Remove CPP driven error reporting in favor of HasCallStack
#397
Conversation
Co-authored-by: konsumlamm <[email protected]>
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Excellent! I added Also monomophic functions lack HasCallStack constraint which again causes call stack to terminate early: or if it's added: |
Yes, this is the next step. I wanted to keep this PR to a minimum. |
Good catch!! |
Otherwise call stack is terminated early > CallStack (from HasCallStack): > error, called at src/Data/Vector/Internal/Check.hs:101:12 in ... > checkError, called at src/Data/Vector/Internal/Check.hs:107:17 in ... > check, called at src/Data/Vector/Internal/Check.hs:120:5 in ... Compare with > CallStack (from HasCallStack): > error, called at src/Data/Vector/in ... > checkError, called at src/Data/Vector/in ... > check, called at src/Data/Vector/in ... > checkIndex, called at src/Data/Vector/Generic.hs:238:11 in ... > !, called at src/Data/Vector.hs:505:7 in ...
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@Bodigrim Do you have input on this ticket? If not, then I'll merge it tomorrow. |
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@lehins any chance to check performance impact? I guess all these functions are non-recursive and inline well, so there is no associated cost to |
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I did compare benchmarks included in the repo and there was no difference in performance. As you mentioned all these functions inline well, so it is expected that there would be no regressions (also mentioned in this comment by Ben: #184 (comment)) As an extra confirmation I did a similar switch in |
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This is a breaking change, because downstream packages could have included |
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@Bodigrim I beg to differ. There is not a single place in haddock where However, I will add this ticket into changelog before making a release. I am sure there are other things that we have missed that didn't make it into the changelog, so I'll go through all of the PRs since version 0.12 and catalog them with PR numbers in the changelog. (I wish I didn't have to do that and all changelog entries were added together with the PR, but we are all human and it is easy to forget it.) |
# Changes in version 0.13.0.0
* `mkType` from `Data.Vector.Generic` is deprecated in favor of
`Data.Data.mkNoRepType`
* The role signatures on several `Vector` types were too permissive, so they
have been tightened up:
* The role signature for `Data.Vector.Mutable.MVector` is now
`type role MVector nominal representational` (previously, both arguments
were `phantom`). [#224](haskell/vector#224)
* The role signature for `Data.Vector.Primitive.Vector` is now
`type role Vector nominal` (previously, it was `phantom`).
The role signature for `Data.Vector.Primitive.Mutable.MVector` is now
`type role MVector nominal nominal` (previously, both arguments were
`phantom`). [#316](haskell/vector#316)
* The role signature for `Data.Vector.Storable.Vector` is now
`type role Vector nominal` (previous, it was `phantom`), and the signature
for `Data.Vector.Storable.Mutable.MVector` is now
`type role MVector nominal nominal` (previous, both arguments were
`phantom`). [#235](haskell/vector#235)
We pick `nominal` for the role of the last argument instead of
`representational` since the internal structure of a `Storable` vector is
determined by the `Storable` instance of the element type, and it is not
guaranteed that the `Storable` instances between two representationally
equal types will preserve this internal structure. One consequence of this
choice is that it is no longer possible to `coerce` between
`Storable.Vector a` and `Storable.Vector b` if `a` and `b` are nominally
distinct but representationally equal types. We now provide
`unsafeCoerce{M}Vector` and `unsafeCast` functions to allow this (the onus
is on the user to ensure that no `Storable` invariants are broken when
using these functions).
* Methods of type classes `Data.Vector.Generic.Mutable.MVector` and
`Data.Vector.Generic.Vector` use concrete monads (`ST`, etc) istead of being
polymorphic (`PrimMonad`, etc). [#335](haskell/vector#335).
This makes it possible to derive `Unbox` with:
* `GeneralizedNewtypeDeriving`
* via `UnboxViaPrim` and `Prim` instance
* via `As` and `IsoUnbox` instance: [#378](haskell/vector#378)
* Add `MonadFix` instance for boxed vectors: [#312](haskell/vector#312)
* Re-export `PrimMonad` and `RealWorld` from mutable vectors:
[#320](haskell/vector#320)
* Add `maximumOn` and `minimumOn`: [#356](haskell/vector#356)
* The functions `scanl1`, `scanl1'`, `scanr1`, and `scanr1'` for immutable
vectors are now defined when given empty vectors as arguments,
in which case they return empty vectors. This new behavior is consistent
with the one of the corresponding functions in `Data.List`.
Prior to this change, applying an empty vector to any of those functions
resulted in an error. This change was introduced in:
[#382](haskell/vector#382)
* Change allocation strategy for `unfoldrN`: [#387](haskell/vector#387)
* Remove `CPP` driven error reporting in favor of `HasCallStack`:
[#397](haskell/vector#397)
* Remove redundant `Storable` constraints on to/from `ForeignPtr` conversions:
[#394](haskell/vector#394)
* Add `unsafeCast` to `Primitive` vectors: [#401](haskell/vector#401)
* Make `(!?)` operator strict: [#402](haskell/vector#402)
* Add `readMaybe`: [#425](haskell/vector#425)
* Add `groupBy` and `group` for `Data.Vector.Generic` and the specialized
version in `Data.Vector`, `Data.Vector.Unboxed`, `Data.Vector.Storable` and
`Data.Vector.Primitive`. [#427](haskell/vector#427)
* Add `toArraySlice` and `unsafeFromArraySlice` functions for conversion to and
from the underlying boxed `Array`: [#434](haskell/vector#434)
This PR does the world a favor by reducing CPP usage in vector. 😄
The idea behind this PR is that all
Boundschecks get theHasCallStackconstraint, so they can propagate to the user's callsite, whileInternalandUnsafedo not, nevertheless the error message will still contain the module name and line number as before with CPP approach, because of the ghc's callstack innovation.For ghc-7.10 it will fall back to
call-stackpackage, which is a small price to pay for backwards compatibility with such and old ghc version.Next step will be to adding
HasCallStackto all other partial functions transitively, such PR in itself will supersede #184