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codeql/javascript/ql/src/Declarations/BuiltinRedefined.ql
2018-11-07 09:32:02 +01:00

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/**
* @name Builtin redefined
* @description Standard library functions can be redefined, but this should be avoided
* since it makes code hard to read and maintain.
* @kind problem
* @problem.severity recommendation
* @id js/builtin-redefinition
* @tags maintainability
* @precision medium
* @deprecated This query is prone to false positives. Deprecated since 1.17.
*/
import javascript
import Definitions
/**
* Holds if `id` is a redefinition of a standard library function that is considered
* acceptable since it merely introduces a local alias to the standard function of
* the same name.
*/
predicate acceptableRedefinition(Identifier id) {
// function(x, y, undefined) { ... }(23, 42)
id.getName() = "undefined" and
exists (ImmediatelyInvokedFunctionExpr iife |
id = iife.getParameter(iife.getInvocation().getNumArgument())
) or
// Date = global.Date
exists (AssignExpr assgn |
id = assgn.getTarget() and
id.getName() = assgn.getRhs().getUnderlyingValue().(PropAccess).getPropertyName()
) or
// var Date = global.Date
exists (VariableDeclarator decl |
id = decl.getBindingPattern() and
id.getName() = decl.getInit().getUnderlyingValue().(PropAccess).getPropertyName()
)
}
from DefiningIdentifier id, string name
where not id.inExternsFile() and
name = id.getName() and
name.regexpMatch("Object|Function|Array|String|Boolean|Number|Math|Date|RegExp|Error|" +
"NaN|Infinity|undefined|eval|parseInt|parseFloat|isNaN|isFinite|" +
"decodeURI|decodeURIComponent|encodeURI|encodeURIComponent") and
not acceptableRedefinition(id)
select id, "Redefinition of " + name + "."