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build: enable loading builtin modules at runtime #36215
Description
Is your feature request related to a problem? Please describe.
It might be a problem to build node entirely every time the path to the node builtin modules is changed.
Describe the solution you'd like
- During the configuration stage, instead of using
--node-builtin-modules-pathwith a path value, we can use an--enable-runtime-node-builtin-modulesflag to enable this feature. - At runtime, the path to the builtin modules can be read in from an environment variable
NODE_BUILTIN_MODULES_PATHusinglibuvOR it can be passed to node as a command line argument using--node-builtin-modules-pathwith a path value.
Fixes: nodejs/help#3087
Ref: #31321
Activity
richardlau commentedon Nov 21, 2020
I’m very hesitant to make this a runtime option. It’s fine as a build time option for development of Node.js core but opens up potential attack vectors to replace the built-in modules. The work towards more use of primordials in the built-in modules suggests we are moving away from allowing the built-ins from being changed at runtime.
devsnek commentedon Nov 21, 2020
-1 on this. I made the configure option as dumb as possible so people don't get ideas about using it outside of quick development changes to node's builtin js files.
RaisinTen commentedon Nov 21, 2020
This is only for quick development changes to node's builtin js files. What's wrong with having this as a runtime option? How do you attack something which is not even compiled because it has been excluded because of guarding
ifdefs?devsnek commentedon Nov 21, 2020
I don't understand what the point of this is. What functionality is
--node-builtin-modules-path=$(cwd)missing?RaisinTen commentedon Nov 22, 2020
It's hard to change the location frequently. Reading the discussion in the PR, it felt as if this was intended to be made into a runtime feature but it didn't happen because you weren't sure about how to fetch the data from the options parser. I don't quite see what prevents us from making this flexible given that people won't be using it outside of development anyway.
devsnek commentedon Nov 22, 2020
Why does the location need to change? I'm curious about the use case which is driving this issue.
RaisinTen commentedon Nov 22, 2020
The location changes if:
devsnek commentedon Nov 22, 2020
if you have separate node checkouts imo you should just build node once in each checkout.
RaisinTen commentedon Nov 22, 2020
That takes more time. Instead if we just keep the other repos updated and build/rebuild node in one, it's way faster to develop.
mmomtchev commentedon Nov 24, 2020
By the way, there is support for that option coming in the November edition of the JS debugger
microsoft/vscode-js-debug@737f6c0
The vscode-js-debug has been rather nice, because this is a specific feature for Node developers
RaisinTen commentedon Nov 24, 2020
That's very cool! I don't use vscode unfortunately. :/
Melab commentedon Oct 24, 2021
This should happen. It should also be such that files can be added and removed from the set of builtin modules.
Melab commentedon Oct 24, 2021
But that takes much time. I've had faster build times with the Linux kernel than with V8 (which is just a small part of Node) and changing small amounts of code that could be modular for testing and development purposes makes development take orders of magnitude longer.
RaisinTen commentedon Mar 26, 2022
I was using a slow setup (a very old 32-bit HP Pavilion running Ubuntu 18) when I posted this issue. This is not a problem for me anymore now that I'm on an M1 MBP, closing.