Any way to reload the built-in modules?

[RaisinTen]

Is there any way to reload the built-in modules into the node executable generated by make without recompiling the C++ part entirely?

[richardlau]

There's some functionality that was added in nodejs/node#31321. You will need to rebuild Node.js once with the --node-builtin-modules-path configure option to enable it.

[RaisinTen]

Thank you so much!

Which of these two should I execute at the top of the git repo of node:

• ./configure --node-builtin-modules-path=.
  

• ./configure --node-builtin-modules-path=lib
  

Both seem to produce the same output:

Node.js configure: Found Python 3.6.9...
Warning! Loading builtin modules from disk is for development
INFO: configure completed successfully

[richardlau]

It looks like between those two choices it would be the first as lib gets appended:
https://github.com/nodejs/node/blob/bb3cbba9533b37429292fd1005efb8099e7ba872/src/node_native_module.cc#L198

(FWIW I've never used this build feature before)

[RaisinTen]

Thank you for the help. I'll try using it. 🙂

[RaisinTen]

After building node with this mod I figured out that I should have used the absolute path to the node git repo instead. When using node from a different location, I get this error:

node/node[3415]: ../src/node_native_module.cc:215:v8::MaybeLocal<v8::String> node::native_module::NativeModuleLoader::LoadBuiltinModuleSource(v8::Isolate*, const char*): Assertion `(req.result) >= (0)' failed.

I was thinking about changing this functionality a bit. Instead of fixing the path in the configuration stage maybe we can enable this feature using a binary flag and during execution node will read in the builtin modules path from an environment variable.

[devsnek]

@RaisinTen if you give it an absolute path you won't have that issue.

[bl-ue]

@RaisinTen did you ever get it working? I tried running this:

./configure --debug --debug-node --gdb --v8-non-optimized-debug --v8-enable-object-print --debug-nghttp2 --node-builtin-modules-path=$PWD/lib --enable-asan --debug-lib

but the resulting node aborts, just like yours did.

❯ echo $PWD/lib
/Users/me/node/lib

[RaisinTen]

@bl-ue Yes, this works for me. :)
I think the value for --node-builtin-modules-path should be set to just $PATH without the /lib suffix because #3087 (comment).

[bl-ue]

Ohhh... I saw that message, but I didn't read it correctly. Makes perfect sense. Thank you 👍🏻