Library environment broken (?) in formula test phase, in CI only

[lelegard]

Output of brew config

N/A

Output of brew doctor

N/A

Description of issue

Hi,

What are the specific characteristics of the running environment in the formula test phase during CI tests, following a pull request in homebrew-core?

Here is the situation I have. I fixed an existing formula for libtomcrypt. This is not a new version. This is a fix of an existing formula that I didn't author. In short, libtomcrypt was unable to perform asymmetric cryptography in Homebrew because of a missing dependency on libtommath (and a few missing symbols in the make command).

I fixed it on my macOS13 arm64 system. I fixed the formula, reinstalled --from-source using the locally fixed formula. It works:

• brew test libtomcrypt passes. It basically runs the test program which was build during the installation phase.
• Applications work and asymmetric cryptography algorithms are now available.

So far, so good, I submitted a pull request for the fixed formula.

Here comes the problem: the test phase of the macOS11-arm64 fails in the CI (and tests on other platforms were cancelled). The same brew test libtomcrypt (which passes on my system) fails in the CI with this error:

==> Testing libtomcrypt
==> ./test
dyld: Library not loaded: @loader_path/../../../../../opt/libtommath/lib/libtommath.1.dylib
    Referenced from: /private/tmp/libtomcrypt-test-20230824-29211-1af4hzi/./test
    Reason: image not found

The library libtommath.1.dylib is not found. This library is provided by libtommath (note: "math", not "crypt"), the new dependency I added in the formula.

Note that the build of libtomcrypt succeeded. Since the build uses libtommath, the library was there at the time of the build.

However, the very same library is no longer found in the test phase.

I am a bit surprised by the referenced path @loader_path/../../../../../opt/libtommath/lib. It this expected? This path is obviously the reason for the error.

The same test command works on my system.

Additional information:

• For some reason, the test program is built during the build phase and installed as share/libtomcrypt/test. This executable tests all supported cryptographic algorithms and can be run at any time after installation. Why? No idea.
• The test program only depends on the libtommath library, the dependency I added. Before the fix, this dependency was not present, which explains why it worked.

$ otool -L test
test:
	/opt/homebrew/opt/libtommath/lib/libtommath.1.dylib (compatibility version 4.0.0, current version 4.0.0)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1319.100.3)

• The referenced path is hardcoded during the build. On my system:

$ otool -l test
...
Load command 14
          cmd LC_LOAD_DYLIB
      cmdsize 80
         name /opt/homebrew/opt/libtommath/lib/libtommath.1.dylib (offset 24)
   time stamp 2 Thu Jan  1 01:00:02 1970
      current version 4.0.0
compatibility version 4.0.0
...

What should I update in the formula to make sure that the test application correctly runs in the CI?

[ZhongRuoyu]

Thanks for the pull request. Please see review at Homebrew/homebrew-core#140370 (review).