

Show HN: GitCop – Automated Commit Message Validation for GitHub Pull Requests - Gazler
https://gitcop.com

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akoeplinger
Can the bot comment include an example of a good commit message?

Telling users that "Commits must be in the following format:
%{type}(%{scope}): %{description}" requires them to mentally parse and figure
out what this means. Giving an example along the lines of "perf(backend):
optimized db access" would make this easier.

~~~
Gazler
This is a great idea, definitely something worth implementing. Thanks for the
feedback.

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weavejester
It's a very nice idea, but the validation rules are extremely limited.

Perhaps I'm wrong, but all of the rule options on the site look like they
could have been implemented via regular expressions. Given the technical
expertise of your intended customers, why not allow them to set a list of
rules in the format: [regex, error-message], e.g.

    
    
        "^.{0,50}\n"         "The subject should be 50 characters or under"
        "^.+\n(.{0,72}\n)*$" "The body should have lines of 72 characters or under"
        "^\p{Upper}"         "The subject should be capitalized"

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Gazler
I think doing it like that is a neat idea. Perhaps there could be an
"advanced" page which is as you describe and the current method could be the
"simple" version?

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eLobato
This is quite cool, and actually something I'll propose to use at some
[http://github.com/theforeman](http://github.com/theforeman) repos.

I didn't really understood the format rules, so if the author posted this, a
help section would help. I try to enforce

    
    
        '%(type) #xxxx(: | -) %{description}'
    

How would you do that? #xxxx is just an issue number, so it can be #23891, and
after that I want a separator from the description, semi colon or hyphen are
fine. Probably %{scope} can be used but I didn't really understand it from the
inline help, sorry!

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Gazler
Hi, thanks for the feedback, it would be great to be used by a project like
Foreman!

Currently the string for the format only allows the 3 defined variables, type,
scope and description. I have been using this style at
[https://github.com/Gazler/changex/commits/master](https://github.com/Gazler/changex/commits/master)
to give you an idea of how it works.

I was concerned that the format string might be a little weird to get from the
help. I will try and clear this up a bit.

I have attempted to build the string that you requested, currently an or
separator is not supported, but I can take a look at adding it in.

Here are the format strings that I think match your use case. Using a colon as
a separator:

    
    
        test string: "Fixes #1234: foo"
        format:      "%{type} #%{scope}: %{description}"
        [type: "Fixes", scope: "1234", description: "foo"]
    

Using a hyphen as a separator:

    
    
        test string: "Fixes #1234 - foo"
        format:      "%{type} #%{scope} - %{description}"
        [type: "Fixes", scope: "1234", description: "foo"]
    

I hope this makes sense, let me know if you get it working!

~~~
eLobato
Interesting, that makes sense. I'll check if the rest of the team would be ok
with forcing commits to use colon as a separator until that feature is added.
:)

Still, what does %{scope} actually catch? Anything that's not %{type},
%{description} or an explicit character?

~~~
Gazler
Glad it made sense!

So the match is exact between the non %{..} characters. The idea for scope is
the context of the commit, in my libraries I use the name of the class as the
scope.

For example with the default format string:

    
    
        test string: "fix(User): ensure email address is required"
        format:      "%{type}(%{scope}): %{description}"
        [type: "fix", scope: "User", description: "ensure email address is required"]
    

So any literal characters are matched exactly and anything inside the
capturing %{...} is assigned to that variable.

This does fall over in the following case:

    
    
        "fix():(User): ensure email address is required"
        "%{type}(%{scope}): %{description}"
        [type: "fix", scope: "):(User", description: "ensure email address is required"]
    

It is certainly a candidate for improvement in the future.

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Myrmornis
After the PR is opened is too late to warn about commit messages. They can't
be changed without a destructive push to the remote, which is generally a no-
no for a public branch, and when using github, closes the PR automatically.
The correct place to do this is, I believe, in the `commit-msg` hook:
[http://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks](http://git-
scm.com/book/en/v2/Customizing-Git-Git-Hooks)

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iandanforth
Slightly off topic - are there any good plugins/tools that remind you to
commit frequently? I'd love something like this for sublime.

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akoeplinger
Have you thought about opening this up for more than just commit messages?

Many projects need to check a number of things on PRs, e.g. enforce coding
style, bugfix has a corresponding test, user signed the CLA, owner of %{scope}
is notified for review, etc. That would obviously need a way to tie into
external/custom tools as everybody validates these things differently.

~~~
Gazler
Thanks for the ideas.

I think there are several avenues that could be explored with this. I wanted
to stay away from explicitly checking the code initially, as there are other
tools aimed at that specific task, however there is no reason something like
this couldn't be added into GitCop at a later date.

I had the idea of checking that the user exists in a list of users by
specifying a JSON list of users. This means that it could be used to check if
a CLA has been signed, but there are other applications too. Does this seem
like a reasonable way to do it?

I like the idea of ensuring a test has been added, not sure how to tackle it,
but it is certainly worth keeping in mind.

~~~
akoeplinger
I think what I was aiming at is integration with other tools, rather than
adding those checks directly into GitCop (as you said, there are already
services that check code, validate CLA etc).

Or maybe provide me with a Travis-like sandbox where I can run my checks with
whatever linter/validator/custom code I want and report the results back?

Just fleshing out some ideas here :)

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tokenrove
I like the idea, but for projects that aren't open source, why not just
mandate the use of a git commit-msg hook instead?

~~~
Gazler
A git hook would certainly work for this as you described and I would
certainly encourage people to investigate that route if it is appropriate for
them. [http://git-scm.com/book/en/v2/Customizing-Git-Git-Hooks](http://git-
scm.com/book/en/v2/Customizing-Git-Git-Hooks)

The goal for GitCop is to be fast and easy to set up in a way that integrates
well into a GitHub pull request based flow.

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rurounijones
By that point isn't it too late? Or do you expect people to commit --amend and
force push?

~~~
Gazler
It is common in many flows to expect people to do a force push if something is
wrong with their pull request, e.g. having 15 commits that look like:

    
    
        Try stuff
        Another prototype
        Fix something
        ...
        Revert prototype
    

It is fairly common (in my experience) for the contributor to be asked to
squash those commits.

In my opinion, the more guards in place the better.

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tjbiddle
Looks clean, has plenty of features, and I love the pricing schema (Unlimited
for open source projects - Always been a fan of this trend).

Great work!

~~~
Gazler
Thanks for the feedback, I am a fan of the pricing schema too!

An example of the messages GitCop outputs can be seen at
[https://github.com/Gazler/gitcop-
test/pull/2](https://github.com/Gazler/gitcop-test/pull/2) if you are
interested.

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thestonefox
What an awesome service, I'm signing up my dev team for this right now! Worth
the money!

~~~
Gazler
Thanks for the feedback, I hope your dev team find it as valuable as you do.

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dmooney1
I'd love it if you could make this work with Atlassian Stash behind a
firewall.

~~~
mindsocket
Stash has a number of integration points where similar checks could be
applied, the most similar to GitCop being a merge check. That said, a pre-
receive hook would make a lot more sense.

Disclosure: I work for Atlassian

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jimmyboyb
I have been looking for something like this

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warrenmcwin
looks like Robocop has finally joined the Pull Police. nice job!

