Remove comment attachment (babel/babel-eslint#736)

* Remove comment attachment

* Simplify error messaging in tests

eslint/babel-eslint-parser/lib/babylon-to-espree/attachComments.js

@@ -1,59 +0,0 @@
-"use strict";
-
-// comment fixes
-module.exports = function(ast, comments, tokens) {
-  if (comments.length) {
-    const firstComment = comments[0];
-    const lastComment = comments[comments.length - 1];
-    // fixup program start
-    if (!tokens.length) {
-      // if no tokens, the program starts at the end of the last comment
-      ast.start = lastComment.end;
-      ast.loc.start.line = lastComment.loc.end.line;
-      ast.loc.start.column = lastComment.loc.end.column;
-
-      if (ast.leadingComments === null && ast.innerComments.length) {
-        ast.leadingComments = ast.innerComments;
-      }
-    } else if (firstComment.start < tokens[0].start) {
-      // if there are comments before the first token, the program starts at the first token
-      const token = tokens[0];
-      // ast.start = token.start;
-      // ast.loc.start.line = token.loc.start.line;
-      // ast.loc.start.column = token.loc.start.column;
-
-      // estraverse do not put leading comments on first node when the comment
-      // appear before the first token
-      if (ast.body.length) {
-        const node = ast.body[0];
-        node.leadingComments = [];
-        const firstTokenStart = token.start;
-        const len = comments.length;
-        for (let i = 0; i < len && comments[i].start < firstTokenStart; i++) {
-          node.leadingComments.push(comments[i]);
-        }
-      }
-    }
-    // fixup program end
-    if (tokens.length) {
-      const lastToken = tokens[tokens.length - 1];
-      if (lastComment.end > lastToken.end) {
-        // If there is a comment after the last token, the program ends at the
-        // last token and not the comment
-        // ast.end = lastToken.end;
-        ast.range[1] = lastToken.end;
-        ast.loc.end.line = lastToken.loc.end.line;
-        ast.loc.end.column = lastToken.loc.end.column;
-      }
-    }
-  } else {
-    if (!tokens.length) {
-      ast.loc.start.line = 1;
-      ast.loc.end.line = 1;
-    }
-  }
-  if (ast.body && ast.body.length > 0) {
-    ast.loc.start.line = ast.body[0].loc.start.line;
-    ast.range[0] = ast.body[0].start;
-  }
-};

eslint/babel-eslint-parser/lib/babylon-to-espree/convertAST.js

@@ -1,7 +1,7 @@
 "use strict";
 
 const t = require("@babel/core").types;
-const convertComments = require("./convertComments");
+const convertProgramNode = require("./convertProgramNode");
 
 module.exports = function(ast, traverse, code) {
   const state = { source: code };
@@ -20,6 +20,8 @@ module.exports = function(ast, traverse, code) {
 
   delete t.VISITOR_KEYS.Property;
   delete t.VISITOR_KEYS.MethodDefinition;
+
+  convertProgramNode(ast);
 };
 
 const astTransformVisitor = {
@@ -31,16 +33,15 @@ const astTransformVisitor = {
     node._babelType = node.type;
 
     if (node.innerComments) {
-      node.trailingComments = node.innerComments;
       delete node.innerComments;
     }
 
     if (node.trailingComments) {
-      convertComments(node.trailingComments);
+      delete node.trailingComments;
     }
 
     if (node.leadingComments) {
-      convertComments(node.leadingComments);
+      delete node.leadingComments;
     }
   },
   exit(path) {

eslint/babel-eslint-parser/lib/babylon-to-espree/convertProgramNode.js

@@ -0,0 +1,40 @@
+"use strict";
+
+module.exports = function(ast) {
+  ast.type = "Program";
+  ast.sourceType = ast.program.sourceType;
+  ast.directives = ast.program.directives;
+  ast.body = ast.program.body;
+  delete ast.program;
+
+  if (ast.comments.length) {
+    const lastComment = ast.comments[ast.comments.length - 1];
+
+    if (!ast.tokens.length) {
+      // if no tokens, the program starts at the end of the last comment
+      ast.start = lastComment.end;
+      ast.loc.start.line = lastComment.loc.end.line;
+      ast.loc.start.column = lastComment.loc.end.column;
+    } else {
+      const lastToken = ast.tokens[ast.tokens.length - 1];
+
+      if (lastComment.end > lastToken.end) {
+        // If there is a comment after the last token, the program ends at the
+        // last token and not the comment
+        ast.range[1] = lastToken.end;
+        ast.loc.end.line = lastToken.loc.end.line;
+        ast.loc.end.column = lastToken.loc.end.column;
+      }
+    }
+  } else {
+    if (!ast.tokens.length) {
+      ast.loc.start.line = 1;
+      ast.loc.end.line = 1;
+    }
+  }
+
+  if (ast.body && ast.body.length > 0) {
+    ast.loc.start.line = ast.body[0].loc.start.line;
+    ast.range[0] = ast.body[0].start;
+  }
+};

eslint/babel-eslint-parser/lib/babylon-to-espree/convertTokens.js

@@ -1,10 +1,10 @@
 "use strict";
 
 const convertTemplateType = require("./convertTemplateType");
-const toToken = require("./toToken");
+const convertToken = require("./convertToken");
 
 module.exports = function(tokens, tt, code) {
   return convertTemplateType(tokens, tt)
     .filter(t => t.type !== "CommentLine" && t.type !== "CommentBlock")
-    .map(t => toToken(t, tt, code));
+    .map(t => convertToken(t, tt, code));
 };

eslint/babel-eslint-parser/lib/babylon-to-espree/index.js

@@ -1,30 +1,11 @@
 "use strict";
 
-const attachComments = require("./attachComments");
+const convertTokens = require("./convertTokens");
 const convertComments = require("./convertComments");
-const toTokens = require("./toTokens");
-const toAST = require("./toAST");
+const convertAST = require("./convertAST");
 
 module.exports = function(ast, traverse, tt, code) {
-  // convert tokens
-  ast.tokens = toTokens(ast.tokens, tt, code);
-
-  // add comments
+  ast.tokens = convertTokens(ast.tokens, tt, code);
   convertComments(ast.comments);
-
-  // transform esprima and acorn divergent nodes
-  toAST(ast, traverse, code);
-
-  // ast.program.tokens = ast.tokens;
-  // ast.program.comments = ast.comments;
-  // ast = ast.program;
-
-  // remove File
-  ast.type = "Program";
-  ast.sourceType = ast.program.sourceType;
-  ast.directives = ast.program.directives;
-  ast.body = ast.program.body;
-  delete ast.program;
-
-  attachComments(ast, ast.comments, ast.tokens);
+  convertAST(ast, traverse, code);
 };

eslint/babel-eslint-parser/test/specs/babel-eslint.js

@@ -4,23 +4,9 @@ const assert = require("assert");
 const babelEslint = require("../..");
 const espree = require("espree");
 const escope = require("eslint-scope");
-const util = require("util");
 const unpad = require("dedent");
 const assertImplementsAST = require("../helpers/assert-implements-ast");
 
-function lookup(obj, keypath, backwardsDepth) {
-  if (!keypath) {
-    return obj;
-  }
-
-  return keypath
-    .split(".")
-    .slice(0, -1 * backwardsDepth)
-    .reduce((base, segment) => {
-      return base && base[segment], obj;
-    });
-}
-
 function parseAndAssertSame(code) {
   code = unpad(code);
   const esAST = espree.parse(code, {
@@ -38,7 +24,6 @@ function parseAndAssertSame(code) {
     loc: true,
     range: true,
     comment: true,
-    attachComment: true,
     ecmaVersion: 2018,
     sourceType: "module",
   });
@@ -46,25 +31,7 @@ function parseAndAssertSame(code) {
     eslintVisitorKeys: true,
     eslintScopeManager: true,
   }).ast;
-  try {
   assertImplementsAST(esAST, babylonAST);
-  } catch (err) {
-    const traversal = err.message.slice(3, err.message.indexOf(":"));
-    err.message += unpad(`
-      espree:
-      ${util.inspect(lookup(esAST, traversal, 2), {
-        depth: err.depth,
-        colors: true,
-      })}
-      babel-eslint:
-      ${util.inspect(lookup(babylonAST, traversal, 2), {
-        depth: err.depth,
-        colors: true,
-      })}
-    `);
-    throw err;
-  }
-  //assert.equal(esAST, babylonAST);
 }
 
 describe("babylon-to-espree", () => {