Re: [MirageOS-devel] inconsistent assumptions over interface error

[Anil Madhavapeddy <anil@xxxxxxxxxx>]

Hi Gregory, [ccing mirageos-devel]

The root cause of this issue is a clash with top-level module names.  Somewhere in your library dependency chain, something has also defined a module called "Base64" that is different from the one that Nocrypto thinks its using.

One way to fix this is by not exposing a library's internal modules to the outside world by packing them inside a single top-level module.  Cohttp is one example of a library that does this.  (see https://realworldocaml.org/v1/en/html/the-compiler-frontend-parsing-and-type-checking.html#modules-and-separate-compilation for more information on packing).

It's difficult to workaround this without just fixing the libraries themselves -- although you will never get a segfault (as would happen in C if you mix up object files), the compiler will just reject inconsistent library checksums all the time.

I'm not sure which makefile you're referring to (vs oasis below), but perhaps David and Hannes can comment on whether they can pack the various crypto libraries for easier use.

Also, we could just pull Base64 into a separate OPAM package since it's very commonly cut-and-pasted.  I've taken a quick shot at this on https://github.com/mirage/ocaml-base64.  This is a different implementation (but possibly the same spec) as nocrypto's, so needs some review to see if they're compatible or not (padding is possibly slightly different).

-anil

On 2 Aug 2014, at 13:08, Gregory Tsipenyuk <gt303@xxxxxxxxx> wrote:

Hi Anil,

I got another “inconsistent assumptions” issue. It looks like it is similar to the one I opened a few days ago against asn1-combinators. Nocrypto does have its own Base64 module. What puzzles me though is that  it fails if I build with oasis generated stuff and if I build with the regular Makefile then it builds. Can you think of any flags that I can tweak to fix it?

Thanks,

Gregory 

File "_none_", line 1:

Error: Files utils.cmx

       and /Users/gregt/.opam/4.01.0+clang-fix/lib/nocrypto/nocrypto.cmxa

       make inconsistent assumptions over interface Base64

Command exited with code 2

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