Don't generate doc for empty files (#310)

Author: fisker

src/__snapshots__/yaml-test-suite.test.ts.snap

@@ -69177,63 +69177,7 @@ exports[`AB8U.yaml: Sequence entry that looks like two with wrong indentation 1`
 
 exports[`AVM7.yaml: Empty Stream 1`] = `
 {
-  "children": [
-    {
-      "children": [
-        {
-          "children": [],
-          "endComments": [],
-          "position": {
-            "end": {
-              "column": 1,
-              "line": 1,
-              "offset": 0,
-            },
-            "start": {
-              "column": 1,
-              "line": 1,
-              "offset": 0,
-            },
-          },
-          "trailingComment": null,
-          "type": "documentHead",
-        },
-        {
-          "children": [],
-          "endComments": [],
-          "position": {
-            "end": {
-              "column": 1,
-              "line": 1,
-              "offset": 0,
-            },
-            "start": {
-              "column": 1,
-              "line": 1,
-              "offset": 0,
-            },
-          },
-          "type": "documentBody",
-        },
-      ],
-      "directivesEndMarker": false,
-      "documentEndMarker": false,
-      "position": {
-        "end": {
-          "column": 1,
-          "line": 1,
-          "offset": 0,
-        },
-        "start": {
-          "column": 1,
-          "line": 1,
-          "offset": 0,
-        },
-      },
-      "trailingComment": null,
-      "type": "document",
-    },
-  ],
+  "children": [],
   "comments": [],
   "position": {
     "end": {

src/options.test.ts

@@ -2,6 +2,9 @@ import { parse } from "./parse.ts";
 
 for (const { type, text } of [
   { type: "mapping", text: "a: 1\na: 2" },
+  // `<<` is a special key in YAML 1.1
+  // https://github.com/eemeli/yaml/blob/main/src/schema/yaml-1.1/merge.ts
+  // { type: "mapping", text: "<<: 1\n<<: 2" },
   { type: "flowMapping", text: `{"a":1,"a":2}` },
   { type: "flowMapping", text: `{"a":1,'a':2}` },
 ]) {

src/parse.ts

@@ -2,13 +2,15 @@ import * as YAML from "yaml";
 import { attachComments } from "./attach.ts";
 import { createRoot } from "./factories/root.ts";
 import Context from "./transforms/context.ts";
+import { transformDocuments } from "./transforms/document.ts";
 import type { ParseOptions, Root } from "./types.ts";
 import { removeFakeNodes } from "./utils/remove-fake-nodes.ts";
 import { updatePositions } from "./utils/update-positions.ts";
 import { YAMLSyntaxError } from "./yaml-syntax-error.ts";
 
 export function parse(text: string, options?: ParseOptions): Root {
   const lineCounter = new YAML.LineCounter();
+  const context = new Context(text, lineCounter);
   const parser = new YAML.Parser(lineCounter.addNewLine);
   const composer = new YAML.Composer({
     keepSourceTokens: true,
@@ -17,24 +19,21 @@ export function parse(text: string, options?: ParseOptions): Root {
     uniqueKeys: options?.uniqueKeys,
     lineCounter,
   });
-  const documentNodes: YAML.Document.Parsed[] = [];
-  const cstTokens: YAML.CST.Token[] = [];
-  const context = new Context(text, lineCounter);
+  const parsedDocuments: YAML.Document.Parsed[] = [];
+  const cstTokens = [...parser.parse(text)];
 
-  for (const cst of parser.parse(text)) {
-    cstTokens.push(cst);
-    for (const doc of composer.next(cst)) {
-      documentNodes.push(throwParseError(doc, context));
+  for (const parsedDocument of composer.compose(cstTokens, true, text.length)) {
+    const { errors } = parsedDocument;
+    if (errors.length > 0) {
+      throw new YAMLSyntaxError(context, errors[0]);
     }
-  }
 
-  for (const doc of composer.end()) {
-    documentNodes.push(throwParseError(doc, context));
+    parsedDocuments.push(parsedDocument);
   }
 
   const root = createRoot(
     context.transformRange([0, text.length]),
-    context.transformDocuments(documentNodes, cstTokens),
+    transformDocuments(parsedDocuments, cstTokens, context),
     context.comments,
   );
 
@@ -44,11 +43,3 @@ export function parse(text: string, options?: ParseOptions): Root {
 
   return root;
 }
-
-function throwParseError(document: YAML.Document.Parsed, context: Context) {
-  const { errors } = document;
-  if (errors.length > 0) {
-    throw new YAMLSyntaxError(context, errors[0]);
-  }
-  return document;
-}

src/transforms/__snapshots__/document.test.ts.snap

@@ -5,14 +5,7 @@ root (1:1 ~ 1:2)
 1 | ·¶
   | ^
 <root>
-  <document>
-    <documentHead>
-
-    </documentHead>
-    <documentBody>
 
-    </documentBody>
-  </document>
 </root>
 `;
 
@@ -21,14 +14,7 @@ root (1:1 ~ 1:1)
 1 | ¶
   | ~
 <root>
-  <document>
-    <documentHead>
 
-    </documentHead>
-    <documentBody>
-
-    </documentBody>
-  </document>
 </root>
 `;
 
@@ -279,14 +265,7 @@ root (1:1 ~ 2:1)
 2 | ¶
   | ^
 <root>
-  <document>
-    <documentHead>
 
-    </documentHead>
-    <documentBody>
-
-    </documentBody>
-  </document>
 </root>
 `;
 

src/transforms/context.ts

@@ -1,17 +1,9 @@
 import type * as YAML from "yaml";
 import type * as YAML_CST from "../cst.ts";
 import { createPosition } from "../factories/position.ts";
-import type {
-  Comment,
-  Content,
-  Document,
-  Point,
-  Position,
-  Range,
-} from "../types.ts";
+import type { Comment, Content, Point, Position, Range } from "../types.ts";
 import { transformComment } from "./comment.ts";
 import { transformContentProperties } from "./content.ts";
-import { transformDocuments } from "./document.ts";
 import {
   transformNode,
   type TransformNodeProperties,
@@ -39,13 +31,6 @@ class Context {
     return createPosition(start, end);
   }
 
-  transformDocuments(
-    documentNodes: YAML.Document.Parsed[],
-    cstTokens: YAML.CST.Token[],
-  ): Document[] {
-    return transformDocuments(documentNodes, cstTokens, this);
-  }
-
   transformNode<T extends YamlNode>(
     node: T,
     props: TransformNodeProperties,

src/transforms/document.ts

@@ -19,7 +19,7 @@ type DocumentData = {
 };
 
 export function transformDocuments(
-  documentNodes: YAML.Document.Parsed[],
+  parsedDocuments: YAML.Document.Parsed[],
   cstTokens: YAML.CST.Token[],
   context: Context,
 ): Document[] {
@@ -57,15 +57,15 @@ export function transformDocuments(
     }
     if (token.type === "document") {
       // istanbul ignore if -- @preserve
-      if (documentNodes.length <= documents.length) {
+      if (parsedDocuments.length <= documents.length) {
         throw new Error(
           `Unexpected document token at ${getPointText(context.transformOffset(token.offset))}`,
         );
       }
       currentDoc = {
         tokensBeforeBody: [...tokensBeforeBody, ...bufferComments],
         cstNode: token,
-        node: documentNodes[documents.length],
+        node: parsedDocuments[documents.length],
         tokensAfterBody: [],
         docEnd: null,
       };
@@ -79,13 +79,7 @@ export function transformDocuments(
       `Unexpected token type: ${token.type} at ${getPointText(context.transformOffset(token.offset))}`,
     );
   }
-  // istanbul ignore if -- @preserve
-  if (documents.length < documentNodes.length) {
-    const errorIndex = documentNodes[documents.length].range[0];
-    throw new Error(
-      `Unexpected document token at ${getPointText(context.transformOffset(errorIndex))}`,
-    );
-  }
+
   if (documents.length > 0 && !documents[documents.length - 1].docEnd) {
     // Append buffered comments to the last document
     const lastDoc = documents[documents.length - 1];
@@ -96,36 +90,6 @@ export function transformDocuments(
   const nodes = documents.map(document => transformDocument(document, context));
 
   if (bufferComments.length === 0) {
-    if (nodes.length === 0) {
-      // Create an empty document if there is no document but comments
-      const emptyDoc: Document = createDocument(
-        createPosition(
-          context.transformOffset(0),
-          context.transformOffset(context.text.length),
-        ),
-        false,
-        false,
-        createDocumentHead(
-          createPosition(
-            context.transformOffset(0),
-            context.transformOffset(context.text.length),
-          ),
-          [],
-          [],
-          null,
-        ),
-        createDocumentBody(
-          createPosition(
-            context.transformOffset(0),
-            context.transformOffset(context.text.length),
-          ),
-          null,
-          [],
-        ),
-        null,
-      );
-      return [emptyDoc];
-    }
     return nodes;
   }