cleanup: reduce the number of `#include "env.h"` and `#include "env-inl.h"` in the code base #27531

joyeecheung · 2019-05-02T11:38:41Z

Because of how Environment is used in the code base (e.g. to grab Node.js things from callbacks, to have fast access to persistent properties), Environment is used in almost every C++ file, which results in a lot of #include "env.h" and #include "env-inl.h" in the code base. However many files (mostly headers) only need a forward declaration of class Environment instead of requiring env.h or env-inl.h because they just need to know the Environment type to have Environment* in the declarations. When there is code in a header that actually uses something from Environment (so a forward declaration is not enough), the code may be moved out of the header if it is not in a hot path (i.e. it does not need to be inlined).

Reducing the number of these includes should reduce the amount of files being compiled whenever env.h/env-inl.h is touched.

The text was updated successfully, but these errors were encountered:

joyeecheung · 2019-05-02T11:39:32Z

I think this is a good first issue if you know how forward declaration and C++ headers work. If nobody picks this up (say in a week) I'll do it anyway because...I touch env.h too much these days and want to spend less time waiting for recompilation ;)

refack · 2019-05-02T12:18:44Z

if it is not in a hot path (i.e. it does not need to be inlined).

BTW I believe that as of C++11 this assumption is not as relevant as it used to be.
Language-wise inline has come to mean "may have multiple definitions" on the one hand, and compilers are now inlining anything and do LTO if they think it will improve performance, on the other hand.

Jinshuo1994 · 2019-05-04T17:45:04Z

I think the instructions from @joyeecheung are very clear. Can I take up this issue? Thanks!

joyeecheung · 2019-05-05T03:34:13Z

@Jinshuo1994 sure, go head!

BeniCheni · 2019-05-09T05:47:03Z

Since I'm learning c++ in context of Node core, I tried out #27620 for this "good first issue" for c++ in core. Thanks.

sarkararpan710 · 2019-05-18T11:05:37Z

Hi, This is my first time with contributing to open source and would like to know, how exactly I can help.
Is this issue still open? Any build instructions that might help me understand how I can contribute.
Thanks.

joyeecheung · 2019-05-20T10:20:22Z

@sarkararpan710 There was #27620 but it did not exactly do what this issue requests. Since there has been no progress there since more than a week, I think you can take another stab at this - please take a look at #27620 (comment) about what the request is.

BeniCheni · 2019-05-20T12:07:08Z

@joyeecheung, sorry about the delay to update the PR. Been busy w. work lately. I’ll close the PR, and look out for other opportunities to do PRs.

carolinedarling · 2019-05-22T18:57:10Z

@joyeecheung I was wondering if I could work on this issue, is it still something that needs to be worked on? I am brand new to open-source and this would be my first contribution, so please excuse if I ask something ignorant.

sam-github · 2019-05-22T19:32:40Z

I suggest waiting until #27755 lands. It probably (mostly) cleans up many unnecessary includes of env-inl.h, but it doesn't deal with the problem of files that include env.h purely for its class declaration.

As a heads up, to do this, you'll need to know how a class Environment; forward-declaration can be used to replace some instance of #include "env.h".

carolinedarling · 2019-05-22T19:57:59Z

@sam-github Thank you very much. Will this take about 48 hours? How will I know when it lands? I appreciate your comment.

sam-github · 2019-05-22T20:15:17Z

Hopefully will land by the end of day. You can probably use the 'subscribe' button on the PR to start getting updates on it.

carolinedarling · 2019-05-22T21:16:15Z

@sam-github Are we waiting for someone with write access to merge it with Master, am I understanding? Then, I re-build and start working? Thank you. Thank you for your patience with a new person, I am in my last quarter of a CS degree and new to git.

alferpal · 2019-10-23T09:26:11Z

Does this issue still need attention? I would like to try and fix it

joyeecheung · 2019-10-24T15:50:11Z

@alferpal I think this still is an issue, but maybe to a smaller extent.

BTW https://include-what-you-use.org/ can probably be useful in hunting these down but I have never tried to get it working in this code base.

alferpal · 2019-10-24T17:31:54Z

Thank you for the tip, @joyeecheung .

I'll try what you suggested.

alferpal · 2019-10-26T15:28:29Z

I've tried to do a first pass of the cleanup in the header files, when possible.

My intention is to make another more thorough pass using the tool @joyeecheung mentioned, but that will take a bit more time as I have to get familiar with it and so on.

Submitted the PR because I think a little improvement is always welcome, and I don't know when I'll find the time to sit and get more familiar with the codebase.

Due to how the Environment class is used through the codebase, there are a lot of includes referencing either env.h or env-inl.h. This can cause that when any development touches those libraries, a lot of files have to be recompiled. This commit attempts to change those includes by forward declarations when possible to mitigate the issue. Refs: #27531 PR-URL: #30133 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Joyee Cheung <[email protected]> Reviewed-By: David Carlier <[email protected]> Reviewed-By: Franziska Hinkelmann <[email protected]>

Due to how the Environment class is used through the codebase, there are a lot of includes referencing either env.h or env-inl.h. This can cause that when any development touches those libraries, a lot of files have to be recompiled. This commit attempts to change those includes by forward declarations when possible to mitigate the issue. Refs: nodejs/node#27531 PR-URL: nodejs/node#30133 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Joyee Cheung <[email protected]> Reviewed-By: David Carlier <[email protected]> Reviewed-By: Franziska Hinkelmann <[email protected]>

Due to how the Environment class is used through the codebase, there are a lot of includes referencing either env.h or env-inl.h. This can cause that when any development touches those libraries, a lot of files have to be recompiled. This commit attempts to change those includes by forward declarations when possible to mitigate the issue. Refs: #27531 PR-URL: #30133 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Joyee Cheung <[email protected]> Reviewed-By: David Carlier <[email protected]> Reviewed-By: Franziska Hinkelmann <[email protected]>

alferpal · 2019-11-07T19:52:28Z

I've managed to clean some more headers leftover in the code using include-what-you-use.

For those that haven't used it, it builds the project and outputs a list of suggestions for headers that should be added or removed and the total list of includes and forward declarations a file should have.

The output is something like this:

../src/api/hooks.cc should add these lines:
#include "env.h"             // for Environment
#include "node.h"            // for async_context, async_id, AtExit, EmitAsy...
#include "util.h"            // for CHECK_NOT_NULL, FIXED_ONE_BYTE_STRING
#include "v8.h"              // for Local, String, Integer, Isolate (ptr only)

../src/api/hooks.cc should remove these lines:

The full include-list for ../src/api/hooks.cc:
#include "async_wrap.h"      // for AsyncWrap
#include "env-inl.h"         // for Environment::GetCurrent, Environment::co...
#include "env.h"             // for Environment
#include "node.h"            // for async_context, async_id, AtExit, EmitAsy...
#include "node_internals.h"  // for DebugSealHandleScope
#include "node_process.h"    // for ProcessEmit
#include "util.h"            // for CHECK_NOT_NULL, FIXED_ONE_BYTE_STRING
#include "v8.h"              // for Local, String, Integer, Isolate (ptr only)

The instructions on IWYU's documentation don't manage to build node, as make will exit just after finishing building v8 due to all the suggestions thrown from IWYU.

I managed to get a full build using the following:

make -i -k -j8 CXX=/usr/bin/include-what-you-use 2>iwyu.log
IWYU outputs it's suggestions on stderr, so that's why the redirection

Leaving this hoping it helps.

Due to how the Environment class is used through the codebase, there are a lot of includes referencing either env.h or env-inl.h. This can cause that when any development touches those libraries, a lot of files have to be recompiled. This commit attempts to change those includes by forward declarations when possible to mitigate the issue. Refs: #27531 PR-URL: #30133 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: Joyee Cheung <[email protected]> Reviewed-By: David Carlier <[email protected]> Reviewed-By: Franziska Hinkelmann <[email protected]>

Node codebase has evolved a lot in the more than 10 years of its existence. As more features (and code) have been added, changed, removed, it's sometimes hard to keep track of what gets used and what not. This commits attempts to clean some of those potentially left-over headers using suggestions from include-what-you-use Refs: #27531 PR-URL: #30328 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: Joyee Cheung <[email protected]> Reviewed-By: James M Snell <[email protected]>

Due to how the Environment class is used throughout the codebase, there are a log of includes referencing eitehr env.h or env-inl.h. This commit cleans up the remaining extra includes of 'env.h' or 'env-inl.h' and adds forward declarations of the Environment class. PR-URL: nodejs#32293 Refs: nodejs#27531

Due to how the Environment class is used throughout the codebase, there are a log of includes referencing eitehr env.h or env-inl.h. This commit cleans up the remaining extra includes of 'env.h' or 'env-inl.h' and adds forward declarations of the Environment class. PR-URL: #32293 Refs: #27531 Fixes: #27531 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: James M Snell <[email protected]>

Due to how the Environment class is used throughout the codebase, there are a log of includes referencing eitehr env.h or env-inl.h. This commit cleans up the remaining extra includes of 'env.h' or 'env-inl.h' and adds forward declarations of the Environment class. PR-URL: nodejs#32293 Refs: nodejs#27531 Fixes: nodejs#27531 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: James M Snell <[email protected]>

Due to how the Environment class is used throughout the codebase, there are a log of includes referencing eitehr env.h or env-inl.h. This commit cleans up the remaining extra includes of 'env.h' or 'env-inl.h' and adds forward declarations of the Environment class. PR-URL: #32293 Refs: #27531 Fixes: #27531 Reviewed-By: Anna Henningsen <[email protected]> Reviewed-By: James M Snell <[email protected]>

joyeecheung added c++ Issues and PRs that require attention from people who are familiar with C++. good first issue Issues that are suitable for first-time contributors. labels May 2, 2019

BeniCheni mentioned this issue May 9, 2019

src: reduce env.h & env-inl.h include lines #27620

Closed

3 tasks

sam-github mentioned this issue May 10, 2019

src: remove util-inl.h from header files #27631

Closed

4 tasks

trivikr added the Hacktoberfest label Oct 1, 2019

aug2uag mentioned this issue Oct 14, 2019

Multiple #import "env.h" in src/node_stat_watcher #29975

Closed

alferpal mentioned this issue Oct 26, 2019

src: change env.h includes for forward declarations when possible #30133

Closed

2 tasks

Trott removed the Hacktoberfest label Nov 3, 2019

alferpal mentioned this issue Nov 7, 2019

src: cleanup unused headers #30328

Closed

2 tasks

nkreeger mentioned this issue Mar 16, 2020

src: Fix extra includes of "env.h" and "env-inl.h" in this directory. #32293

Closed

addaleax closed this as completed in 12a2997 Apr 2, 2020

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cleanup: reduce the number of `#include "env.h"` and `#include "env-inl.h"` in the code base #27531

cleanup: reduce the number of `#include "env.h"` and `#include "env-inl.h"` in the code base #27531

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cleanup: reduce the number of #include "env.h" and #include "env-inl.h" in the code base #27531

cleanup: reduce the number of #include "env.h" and #include "env-inl.h" in the code base #27531

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cleanup: reduce the number of `#include "env.h"` and `#include "env-inl.h"` in the code base #27531

cleanup: reduce the number of `#include "env.h"` and `#include "env-inl.h"` in the code base #27531

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