DMD needs branches

[Russell Lewis]

Walter Bright wrote:
> Russell Lewis wrote:
>> But that is not necessary the fault of the library code themselves. 
>> Perhaps one of them can't use an old compiler because there is a 
>> compiler crash, and one can't use a new compiler because it uses a 
>> syntax (or keyword) that used to be valid but is now not allowed.  If 
>> there was "stable" branch of the older compiler, that included the 
>> bugfix but not the language change, then both libraries would work 
>> together just fine.
> 
> But bugfixes themselves can cause such problems.

Sort of.  Obviously, bugfixes sometimes are buggy - that's just part of 
life.  Fix 'em as you find 'em.  But a bugfix shouldn't break code that 
(from the perspective of the user) seemed to work in the past.  If so, 
then you are doing more than fixing bugs - you are now changing the 
language, and the "stable" release shouldn't do that unless there is a 
Very Good Reason.

(I know, there are pathological cases where the user is depending on the 
buggy output of the compiler, and when you fix it, he complains...but 
those users are much less interesting to me than the well-informed, 
conservative programmer, with a large project, who needs a bugfix but 
who can't pick up the latest changes to the language.)