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50 lines
1.3 KiB
XML
50 lines
1.3 KiB
XML
<!DOCTYPE qhelp PUBLIC
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"-//Semmle//qhelp//EN"
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"qhelp.dtd">
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<qhelp>
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<overview>
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<p>
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A value is assigned to a variable or property, but either that location is never read
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later on, or its value is always overwritten before being read. This means
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that the original assignment has no effect, and could indicate a logic error or
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incomplete code.
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</p>
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</overview>
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<recommendation>
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<p>
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Ensure that you check the control and data flow in the method carefully.
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If a value is really not needed, consider omitting the assignment. Be careful,
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though: if the right-hand side has a side-effect (like performing a method call),
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it is important to keep this to preserve the overall behavior.
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</p>
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</recommendation>
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<example>
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<p>
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In the following example, the return value of the call to <code>send</code> on line 2
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is assigned to the local variable <code>result</code>, but then never used.
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</p>
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<sample src="examples/DeadStoreOfLocal.js" />
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<p>
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Assuming that <code>send</code> returns a status code indicating whether the operation
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succeeded or not, the value of <code>result</code> should be checked, perhaps like this:
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</p>
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<sample src="examples/DeadStoreOfLocalGood.js" />
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</example>
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<references>
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<li>Wikipedia: <a href="http://en.wikipedia.org/wiki/Dead_store">Dead store</a>.</li>
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</references>
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</qhelp>
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