Add config option 'forceParse'

[maxsam4]

Currently, if deepSkip is enabled, all the contracts that are skipped are not post processed to remove stuff like view modifiers. This leads to compilation failures when the skipped contract has a view function and the interface it inherits is not skipped.

Assume there is an interface Imodule and it is implemented by IfirstModule and IsecondModule. Let the interface define a view function that both the modules implement. The compilation will fail after instrumenting if we exclude any one of the module as the interface will be processed to convert view functions to non-payable but the skipped module will still implement it as view function.

We can avoid this by setting deepSkip to true but then large contracts like OraclizeAPI and other unneeded stuff is processed as well which causes other issues (Timeouts, instrumenting hangs sometimes etc).

I propose that we add a config variable forceParse which will be an array like skipFiles and entries in it will be force parsed even if deepSkip is set to true.

Alternatively, we can make deepSkip an array and skip only the files in that array.
I prefer the first option as it won't require unaffected users to change their config.

Update: I have created a PR to fix this.

[cgewecke]

@maxsam4 Thanks so much for your PR and for your excellent description of the issue here.
In 0.6.0 the preprocessing algo has been improved - the older oraclize contract which used to take 30 minutes to instrument now takes ~1 sec.

Additionally, am going to try some changes this month that should remove the necessity of preprocessing for view and pure altogether - I think that's the best way forward in the long run.

Leaving this open for further consideration - it's a nice solution.

[cgewecke]

0.7.0 has resolved all this by using a completely different architecture.