build: look for libnode.so in lib subdirectory

[khardix]

When building with --shared, ninja will output the libnode.so into a {build_dir}/lib directory, not in the root {build_dir}. This fixes the install script to look for it in the correct place.

---

Found during review of a Fedora rpm, where we apparently been moving the libnode.so manually to the root of the build directory manually this entire time. Let's see if we can stop doing that. 😅

[khardix]

CC @richardlau FYI

[richardlau]

@khardix Unfortunately the make and ninja generators in gyp use different output directories, and this breaks non-ninja builds.
e.g.

$ tools/install.py --dest-dir /tmp/testinstl --prefix "" install
installing /tmp/testinstl/bin/node
installing /tmp/testinstl/lib/libnode.so.137
Traceback (most recent call last):
  File "/home/rlau/sandbox/github/node/tools/install.py", line 426, in <module>
    run(parse_options(sys.argv[1:]))
  File "/home/rlau/sandbox/github/node/tools/install.py", line 379, in run
    files(options, install)
  File "/home/rlau/sandbox/github/node/tools/install.py", line 185, in files
    action(options, [os.path.join(options.build_dir, 'lib', output_lib)],
  File "/home/rlau/sandbox/github/node/tools/install.py", line 84, in install
    try_copy(options, path, dest)
  File "/home/rlau/sandbox/github/node/tools/install.py", line 73, in try_copy
    return shutil.copy2(source_path, target_path)
  File "/usr/lib64/python3.9/shutil.py", line 444, in copy2
    copyfile(src, dst, follow_symlinks=follow_symlinks)
  File "/usr/lib64/python3.9/shutil.py", line 264, in copyfile
    with open(src, 'rb') as fsrc:
FileNotFoundError: [Errno 2] No such file or directory: '/home/rlau/sandbox/github/node/out/Release/lib/libnode.so.137'

Using make instead of ninja and configure --shared, I end up with:

$ find . -type f -name "libnode.so.*"
./out/Release/obj.target/libnode.so.137
./out/Release/.deps/home/rlau/sandbox/github/node/out/Release/obj.target/libnode.so.137.d
./out/Release/.deps/home/rlau/sandbox/github/node/out/Release/libnode.so.137.d
./out/Release/libnode.so.137
$

I'm not sure if there's an easy way for install.py to know whether ninja was used. If configure is passed --ninja then I believe the generated config.mk will contain

BUILD_WITH=ninja

(BUILD_WITH will not be present there at all if --ninja is NOT passed to configure).

[khardix]

Thanks for the analysis; I'll try to take another look at this next week (we have holidays in Czechia this one).

[richardlau]

Requesting changes as per #58213 (comment) (since this now has an approval).

[khardix]

I tried to look into various places whether the ninja and/or the make generator could be persuaded to output files to the same places as the other one, but did not find anything. Granted, I'm not versed in using these tools too much, so it's entirely possible I missed something obvious.

I whipped the new commit as an alternative – the tools/install.py will now try to look at both possible places and install the first libnode.so that actually exist. It's a bit of a brute force approach with it's own drawbacks, but it should (mostly) work for both generators and not require significant changes anywhere else. 🤷 Let me know what you think about it.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/66980/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/66982/

[nodejs-github-bot]

Landed in cb88e99