Apparently, I'm making inconsistent assumptions over an interface (dune, etc.)

Learning
1

So, I wrote this library called subprocess for working with OS processes. It’s a dune package. I installed it (or so I thought) with dune install.

I wrote a “script” for doing stuff with files (previewing them and then moving them to a folder). It’s called watchnmove. It is supposed to use the subprocess library. When I’m editing it, merlin seems to know the subprocess library and the interfaces it provides.

However, when I try to build watchnmove, I get the following error:

File "_none_", line 1:
Error: Files .watchnmove.eobjs/native/dune__exe__Watchnmove.cmx
       and /home/ninjaaron/.opam/4.10.0/lib/subprocess/subprocess.cmxa
       make inconsistent assumptions over interface Subprocess

Not really sure how to proceed at this point. dune build @check works fine (for the watchnmove script).

2

ocamlobjinfo is your friend. It can be that recorded (relative) path of source files is different. This will modify the hash and lead to this error

3

Thanks, but I don’t know how to act on this insight. Should I just read the man page for ocamlobjinfo? I don’t know what you’re advising me to do. This is my first time trying to use a library that I wrote and installed with dune. There are many things I do not know. e.g. how to change the recorded path.

4

ocamlobjinfo foo.cmi ocamlobjinfo whateever_uses_foo.cmi

check the hashes of Foo in the output

5

Are your projects someplace where others can clone/reproduce the problem?

6

I found the hash for my subprocess library, but there doesn’t appear to be any object file for the watchnmove program. This is the directory tree:

.
├── _build
│   ├── default
│   │   └── watchnmove.ml
│   └── log
├── dune
├── dune-project
├── foo
└── watchnmove.ml

2 directories, 6 files

I ran ocamlobjinfo on the cmxa file I was trying to use:

File /home/ninjaaron/.opam/4.10.0/lib/subprocess/subprocess.cmxa
Extra C object files:
Extra C options:
Name: Subprocess
CRC of implementation: d657ce8d0693089c410e832fc6ed51d0
Globals defined:
	Subprocess
Interfaces imported:
	618916e3750d258813c503390a6d11af	UnixLabels
	ba30fbe5ee87d3d4d5bd805af35f363b	Unix
	015289f70a832fcf8656f6e88b1a51e6	Subprocess
	c51d7a295527e9500ba69b459f81d6b3	Stdlib__uchar
	c5f4ef3f36de5f47b7041eed1deb9679	Stdlib__seq
	908ae2bf186b4ad7c88e5443c57d73af	Stdlib__printf
	d6c8b384cf8b1a3066eeb6d66bd95790	Stdlib__option
	13989ef6fbcb7235b257d3df9a80253a	Stdlib__list
	067e32179a81c1c8dbdd0a8d52b0c645	Stdlib__complex
	28161e4effde5ea372547815f87193ec	Stdlib__buffer
	33ee4c2e3aa5fb2f083dd780ce492c0b	Stdlib__bigarray
	9558001a029d7270458a252505f6a024	Stdlib__array
	aea3513d44d604b62eaff79ad12007b3	Stdlib
	f562e7b79dbe1bb1591060d6b4e854cf	CamlinternalFormatBasics
Implementations imported:
	27707ead31735f5fc007cca109489449	UnixLabels
	33e6bc48723c0388a908be1d5b5e43a2	Stdlib__seq
	19b790b69e71cc8a18d06eb2330f9df4	Stdlib__printf
	04b767392a141a521eea0ec7b68922c1	Stdlib__option
	e3a5f633b69d62d35929d9e3f6c26a20	Stdlib__list
	d8cbd5c6bb9dc377a421cad028946a12	Stdlib__array
	6b88613cf2b6620d6f11cd8a342880fc	Stdlib
Clambda approximation:
  _
Currying functions: 5 2 4
Apply functions:
Send functions:
Force link: no

I see a lot of hashes, and I don’t really know which ones I’m supposed to be looking at. I see one next to something that says CRC of implementation which is different from the one that says Subprocess under “Interfaces imported”.

Though I don’t think I’ve done everything you actually asked, let’s assume the hashes are mismatched. What would I do to correct that?

7

Ok, I also did this:

$ ocamlobjinfo /home/ninjaaron/.opam/4.10.0/lib/subprocess/subprocess.cmi 
File /home/ninjaaron/.opam/4.10.0/lib/subprocess/subprocess.cmi
Unit name: Subprocess
Interfaces imported:
	5f68cffdcdf0daa3a799416a60eb0ef4	Subprocess
	618916e3750d258813c503390a6d11af	UnixLabels
	ba30fbe5ee87d3d4d5bd805af35f363b	Unix
	c5f4ef3f36de5f47b7041eed1deb9679	Stdlib__seq
	067e32179a81c1c8dbdd0a8d52b0c645	Stdlib__complex
	33ee4c2e3aa5fb2f083dd780ce492c0b	Stdlib__bigarray
	aea3513d44d604b62eaff79ad12007b3	Stdlib
	f562e7b79dbe1bb1591060d6b4e854cf	CamlinternalFormatBasics
8

I found a solution:

Turns out I just had to recompile my subprocess library.

1 Like