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JS: generalize and move DeadStoreOfLocal.qhelp to DeadStore.qhelp

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Esben Sparre Andreasen
2018-10-16 11:01:59 +02:00
parent cacb8fdee0
commit 6ee47c437e
2 changed files with 53 additions and 44 deletions
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49
javascript/ql/src/Declarations/DeadStore.qhelp Normal file
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@@ -0,0 +1,49 @@
<!DOCTYPE qhelp PUBLIC
"-//Semmle//qhelp//EN"
"qhelp.dtd">
<qhelp>
<overview>
<p>
A value is assigned to a location, but either that location is never read
later on, or its value is always overwritten before being read. This means
that the original assignment has no effect, and could indicate a logic error or
incomplete code.
</p>
</overview>
<recommendation>
<p>
Ensure that you check the control and data flow in the method carefully.
If a value is really not needed, consider omitting the assignment. Be careful,
though: if the right-hand side has a side-effect (like performing a method call),
it is important to keep this to preserve the overall behavior.
</p>
</recommendation>
<example>
<p>
In the following example, the return value of the call to <code>send</code> on line 2
is assigned to the local variable <code>result</code>, but then never used.
</p>
<sample src="examples/DeadStoreOfLocal.js" />
<p>
Assuming that <code>send</code> returns a status code indicating whether the operation
succeeded or not, the value of <code>result</code> should be checked, perhaps like this:
</p>
<sample src="examples/DeadStoreOfLocalGood.js" />
</example>
<references>
<li>Wikipedia: <a href="http://en.wikipedia.org/wiki/Dead_store">Dead store</a>.</li>
</references>
</qhelp>

48
javascript/ql/src/Declarations/DeadStoreOfLocal.qhelp
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@@ -1,49 +1,9 @@
<!DOCTYPE qhelp PUBLIC
"-//Semmle//qhelp//EN"
"qhelp.dtd">
"-//Semmle//qhelp//EN"
"qhelp.dtd">
<qhelp>
<overview>
<p>
A value is assigned to a local variable, but either that variable is never read
later on, or its value is always overwritten before being read. This means
that the original assignment has no effect, and could indicate a logic error or
incomplete code.
</p>
</overview>
<recommendation>
<include src="DeadStore.qhelp" />
<p>
Ensure that you check the control and data flow in the method carefully.
If a value is really not needed, consider omitting the assignment. Be careful,
though: if the right-hand side has a side-effect (like performing a method call),
it is important to keep this to preserve the overall behavior.
</p>
</recommendation>
<example>
<p>
In the following example, the return value of the call to <code>send</code> on line 2
is assigned to the local variable <code>result</code>, but then never used.
</p>
<sample src="examples/DeadStoreOfLocal.js" />
<p>
Assuming that <code>send</code> returns a status code indicating whether the operation
succeeded or not, the value of <code>result</code> should be checked, perhaps like this:
</p>
<sample src="examples/DeadStoreOfLocalGood.js" />
</example>
<references>
<li>Wikipedia: <a href="http://en.wikipedia.org/wiki/Dead_store">Dead store</a>.</li>
</references>
</qhelp>