upgrade AST<->ESTree translation (#4870)

fixes #968

bin/uglifyjs

@@ -235,7 +235,7 @@ if (options.mangle && options.mangle.properties) {
         });
     }
 }
-if (output == "ast") options.output = {
+if (output == "ast" || output == "spidermonkey") options.output = {
     ast: true,
     code: false,
 };
@@ -313,9 +313,11 @@ function run() {
             if (options.parse.acorn) {
                 files = convert_ast(function(toplevel, name) {
                     return require("acorn").parse(files[name], {
+                        ecmaVersion: "latest",
                         locations: true,
                         program: toplevel,
-                        sourceFile: name
+                        sourceFile: name,
+                        sourceType: "module",
                     });
                 });
             } else if (options.parse.spidermonkey) {
@@ -409,14 +411,7 @@ function run() {
             return value;
         }, 2));
     } else if (output == "spidermonkey") {
-        print(JSON.stringify(UglifyJS.minify(result.code, {
-            compress: false,
-            mangle: false,
-            output: {
-                ast: true,
-                code: false
-            },
-        }).ast.to_mozilla_ast(), null, 2));
+        print(JSON.stringify(result.ast.to_mozilla_ast(), null, 2));
     } else if (output) {
         fs.writeFileSync(output, result.code);
         if (result.map) fs.writeFileSync(output + ".map", result.map);

lib/compress.js

@@ -6562,6 +6562,10 @@ merge(Compressor.prototype, {
                 }
                 return insert_statements(body, node, in_list);
             }
+            if (node instanceof AST_Import) {
+                if (node.properties && node.properties == 0) node.properties = null;
+                return node;
+            }
             if (node instanceof AST_Sequence) {
                 if (node.expressions.length > 1) return;
                 return maintain_this_binding(compressor, tt.parent(), node, node.expressions[0]);

lib/parse.js

@@ -2526,7 +2526,7 @@ function parse($TEXT, options) {
         while (!is("eof"))
             body.push(statement());
         S.input.pop_directives_stack();
-        var end = prev();
+        var end = prev() || start;
         var toplevel = options.toplevel;
         if (toplevel) {
             toplevel.body = toplevel.body.concat(body);

package.json

@@ -23,7 +23,7 @@
     "LICENSE"
   ],
   "devDependencies": {
-    "acorn": "~7.1.0",
+    "acorn": "~8.2.1",
     "semver": "~6.3.0"
   },
   "scripts": {

test/mozilla-ast.js

@@ -11,7 +11,7 @@ function try_beautify(code) {
         mangle: false,
         output: {
             beautify: true,
-            braces: true
+            braces: true,
         }
     });
     if (beautified.error) {
@@ -35,12 +35,18 @@ function validate(ast) {
     return UglifyJS.minify(ast, {
         compress: false,
         mangle: false,
+        validate: true,
     });
 }
 
+function fuzzy(code) {
+    return code.replace(/\bimport\s*\{\s*\}\s*from\s*(['"])/g, "import$1")
+        .replace(/\b(import\b.*?)\s*,\s*\{\s*\}\s*(from\s*['"])/g, "$1 $2");
+}
+
 function test(original, estree, description) {
     var transformed = validate(UglifyJS.AST_Node.from_mozilla_ast(estree));
-    if (transformed.error || original !== transformed.code) {
+    if (transformed.error || original !== transformed.code && fuzzy(original) !== fuzzy(transformed.code)) {
         console.log("//=============================================================");
         console.log("// !!!!!! Failed... round", round);
         console.log("// original code");
@@ -72,19 +78,36 @@ for (var round = 1; round <= num_iterations; round++) {
             compress: false,
             mangle: false,
             output: {
-                ast: true
-            }
+                ast: true,
+            },
         });
-        var ok = test(uglified.code, uglified.ast.to_mozilla_ast(), "AST_Node.to_mozilla_ast()");
+        var ok = true;
         try {
-            ok = test(uglified.code, acorn.parse(input), "acorn.parse()") && ok;
+            var estree = uglified.ast.to_mozilla_ast();
         } catch (e) {
+            ok = false;
             console.log("//=============================================================");
-            console.log("// acorn parser failed... round", round);
+            console.log("// AST_Node.to_mozilla_ast() failed... round", round);
             console.log(e);
             console.log("// original code");
             console.log(input);
         }
+        if (ok) ok = test(uglified.code, estree, "AST_Node.to_mozilla_ast()");
+        if (ok) try {
+            ok = test(uglified.code, acorn.parse(input, {
+                ecmaVersion: "latest",
+                locations: true,
+                sourceType: "module",
+            }), "acorn.parse()");
+        } catch (e) {
+            if (ufuzz.verbose) {
+                console.log("//=============================================================");
+                console.log("// acorn parser failed... round", round);
+                console.log(e);
+                console.log("// original code");
+                console.log(input);
+            }
+        }
         if (!ok) process.exit(1);
     });
 }

test/ufuzz/index.js

@@ -2045,6 +2045,7 @@ function createVarName(maybe, dontStore) {
 if (require.main !== module) {
     exports.createTopLevelCode = createTopLevelCode;
     exports.num_iterations = num_iterations;
+    exports.verbose = verbose;
     return;
 }
 

tools/node.js

@@ -56,6 +56,9 @@ if (+process.env["UGLIFY_BUG_REPORT"]) exports.minify = function(files, options)
 
 function describe_ast() {
     var out = OutputStream({ beautify: true });
+    doitem(AST_Node);
+    return out.get() + "\n";
+
     function doitem(ctor) {
         out.print("AST_" + ctor.TYPE);
         var props = ctor.SELF_PROPS.filter(function(prop) {
@@ -86,9 +89,7 @@ function describe_ast() {
                 });
             });
         }
-    };
-    doitem(AST_Node);
-    return out + "\n";
+    }
 }
 
 function infer_options(options) {