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src: start annotating native code side effect #21458

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TimothyGu
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Allows eager evaluation to take place for many builtin modules.

screenshot from 2018-06-22 01-37-13

Refs: #20977

/cc @nodejs/v8-inspector @benjamingr

Checklist
  • make -j4 test (UNIX), or vcbuild test (Windows) passes
  • commit message follows commit guidelines

@TimothyGu TimothyGu added c++ Issues and PRs that require attention from people who are familiar with C++. v8 engine Issues and PRs related to the V8 dependency. inspector Issues and PRs related to the V8 inspector protocol labels Jun 22, 2018
@nodejs-github-bot nodejs-github-bot added c++ Issues and PRs that require attention from people who are familiar with C++. lib / src Issues and PRs related to general changes in the lib or src directory. labels Jun 22, 2018
@TimothyGu
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NewFunctionTemplate(callback,
v8::Local<v8::Signature>(),
// TODO(TimothyGu): Investigate if SetMethod is ever
// used for constructors.
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That's easy to check, isn't it? Or do you suspect make test will miss instances?

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I'd rather leave that to a separate PR is what I meant.

env->SetMethod(target, "getHashes", GetHashes);
env->SetMethod(target, "getCurves", GetCurves);
env->SetMethod(target, "randomBytes", RandomBytes,
SideEffectType::kHasNoSideEffect);
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Is there a reason you annotated randomBytes but not pbkdf2 and scrypt? They all use the thread pool.

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Hmm, I didn't realize RandomBytes was async. I'll remove this part then.

Signature::New(env->isolate(), t));
Signature::New(env->isolate(), t),
// TODO(TimothyGu): should be deny
ConstructorBehavior::kAllow,
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Should be /* length */ 0, ConstructorBehavior::kAllow,. Likewise on line 3968.

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Oops, good catch. Fixed.

src/node.cc Outdated
env->SetMethod(process, "getgid", GetGid);
env->SetMethod(process, "getegid", GetEGid);
env->SetMethod(process, "getgroups", GetGroups);
env->SetMethod(process, "getuid", GetUid,
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Just a thought... but a env->SetSafeMethod(process, ...) variant that sets SideEfectType::kHasNoSideEffect automatically may be worthwhile.

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@bnoordhuis
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SetSafeMethod() is a bad name. Safe how? f you want something short, use SetMethodNSE() - a little cryptic but on point.

We could then later add SetMethodNSFW() for methods you wouldn't want to be seen calling at the office.

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jasnell commented Jun 23, 2018

I disagree on Safe being bad here... It's a fairly well known idea that "safe" methods have no side effects and NSE conveys no useful information. I think the code comments are enough to convey what Safe means here.

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It's a fairly well known idea that "safe" methods have no side effects

We have functions such as SafeGetenv() and SafeX509ExtPrint() where the Safe means they go the extra mile to stay secure. It doesn't denote anything about side effects.

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jasnell commented Jun 23, 2018

I'm not even remotely interested in debating it so whatever method name folks think is appropriate is fine with me. Having the utility method is what I wanted so I'm good with this.

@addaleax
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and NSE conveys no useful information

@TimothyGu I’d suggest just spelling it out then as NoSideEffect, if that’s alright with you? I agree with Ben that Safe is not a great name, it doesn’t convey much information either.

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@addaleax Sure, I'll fix that later.

@benjamingr
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For what it's worth Pure is typically used to indicate a function has no side effects - at least a lot more often than Safe or NSE. https://www.sitepoint.com/functional-programming-pure-functions/

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"Pure" suggests it's safe to collapse multiple calls because the return value depends only on the inputs. That clearly isn't true for functions such as process.uptime().

Compare gcc's __attribute__((pure)).

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Still looks good after rename

@TimothyGu
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@TimothyGu
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Landed in 65f6173.

@TimothyGu TimothyGu closed this Jun 26, 2018
@TimothyGu TimothyGu deleted the side-effects branch June 26, 2018 03:16
TimothyGu added a commit that referenced this pull request Jun 26, 2018
PR-URL: #21458
Refs: #20977
Reviewed-By: Anna Henningsen <[email protected]>
Reviewed-By: Gus Caplan <[email protected]>
Reviewed-By: Benjamin Gruenbaum <[email protected]>
Reviewed-By: Ben Noordhuis <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Joyee Cheung <[email protected]>
Reviewed-By: James M Snell <[email protected]>
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targos commented Jun 26, 2018

Depends on #21105 to land on v10.x

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