2.4.5:
+  version "2.4.5"
+  resolved "https://registry.yarnpkg.com/yaml/-/yaml-2.4.5.tgz#60630b206dd6d84df97003d33fc1ddf6296cca5e"
+  integrity sha512-aBx2bnqDzVOyNKfsysjA2ms5ZlnjSAW2eG3/L5G/CSujfjLJTJsEw1bGw8kCf04KodQWk1pxlGnZ56CRxiawmg==
 
 [email protected], yargs-parser@^20.2.2:
   version "20.2.4"