Separate 'debug' and 'release' builds?
I think it's better to release the version of the software which your developers actually tested; I therefore tend to delete the 'debug' target from the project/makefile, so that there's only one version that can be built (and tested, and debugged, and released).
For a similar reason, I don't use 'assertions' (see also Are assertions always bad? ...).
One person there argued that the reason for a 'debug' version is that it's easier to debug: but, I counter-argued that you may eventually want to support and debug whatever it is you released, and so you need to build a release which you can if necessary debug ... this may mean enabling debug symbols, and disabling some optimizations, even in the 'release' build.
Someone else said that "this is such a bad idea"; it's a policy I evolved some years ago, having been burned by:
- Some developers' testing their debug but not release versions
- Some developers' writing bugs which show up only in the release version
- The company's releasing the release version after inadequate testing (is it ever entirely adequate?)
- Being called on to debug the release version
Since then I've seen more than one other development shop follow this practice (i.e. not have separate debug and release builds).
What's your policy?
Having separate debug and release builds is a good idea, because it does make development easier.
But debug builds should be for development only, not for testing. You test release builds only. And you don't use developers to test those builds, you use testers.
It's a simple policy that gives the best of both worlds, IMO.
Edit: In response to a comment, I think it's obvious that debug and release builds (can) generate different code. Think "-DDEBUG" vs. "-DNDEBUG", and "#if defined(DEBUG)", etc.
So it's vital that you test the code that you end up shipping. If you do generate different code in debug and release builds, that means testing twice - regardless of whether or not it's tested by the same person.
Debug symbols are not that big an issue, however. Always build with debugging symbols, keep a copy of the unstripped binary, but release a stripped binary. As long as you tag each binary with a build number somehow, you should always be able to identify which unstripped binary corresponds to the stripped binary that you have to debug...
How to strip binaries and load symbols in your debugger from an external source is platform-dependent.
This might be minor, but it adds up to what others have said here. One of the advantages of having QA test release builds is that over time the built in debugging and logging capabilities of your software will advance due to the needs of developers who need to figure out why things are going wrong in QA.
The more the developers need to debug release builds, the better tools you'll have later when customers start having issues. Of course, no reason for developers to work on release builds as part of the development cycle.
Also, I don't know any software company that has long enough cycles to afford the overhead of switching QA from debug to release builds halfway through a version's testing period. Having to do a full QA cycle is something that all too often happens pretty rarely.
Our policy is to have developers work on Debug builds, but EVERYONE else (QA, BAs, sales etc) runs the release version. Yesterday I had to fix a bug that only showed up in the release build it, was obvious what was happening simply BECAUSE it only showed up in release
It's first one here in this shop, and I've been here 18 months or so.
Where things get hairy is when the Release build does different things to the debug build - Yes, I have been to Hell and seen this in some very old, very ropy production code.
I see no reason why not to have both if the only difference between the configurations are debug symbols and optimisations.
so you need to build a release which you can if necessary debug ... this may mean enabling debug symbols, and disabling some optimizations, even in the 'release' build.
Ummm... it sounds like you're doing a debug build to me... right?
The part where you went wrong is this statement:
I think it's better to release the version of the software which your developers actually tested
Developers don't test code. Tests test code.
Your unit tests should test ALL build configurations. Do not make your developers work with one hand tied behind their back - let them use all the debugging tools they have at there disposal. A Debug build is one of these.
Regarding asserts: the use of assertions greatly depends on whether or not you program by contract. If you do, then assertions merely check the contract in a debug build.
As per my answer in the linked thread, we also use the same build for debug and release for very similar reasons. The 10%-20% performance gains from the optimiser tend to be very minor when compared to manual optimisations at algorithm level. A single build removes many potential bugs. Specifically;
Uninitialised variables and small buffer overflows may end up with very different results in debug and optimised release builds.
Even with the symbolic information available, debugging an optimised release can be difficult as the object doesn't match the source, e.g. variables may have been optimised out and code may have been re-arranged. Thus bugs reported in tested release builds can be more difficult, and hence time-consuming, to track down.
Having compared unoptimised and optimised builds under automated regression tests, the performance gains provided by the optimisation don't provide enough extra value to have two builds in my case. It is may be worth noting that the software that I develop is very CPU hungry (e.g. creating and manipulating large surface models).