llvm dev - Dec 2019 - [RFC] High-Level Code-Review Documentation Update

+1 in general, and Philip has good suggestions as well!

-- 
Mehdi


On Sat, Nov 16, 2019 at 8:37 AM Philip Reames via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> + 1 in general, a couple of suggestions
>
> On 11/14/19 7:46 PM, Finkel, Hal J. via llvm-dev wrote:
> > Hi, everyone,
> >
> > I've been fielding an increasing number of questions about how our
> > code-review process in LLVM works from people who are new to our
> > community, and it's been pointed out to me that our documentation
on
> > code reviews is both out of date and not as helpful as it could be to
> > new developers.
> >
> >    http://llvm.org/docs/DeveloperPolicy.html#code-reviews
> >
> > I would like to compose a patch to update this, but before I do that,
I
> > want to highlight some of my thoughts to get feedback. My intent is to
> > capture our community best practices in writing so that people new to
> > our community understand our processes and expectations. Here are some
> > things that I would like to capture:
> >
> >   1. You do not need to be an expert in some area of the compiler to
> > review patches; it's fine to ask questions about what some piece
of code
> > is doing. If it's not clear to you what is going on, you're
unlikely to
> > be the only one. Extra comments and/or test cases can often help (and
> > asking for comments in the test cases is fine as well).
> Authors are encouraged to interpret questions as reasons to reexamine
> the readability of the code in question.  Structural changes, or further
> comments may be appropriate.
> >
> >   2. If you review a patch, but don't intend for the review
process to
> > block on your approval, please state that explicitly. Out of courtesy,
> > we generally wait on committing a patch until all reviewers are
> > satisfied, and if you don't intend to look at the patch again in a
> > timely fashion, please communicate that fact in the review.
> >
> >   3. All comments by reviewers should be addressed by the patch
author.
> > It is generally expected that suggested changes will be incorporated
> > into the next revision of the patch unless the author and/or other
> > reviewers can articulate a good reason to do otherwise (and then the
> > reviewers must agree). If you suggest changes in a code review, but
> > don't wish the suggestion to be interpreted this strongly, please
state
> > so explicitly.
> >
> >   4. Reviewers may request certain aspects of a patch to be broken out
> > into separate patches for independent review, and also, reviewers may
> > accept a patch conditioned on the author providing a follow-up patch
> > addressing some particular issue or concern (although no committed
patch
> > should leave the project in a broken state). Reviewers can also accept
a
> > patch conditioned on the author applying some set of minor updates
prior
> > to committing, and when applicable, it is polite for reviewers to do
so.
> >
> >   5. Aim to limit the number of iterations in the review process. For
> > example, when suggesting a change, if you want the author to make a
> > similar set of changes at other places in the code, please explain the
> > requested set of changes so that the author can make all of the
changes
> > at once. If a patch will require multiple steps prior to approval
(e.g.,
> > splitting, refactoring, posting data from specific performance tests),
> > please explain as many of these up front as possible. This allows the
> > patch author to make the most-efficient use of his or her time.
> If the path forward is not clear - because the patch is too large to
> meaningful review, or direction needs to be settled - it is fine to
> suggest a clear next step (e.g. landing a refactoring) followed by a
> re-review.  Please state explicitly if the path forward is unclear to
> prevent confusions on the part of the author.
> >
> >   6. Some changes are too large for just a code review. Changes that
> > should change the Language Reference (e.g., adding new
> > target-independent intrinsics), adding language extensions in Clang,
and
> > so on, require an RFC on *-dev first. For changes that promise
> > significant impact on users and/or downstream code bases, reviewers
can
> > request an RFC (Request for Comment) achieving consensus before
> > proceeding with code review. That having been said, posting initial
> > patches can help with discussions on an RFC.
> >
> > Lastly, the current text reads, "Code reviews are conducted by
email on
> > the relevant project’s commit mailing list, or alternatively on the
> > project’s development list or bug tracker.", and then only later
> > mentions Phabricator. I'd like to move Phabricator to be mentioned
on
> > this line before the other methods.
> >
> > Please let me know what you think.
> >
> > Thanks again,
> >
> > Hal
>
> A couple of additional things:
>
> Only a single LGTM is required.  Reviewers are expected to only LGTM
> patches they're confident in their knowledge of.  Reviewers may review
> and provide suggestions, but explicitly defer LGTM to someone else.
> This is encouraged and a good way for new contributors to learn the code.
>
> There is a cultural expectation that at least one reviewer is from a
> different organization than the author of the patch.  If that's not
> possible, care should be taken to ensure overall direction has been
> widely accepted.
>
> Post commit review is encouraged via either phabricator or email.  There
> is a strong expectation that authors respond promptly to post commit
> feedback and address it.  Failure to do so is cause for the patch to be
> reverted.  If substantial problems are identified, it is expected that
> the patch is reverted, fixed offline, and then recommitted (possibly
> after further review.)
>
>
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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Thanks, everyone! I'll work on a patch soon incorporating the feedback on
this thread.

 -Hal

On 11/16/19 7:56 PM, Mehdi AMINI wrote:
+1 in general, and Philip has good suggestions as well!

--
Mehdi


On Sat, Nov 16, 2019 at 8:37 AM Philip Reames via llvm-dev <llvm-dev at
lists.llvm.org<mailto:llvm-dev at lists.llvm.org>> wrote:
+ 1 in general, a couple of suggestions

On 11/14/19 7:46 PM, Finkel, Hal J. via llvm-dev wrote:
> Hi, everyone,
>
> I've been fielding an increasing number of questions about how our
> code-review process in LLVM works from people who are new to our
> community, and it's been pointed out to me that our documentation on
> code reviews is both out of date and not as helpful as it could be to
> new developers.
>
>    http://llvm.org/docs/DeveloperPolicy.html#code-reviews
>
> I would like to compose a patch to update this, but before I do that, I
> want to highlight some of my thoughts to get feedback. My intent is to
> capture our community best practices in writing so that people new to
> our community understand our processes and expectations. Here are some
> things that I would like to capture:
>
>   1. You do not need to be an expert in some area of the compiler to
> review patches; it's fine to ask questions about what some piece of
code
> is doing. If it's not clear to you what is going on, you're
unlikely to
> be the only one. Extra comments and/or test cases can often help (and
> asking for comments in the test cases is fine as well).
Authors are encouraged to interpret questions as reasons to reexamine
the readability of the code in question.  Structural changes, or further
comments may be appropriate.
>
>   2. If you review a patch, but don't intend for the review process to
> block on your approval, please state that explicitly. Out of courtesy,
> we generally wait on committing a patch until all reviewers are
> satisfied, and if you don't intend to look at the patch again in a
> timely fashion, please communicate that fact in the review.
>
>   3. All comments by reviewers should be addressed by the patch author.
> It is generally expected that suggested changes will be incorporated
> into the next revision of the patch unless the author and/or other
> reviewers can articulate a good reason to do otherwise (and then the
> reviewers must agree). If you suggest changes in a code review, but
> don't wish the suggestion to be interpreted this strongly, please state
> so explicitly.
>
>   4. Reviewers may request certain aspects of a patch to be broken out
> into separate patches for independent review, and also, reviewers may
> accept a patch conditioned on the author providing a follow-up patch
> addressing some particular issue or concern (although no committed patch
> should leave the project in a broken state). Reviewers can also accept a
> patch conditioned on the author applying some set of minor updates prior
> to committing, and when applicable, it is polite for reviewers to do so.
>
>   5. Aim to limit the number of iterations in the review process. For
> example, when suggesting a change, if you want the author to make a
> similar set of changes at other places in the code, please explain the
> requested set of changes so that the author can make all of the changes
> at once. If a patch will require multiple steps prior to approval (e.g.,
> splitting, refactoring, posting data from specific performance tests),
> please explain as many of these up front as possible. This allows the
> patch author to make the most-efficient use of his or her time.
If the path forward is not clear - because the patch is too large to
meaningful review, or direction needs to be settled - it is fine to
suggest a clear next step (e.g. landing a refactoring) followed by a
re-review.  Please state explicitly if the path forward is unclear to
prevent confusions on the part of the author.
>
>   6. Some changes are too large for just a code review. Changes that
> should change the Language Reference (e.g., adding new
> target-independent intrinsics), adding language extensions in Clang, and
> so on, require an RFC on *-dev first. For changes that promise
> significant impact on users and/or downstream code bases, reviewers can
> request an RFC (Request for Comment) achieving consensus before
> proceeding with code review. That having been said, posting initial
> patches can help with discussions on an RFC.
>
> Lastly, the current text reads, "Code reviews are conducted by email
on
> the relevant project’s commit mailing list, or alternatively on the
> project’s development list or bug tracker.", and then only later
> mentions Phabricator. I'd like to move Phabricator to be mentioned on
> this line before the other methods.
>
> Please let me know what you think.
>
> Thanks again,
>
> Hal
A couple of additional things:

Only a single LGTM is required.  Reviewers are expected to only LGTM
patches they're confident in their knowledge of.  Reviewers may review
and provide suggestions, but explicitly defer LGTM to someone else.
This is encouraged and a good way for new contributors to learn the code.

There is a cultural expectation that at least one reviewer is from a
different organization than the author of the patch.  If that's not
possible, care should be taken to ensure overall direction has been
widely accepted.

Post commit review is encouraged via either phabricator or email.  There
is a strong expectation that authors respond promptly to post commit
feedback and address it.  Failure to do so is cause for the patch to be
reverted.  If substantial problems are identified, it is expected that
the patch is reverted, fixed offline, and then recommitted (possibly
after further review.)


_______________________________________________
LLVM Developers mailing list
llvm-dev at lists.llvm.org<mailto:llvm-dev at lists.llvm.org>
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory
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On Sat, Nov 16, 2019 at 5:56 PM Mehdi AMINI <joker.eph at gmail.com>
wrote:
> +1 in general, and Philip has good suggestions as well!
>
> --
> Mehdi
>
>
> On Sat, Nov 16, 2019 at 8:37 AM Philip Reames via llvm-dev <
> llvm-dev at lists.llvm.org> wrote:
>
>> + 1 in general, a couple of suggestions
>>
>> On 11/14/19 7:46 PM, Finkel, Hal J. via llvm-dev wrote:
>> > Hi, everyone,
>> >
>> > I've been fielding an increasing number of questions about how
our
>> > code-review process in LLVM works from people who are new to our
>> > community, and it's been pointed out to me that our
documentation on
>> > code reviews is both out of date and not as helpful as it could be
to
>> > new developers.
>> >
>> >    http://llvm.org/docs/DeveloperPolicy.html#code-reviews
>> >
>> > I would like to compose a patch to update this, but before I do
that, I
>> > want to highlight some of my thoughts to get feedback. My intent
is to
>> > capture our community best practices in writing so that people new
to
>> > our community understand our processes and expectations. Here are
some
>> > things that I would like to capture:
>> >
>> >   1. You do not need to be an expert in some area of the compiler
to
>> > review patches; it's fine to ask questions about what some
piece of
>> code
>> > is doing. If it's not clear to you what is going on,
you're unlikely to
>> > be the only one. Extra comments and/or test cases can often help
(and
>> > asking for comments in the test cases is fine as well).
>> Authors are encouraged to interpret questions as reasons to reexamine
>> the readability of the code in question.  Structural changes, or
further
>> comments may be appropriate.
>> >
>> >   2. If you review a patch, but don't intend for the review
process to
>> > block on your approval, please state that explicitly. Out of
courtesy,
>> > we generally wait on committing a patch until all reviewers are
>> > satisfied, and if you don't intend to look at the patch again
in a
>> > timely fashion, please communicate that fact in the review.
>> >
>> >   3. All comments by reviewers should be addressed by the patch
author.
>> > It is generally expected that suggested changes will be
incorporated
>> > into the next revision of the patch unless the author and/or other
>> > reviewers can articulate a good reason to do otherwise (and then
the
>> > reviewers must agree). If you suggest changes in a code review,
but
>> > don't wish the suggestion to be interpreted this strongly,
please state
>> > so explicitly.
>> >
>> >   4. Reviewers may request certain aspects of a patch to be broken
out
>> > into separate patches for independent review, and also, reviewers
may
>> > accept a patch conditioned on the author providing a follow-up
patch
>> > addressing some particular issue or concern (although no committed
>> patch
>> > should leave the project in a broken state). Reviewers can also
accept
>> a
>> > patch conditioned on the author applying some set of minor updates
>> prior
>> > to committing, and when applicable, it is polite for reviewers to
do so.
>> >
>> >   5. Aim to limit the number of iterations in the review process.
For
>> > example, when suggesting a change, if you want the author to make
a
>> > similar set of changes at other places in the code, please explain
the
>> > requested set of changes so that the author can make all of the
changes
>> > at once. If a patch will require multiple steps prior to approval
>> (e.g.,
>> > splitting, refactoring, posting data from specific performance
tests),
>> > please explain as many of these up front as possible. This allows
the
>> > patch author to make the most-efficient use of his or her time.
>> If the path forward is not clear - because the patch is too large to
>> meaningful review, or direction needs to be settled - it is fine to
>> suggest a clear next step (e.g. landing a refactoring) followed by a
>> re-review.  Please state explicitly if the path forward is unclear to
>> prevent confusions on the part of the author.
>> >
>> >   6. Some changes are too large for just a code review. Changes
that
>> > should change the Language Reference (e.g., adding new
>> > target-independent intrinsics), adding language extensions in
Clang,
>> and
>> > so on, require an RFC on *-dev first. For changes that promise
>> > significant impact on users and/or downstream code bases,
reviewers can
>> > request an RFC (Request for Comment) achieving consensus before
>> > proceeding with code review. That having been said, posting
initial
>> > patches can help with discussions on an RFC.
>> >
>> > Lastly, the current text reads, "Code reviews are conducted
by email on
>> > the relevant project’s commit mailing list, or alternatively on
the
>> > project’s development list or bug tracker.", and then only
later
>> > mentions Phabricator. I'd like to move Phabricator to be
mentioned on
>> > this line before the other methods.
>> >
>> > Please let me know what you think.
>> >
>> > Thanks again,
>> >
>> > Hal
>>
>> A couple of additional things:
>>
>> Only a single LGTM is required.  Reviewers are expected to only LGTM
>> patches they're confident in their knowledge of.  Reviewers may
review
>> and provide suggestions, but explicitly defer LGTM to someone else.
>> This is encouraged and a good way for new contributors to learn the
code.
>>
>> There is a cultural expectation that at least one reviewer is from a
>> different organization than the author of the patch.
>
>
Actually, while I'm OK with the other suggestions, I didn't pay
attention
to this one originally.
I'm very concerned about this: this looks like an assumption of bad faith
or malice in the review process, and I find this unhealthy if it were part
of the "cultural expectation". Moreover there are many areas of the
compiler where there aren't many people available to review changes.

I personally never really paid attention to who is the author/reviewer of a
patch from an organizational point of view, I haven't perceived this
culture of looking into affiliation so far. I never got the impression that
reviewer were more difficult with me than they would be with others.
There have been many patches that I reviewed that originated from other
people from the same company as mine (back when I was at Apple mostly). The
notion of "organization" is blurry: frequently this involved people
from
different teams inside the same company,  are they part of "the same
organization"? Some of these people I have never even ever met or never
heard of them before reviewing a patch (sometimes I don't even realize
since there is a Phabricator pseudo and not everyone is using their
business email here).

-- 
Mehdi




> If that's not
>> possible, care should be taken to ensure overall direction has been
>> widely accepted.
>>
>> Post commit review is encouraged via either phabricator or email. 
There
>> is a strong expectation that authors respond promptly to post commit
>> feedback and address it.  Failure to do so is cause for the patch to be
>> reverted.  If substantial problems are identified, it is expected that
>> the patch is reverted, fixed offline, and then recommitted (possibly
>> after further review.)
>>
>>
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>
>
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Yeah, +1 that people from the same organization are sometimes the only ones
working on a certain feature/area. (certainly I'd expect some discussion
about the feature in general to be discussed outside that group if it's in
any way contentious - but some stuff's clear enough (I think I implemented
debug_types years ago, likely with only Eric's approval, both of us being
at Google (probably many DWARF features were added/done this way, to be
honest - maybe some could've done witha  bit of broader discussion, but I
don't think either of us were "rubber stamping" the other's
work (if
anything I'm harder on my "friends" to be honest... :/ )))

On Wed, Nov 27, 2019 at 10:27 PM Mehdi AMINI via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
>
>
> On Sat, Nov 16, 2019 at 5:56 PM Mehdi AMINI <joker.eph at gmail.com>
wrote:
>
>> +1 in general, and Philip has good suggestions as well!
>>
>> --
>> Mehdi
>>
>>
>> On Sat, Nov 16, 2019 at 8:37 AM Philip Reames via llvm-dev <
>> llvm-dev at lists.llvm.org> wrote:
>>
>>> + 1 in general, a couple of suggestions
>>>
>>> On 11/14/19 7:46 PM, Finkel, Hal J. via llvm-dev wrote:
>>> > Hi, everyone,
>>> >
>>> > I've been fielding an increasing number of questions about
how our
>>> > code-review process in LLVM works from people who are new to
our
>>> > community, and it's been pointed out to me that our
documentation on
>>> > code reviews is both out of date and not as helpful as it
could be to
>>> > new developers.
>>> >
>>> >    http://llvm.org/docs/DeveloperPolicy.html#code-reviews
>>> >
>>> > I would like to compose a patch to update this, but before I
do that,
>>> I
>>> > want to highlight some of my thoughts to get feedback. My
intent is to
>>> > capture our community best practices in writing so that people
new to
>>> > our community understand our processes and expectations. Here
are some
>>> > things that I would like to capture:
>>> >
>>> >   1. You do not need to be an expert in some area of the
compiler to
>>> > review patches; it's fine to ask questions about what some
piece of
>>> code
>>> > is doing. If it's not clear to you what is going on,
you're unlikely
>>> to
>>> > be the only one. Extra comments and/or test cases can often
help (and
>>> > asking for comments in the test cases is fine as well).
>>> Authors are encouraged to interpret questions as reasons to
reexamine
>>> the readability of the code in question.  Structural changes, or
further
>>> comments may be appropriate.
>>> >
>>> >   2. If you review a patch, but don't intend for the
review process to
>>> > block on your approval, please state that explicitly. Out of
courtesy,
>>> > we generally wait on committing a patch until all reviewers
are
>>> > satisfied, and if you don't intend to look at the patch
again in a
>>> > timely fashion, please communicate that fact in the review.
>>> >
>>> >   3. All comments by reviewers should be addressed by the
patch
>>> author.
>>> > It is generally expected that suggested changes will be
incorporated
>>> > into the next revision of the patch unless the author and/or
other
>>> > reviewers can articulate a good reason to do otherwise (and
then the
>>> > reviewers must agree). If you suggest changes in a code
review, but
>>> > don't wish the suggestion to be interpreted this strongly,
please
>>> state
>>> > so explicitly.
>>> >
>>> >   4. Reviewers may request certain aspects of a patch to be
broken out
>>> > into separate patches for independent review, and also,
reviewers may
>>> > accept a patch conditioned on the author providing a follow-up
patch
>>> > addressing some particular issue or concern (although no
committed
>>> patch
>>> > should leave the project in a broken state). Reviewers can
also accept
>>> a
>>> > patch conditioned on the author applying some set of minor
updates
>>> prior
>>> > to committing, and when applicable, it is polite for reviewers
to do
>>> so.
>>> >
>>> >   5. Aim to limit the number of iterations in the review
process. For
>>> > example, when suggesting a change, if you want the author to
make a
>>> > similar set of changes at other places in the code, please
explain the
>>> > requested set of changes so that the author can make all of
the
>>> changes
>>> > at once. If a patch will require multiple steps prior to
approval
>>> (e.g.,
>>> > splitting, refactoring, posting data from specific performance
tests),
>>> > please explain as many of these up front as possible. This
allows the
>>> > patch author to make the most-efficient use of his or her
time.
>>> If the path forward is not clear - because the patch is too large
to
>>> meaningful review, or direction needs to be settled - it is fine to
>>> suggest a clear next step (e.g. landing a refactoring) followed by
a
>>> re-review.  Please state explicitly if the path forward is unclear
to
>>> prevent confusions on the part of the author.
>>> >
>>> >   6. Some changes are too large for just a code review.
Changes that
>>> > should change the Language Reference (e.g., adding new
>>> > target-independent intrinsics), adding language extensions in
Clang,
>>> and
>>> > so on, require an RFC on *-dev first. For changes that promise
>>> > significant impact on users and/or downstream code bases,
reviewers
>>> can
>>> > request an RFC (Request for Comment) achieving consensus
before
>>> > proceeding with code review. That having been said, posting
initial
>>> > patches can help with discussions on an RFC.
>>> >
>>> > Lastly, the current text reads, "Code reviews are
conducted by email
>>> on
>>> > the relevant project’s commit mailing list, or alternatively
on the
>>> > project’s development list or bug tracker.", and then
only later
>>> > mentions Phabricator. I'd like to move Phabricator to be
mentioned on
>>> > this line before the other methods.
>>> >
>>> > Please let me know what you think.
>>> >
>>> > Thanks again,
>>> >
>>> > Hal
>>>
>>> A couple of additional things:
>>>
>>> Only a single LGTM is required.  Reviewers are expected to only
LGTM
>>> patches they're confident in their knowledge of.  Reviewers may
review
>>> and provide suggestions, but explicitly defer LGTM to someone else.
>>> This is encouraged and a good way for new contributors to learn the
>>> code.
>>>
>>> There is a cultural expectation that at least one reviewer is from
a
>>> different organization than the author of the patch.
>>
>>
> Actually, while I'm OK with the other suggestions, I didn't pay
attention
> to this one originally.
> I'm very concerned about this: this looks like an assumption of bad
faith
> or malice in the review process, and I find this unhealthy if it were part
> of the "cultural expectation". Moreover there are many areas of
the
> compiler where there aren't many people available to review changes.
>
> I personally never really paid attention to who is the author/reviewer of
> a patch from an organizational point of view, I haven't perceived this
> culture of looking into affiliation so far. I never got the impression that
> reviewer were more difficult with me than they would be with others.
> There have been many patches that I reviewed that originated from other
> people from the same company as mine (back when I was at Apple mostly). The
> notion of "organization" is blurry: frequently this involved
people from
> different teams inside the same company,  are they part of "the same
> organization"? Some of these people I have never even ever met or
never
> heard of them before reviewing a patch (sometimes I don't even realize
> since there is a Phabricator pseudo and not everyone is using their
> business email here).
>
> --
> Mehdi
>
>
>
>
>
>> If that's not
>>> possible, care should be taken to ensure overall direction has been
>>> widely accepted.
>>>
>>> Post commit review is encouraged via either phabricator or email. 
There
>>> is a strong expectation that authors respond promptly to post
commit
>>> feedback and address it.  Failure to do so is cause for the patch
to be
>>> reverted.  If substantial problems are identified, it is expected
that
>>> the patch is reverted, fixed offline, and then recommitted
(possibly
>>> after further review.)
>>>
>>>
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>
>> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>
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