使用OASIS编译项目时OCamlfind无法找到本地包的技术求助

Let's walk through solving your problem with the local why3 package not being found by OCamlfind, and address that META file warning along the way.

First: Understand the Root Issues #

1. OCamlfind can't locate why3: This happens because either your OCAMLPATH isn't pointing to the right directory, or the why3 META file (which OCamlfind uses to locate packages) is incomplete.
2. META file warning: The directory directive is missing from the META file/template, which tells OCamlfind where the compiled library files live.

Step 1: Fix the why3 META File #

When you built why3 locally with --enable-local, the generated META file might be missing critical info. Let's fix that:

1. Navigate to your why3-0.88.3 source directory.
2. Look for a META file (not META.in, which is a template). If it doesn't exist, run:

   make META
   

3. Open the META file in a text editor. Add or update the directory line to point to where the compiled why3 libraries are stored (usually lib/why3 relative to the source root):

   directory = "lib/why3"
   

Step 2: Set OCAMLPATH Correctly #

OCAMLPATH tells OCamlfind where to look for local packages. You need to point it to the directory containing the fixed META file:

1. Run this command (replace ~/why3-0.88.3 with your actual why3 source path):

   export OCAMLPATH="$OCAMLPATH:~/why3-0.88.3/lib/why3/"
   

2. Verify it works by running:

   ocamlfind query why3
   

   This should return the path to your local why3 library directory. If it does, you're good to go!

Pro tip: To make this permanent, add the export OCAMLPATH line to your shell profile (e.g., ~/.bashrc or ~/.zshrc).

Step 3: Re-Run OASIS Setup #

Now that OCamlfind can locate why3, re-run your OASIS commands in your project directory:

oasis setup
./configure

OCamlfind should no longer throw the "Package 'why3' not found" error.

Alternative: Register the Package with OCamlfind #

If setting OCAMLPATH doesn't work, you can directly register the local why3 package with OCamlfind:

ocamlfind add why3 ~/why3-0.88.3/lib/why3/

This adds a permanent entry to OCamlfind's configuration, so you won't need to mess with OCAMLPATH for this package.

Why Did the META.in Warning Happen? #

That warning popped up because you pointed OCAMLPATH to the directory containing META.in (the unprocessed template file) instead of the generated META file. OCamlfind tries to parse any file starting with META, and META.in lacks the directory directive (which is usually filled in during the configure step).

Content of the question来源于stack exchange，提问作者Lhooq