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Re: [libvirt] [PATCH] secret_driver.c: remove dead cleanup code



On Mon, Jan 18, 2010 at 10:53:31AM +0100, Jim Meyering wrote:
> Here's another example of appropriate use of assert.
> The while loop removed below is currently guaranteed never
> to be executed, since "list" is always NULL at that point.
> However, you can argue that simply removing the loop is a little
> risky: what if someone changes things to "goto cleanup" before
> "list" reaches the final NULL?  That's why I added the assertion:
> to catch the potential (albeit unlikely) future coding error.

I don't really consider that a net win. If we leave the current code in
there and someone adds a 'goto cleanup' in future  enhancement, then 
everything will work as design. If we replace the current code with an
assert, then it will abort(), or silently do nothing & thus leak if 
compiled with -DNDEBUG.

So while this is technically dead code at this time I don't think we 
should be removing it from the cleanup: block. The cleanup: blocks 
should be pessimistic about considering what has been cleaned up already,
even if this results in possible dead code warnings. We've had many 
actual bugs from cleanup: blocks not free'ing stuff they should have 
done, many of those introduced after refactorings of original code. 

I realize this means that some automated code checkers like Coverity
will always complain about certain things, but these are not actual
bugs. 

Daniel
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