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TypeError: Cannot read property '_walk' of null #1609

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jsopenrb opened this issue Mar 16, 2017 · 1 comment · Fixed by #1610
Closed

TypeError: Cannot read property '_walk' of null #1609

jsopenrb opened this issue Mar 16, 2017 · 1 comment · Fixed by #1610

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@jsopenrb
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Version: uglify-js 2.8.12
CLI: uglifyjs test.js -c -m

Minimal example:

(function(){
  var C = 'something';

  (function() {
    var v1 = C, v2;
    v2 = somefn(v1);
    v2.prop = v1;
  })();
})();

Error output:

WARN: Dropping unused variable v1 [test.js:5,8]
WARN: Collapsing constant C [test.js:5,13]
undefined:1104
            this.right._walk(visitor);
                      ^

TypeError: Cannot read property '_walk' of null
    at AST_Node.eval (eval at <anonymous> (/usr/lib/node_modules/uglify-js/tools/node.js:28:1), <anonymous>:1104:23)
    at Object._visit (eval at <anonymous> (/usr/lib/node_modules/uglify-js/tools/node.js:28:1), <anonymous>:1340:21)
    at AST_Node._walk (eval at <anonymous> (/usr/lib/node_modules/uglify-js/tools/node.js:28:1), <anonymous>:1102:24)
    at AST_Node.eval (eval at <anonymous> (/usr/lib/node_modules/uglify-js/tools/node.js:28:1), <anonymous>:1041:36)
    at Object._visit (eval at <anonymous> (/usr/lib/node_modules/uglify-js/tools/node.js:28:1), <anonymous>:1340:21)
    at AST_Node._walk (eval at <anonymous> (/usr/lib/node_modules/uglify-js/tools/node.js:28:1), <anonymous>:1039:24)
    at AST_Node.eval (eval at <anonymous> (/usr/lib/node_modules/uglify-js/tools/node.js:28:1), <anonymous>:517:23)
    at Object._visit (eval at <anonymous> (/usr/lib/node_modules/uglify-js/tools/node.js:28:1), <anonymous>:1340:21)
    at AST_Node._walk (eval at <anonymous> (/usr/lib/node_modules/uglify-js/tools/node.js:28:1), <anonymous>:516:24)
    at walk_body (eval at <anonymous> (/usr/lib/node_modules/uglify-js/tools/node.js:28:1), <anonymous>:528:17)
@alexlamsl
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Interesting - disabling either collapse_vars or reduce_vars would avoid this crash - investigating.

alexlamsl added a commit to alexlamsl/UglifyJS that referenced this issue Mar 16, 2017
@alexlamsl
fix chained evaluation
e586bf9 
`reduce_vars` enables substitution of variables but did not clone the value's `AST_Node`.

This confuses `collapse_vars` and result in invalid AST and subsequent crash.

fixes mishoo#1609
@alexlamsl alexlamsl mentioned this issue Mar 16, 2017
Merged
alexlamsl added a commit that referenced this issue Mar 16, 2017
@alexlamsl
fix chained evaluation (#1610)
ac40301 
`reduce_vars` enables substitution of variables but did not clone the value's `AST_Node`.

This confuses `collapse_vars` and result in invalid AST and subsequent crash.

fixes #1609
@KyleCartmell KyleCartmell mentioned this issue Sep 28, 2018
Closed
@kzc kzc mentioned this issue Oct 2, 2018
Closed
@Crashthatch Crashthatch mentioned this issue Oct 10, 2018
Closed
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fix chained evaluation alexlamsl/UglifyJS
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@alexlamsl @jsopenrb