Re: [Wikitech-l] Let's talk about arc: Phabricator replacement for git-review and more
Definitely -- it's less clear than it could be because I don't call out --no-ff explicitly (I'm hedging my bets against Mercurial adding something similar some day), but for all practical purposes I mean --no-ff when I say having a strict policy where your master/trunk contains only merge commits and or create an abstraction layer (merge commits). On Aug 10, 2012, at 8:29 PM, Daniel Friesen wrote: On Fri, 10 Aug 2012 17:06:12 -0700, Evan Priestley epriest...@phacility.com wrote: [...] That said, there is also a (purely advisory) document here extolling the virtues of amending (if not during development, at least before pushing changes to the remote): http://www.phabricator.com/docs/phabricator/article/Recommendations_on_Revision_Control.html Looks to me like the same mistakes I see all the time. ie: Thinking about commit history as a single linear tree. Almost none of the arguments in the Why section are valid when you --no-ff instead of squashing. -- ~Daniel Friesen (Dantman, Nadir-Seen-Fire) [http://daniel.friesen.name] ___ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l ___ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
Re: [Wikitech-l] Let's talk about arc: Phabricator replacement for git-review and more
Daniel Friesen li...@nadir-seen-fire.com wrote: Why is arc written in PHP? That seems to be a horrible software decision to me. Core extensions not enabled by default can be hard to install on some OS. And imho the packaging setup is not as good. Frankly I gave up trying to get mcrypt installed on either version of php installed on my Mac. It could be improved to check for curl and bcmath (the ones I found out are needed) on startup, not during some other command after other succeded (unless of course the extension is needed only for some specific operation not applicable to general public). This one I find interesting: arc looks as if it works completely with patches on it's own rather than doing anything with git. I can't see how phabricator can have commit workflow support any better than gerrit when it appears to take the repo completely out of the question. Erik also wrote this earlier: As I understood it, the big gotchas for Phabricator adoption are that Phabricator doesn't manage repositories - it knows how to poll a Git repo, but it doesn't have per-repo access controls or even more than a shallow awareness of what a repository is; it literally shells out to git to perform its operations, e.g. poll for changes - and would still need some work to efficiently deal with hundreds of repositories, long-lived remote branches, and some of the other fun characteristics of Wikimedia's repos. Full repo management is on the roadmap, without an exact date, and Evan is very open to making tweaks and changes as needed, especially if it serves a potential flagship user like Wikimedia. After Gerrit, I think it might actually be a GoodThing(tm) to detach the code review tool from managing the repository. Git at its core is a tool to quickly snapshot directories. Blobs are its first-class objects, not patches or diffs (this is I think pretty innovative looking at the traditional version control systems). I think there is a reason why Linus settled with email patch workflow that is even included in the git user interface. Keeping patches and commits separately starts making sense to me - otherwise one ends up in rebase hell. //Saper ___ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
Re: [Wikitech-l] Let's talk about arc: Phabricator replacement for git-review and more
On Fri, 10 Aug 2012 00:52:33 -0700, Marcin Cieslak sa...@saper.info wrote: Daniel Friesen li...@nadir-seen-fire.com wrote: Why is arc written in PHP? That seems to be a horrible software decision to me. Core extensions not enabled by default can be hard to install on some OS. And imho the packaging setup is not as good. Frankly I gave up trying to get mcrypt installed on either version of php installed on my Mac. It could be improved to check for curl and bcmath (the ones I found out are needed) on startup, not during some other command after other succeded (unless of course the extension is needed only for some specific operation not applicable to general public). This one I find interesting: arc looks as if it works completely with patches on it's own rather than doing anything with git. I can't see how phabricator can have commit workflow support any better than gerrit when it appears to take the repo completely out of the question. Erik also wrote this earlier: As I understood it, the big gotchas for Phabricator adoption are that Phabricator doesn't manage repositories - it knows how to poll a Git repo, but it doesn't have per-repo access controls or even more than a shallow awareness of what a repository is; it literally shells out to git to perform its operations, e.g. poll for changes - and would still need some work to efficiently deal with hundreds of repositories, long-lived remote branches, and some of the other fun characteristics of Wikimedia's repos. Full repo management is on the roadmap, without an exact date, and Evan is very open to making tweaks and changes as needed, especially if it serves a potential flagship user like Wikimedia. After Gerrit, I think it might actually be a GoodThing(tm) to detach the code review tool from managing the repository. Git at its core is a tool to quickly snapshot directories. Blobs are its first-class objects, not patches or diffs (this is I think pretty innovative looking at the traditional version control systems). I think there is a reason why Linus settled with email patch workflow that is even included in the git user interface. Keeping patches and commits separately starts making sense to me - otherwise one ends up in rebase hell. //Saper Managing repositories and rebasing have absolutely nothing to do with each other. In fact the managing being discussed is talking about access controls and perhaps creating repos, etc... Git's storage of blobs rather than diffs is also irrelevant. There is nothing wrong with review being a tree of blobs noted as based off of the sha1 of a previous tree of blobs. Heck this is something that would make an overview diff of multiple commits inside of a review branch really sane. And Linus settled with an email patch workflow so he wouldn't have to write a new review system in addition to a whole vcs. It has nothing to do with whether changes for review in a review system a better as deltas or blobs. Linus is working with a hierarchical pull-request model with multiple lieutenant maintainers. Something we explicitly chose not to do. So his choices in that area have no bearing on what is the best way to do a review system. Rebasing has absolutely nothing to do with whether changes for review and actual commits are stored in the repo or separated from it. In fact, quite frankly, working with diffs instead of commits and then applying the diff to the latest version on commit is almost exactly the same as rebasing. Rebase hell is a screwed up workflow which is 100% by gerrit design. There was nothing about the model they chose to write a review system that forced them to use a rebase+patchset model. Rebases were their choice when they could have used real review heads with multiple commits and normal merges. The way a clean pull request model works, but with the automation we want. It is entirely possible to write a review system that integrates with git, stores all commits for review inside of the repo, does not use rebases, supports multiple commits in a review-head without making buggy commits part of the main line of master, support post-commit review as well, and doesn't fight git introducing ugly hacks or making non-git things do things git is supposed to be doing. And if I had the time (ie: backing) I'd write it. -- ~Daniel Friesen (Dantman, Nadir-Seen-Fire) [http://daniel.friesen.name] ___ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
Re: [Wikitech-l] Let's talk about arc: Phabricator replacement for git-review and more
On Aug 9, 2012, at 9:52 PM, Daniel Friesen wrote: Why is arc written in PHP? That seems to be a horrible software decision to me. Core extensions not enabled by default can be hard to install on some OS. And imho the packaging setup is not as good. Frankly I gave up trying to get mcrypt installed on either version of php installed on my Mac. This kind of tool screams out to me as something perfectly suited for python. It's pre-installed a lot of the time. IIRC most of the time you're not missing much you need. And python comes with easy_install and better yet pip. Please let us know when you run into specific problems. As far as I know, this hasn't been a major pain point in practice (some minor pain on Windows, but I think Python would be about as bad there). arc is written in PHP because Phabricator is written in PHP, and we can reuse more code more easily by having both the client and server in the same language. For example, the code to parse raw diffs lives in Arcanist, but Phabricator uses the same code when it needs to parse raw diffs (e.g., via copy and paste or from the VCS). In turn, Phabricator is written in PHP because it grew on top of a PHP stack at Facebook. But even before seeing this arc is related to the one thing about phabricator that concerns me the most. arc looks as if it works completely with patches on it's own rather than doing anything with git. ie: It looks as if it takes the actual source repo completely out of the story for patch submission. For pre-push review, the remote repository is completely out of the story, yes. However, in pre-push review the changes aren't available in the remote, so I believe this is the only reasonable architecture. For post-push review in Phabricator (which does not use arc) the local is completely out of the story. I can't see how phabricator can have commit workflow support any better than gerrit when it appears to take the repo completely out of the question. I'm not sure I understand this concern, can you give me an example of what you mean? (e.g., what features does gerrit have that Phabricator can't?) Evan ___ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
Re: [Wikitech-l] Let's talk about arc: Phabricator replacement for git-review and more
On Aug 10, 2012, at 12:52 AM, Marcin Cieslak wrote: It could be improved to check for curl and bcmath (the ones I found out are needed) on startup, not during some other command after other succeded (unless of course the extension is needed only for some specific operation not applicable to general public). We should be checking for curl on startup (and a few other things -- namely JSON and a reasonable PHP version). Was this not your experience? The expectation is that you'll receive this error if curl is not installed: $ arc PHP CONFIGURATION ERRORS You need to install the cURL PHP extension, maybe with 'apt-get install php5-curl' or 'yum install php53-curl' or something similar. bcmath is used only to encode binaries in base85 for git patches when you generate, apply or export a changeset that includes binaries to a git patch format or working copy, but we're definitely not doing a good job of managing this dependency right now; I filed https://secure.phabricator.com/T1635 to track it. Thanks! Evan ___ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
Re: [Wikitech-l] Let's talk about arc: Phabricator replacement for git-review and more
Evan Priestley epriest...@phacility.com wrote: On Aug 10, 2012, at 12:52 AM, Marcin Cieslak wrote: It could be improved to check for curl and bcmath (the ones I found out are needed) on startup, not during some other command after other succeded (unless of course the extension is needed only for some specific operation not applicable to general public). We should be checking for curl on startup (and a few other things -- namely JSON and a reasonable PHP version). Was this not your experience? I have already had php-curl installed and I only noticed I needed it because the need to configure list of acceptable CAs; so I *knew* php-curl is needed. PHP without bcmath failed on me badly with PHP fatal error. //Marcin ___ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
Re: [Wikitech-l] Let's talk about arc: Phabricator replacement for git-review and more
On Fri, 10 Aug 2012 05:52:16 -0700, Evan Priestley epriest...@phacility.com wrote: On Aug 9, 2012, at 9:52 PM, Daniel Friesen wrote: Why is arc written in PHP? That seems to be a horrible software decision to me. Core extensions not enabled by default can be hard to install on some OS. And imho the packaging setup is not as good. Frankly I gave up trying to get mcrypt installed on either version of php installed on my Mac. This kind of tool screams out to me as something perfectly suited for python. It's pre-installed a lot of the time. IIRC most of the time you're not missing much you need. And python comes with easy_install and better yet pip. Please let us know when you run into specific problems. As far as I know, this hasn't been a major pain point in practice (some minor pain on Windows, but I think Python would be about as bad there). arc is written in PHP because Phabricator is written in PHP, and we can reuse more code more easily by having both the client and server in the same language. For example, the code to parse raw diffs lives in Arcanist, but Phabricator uses the same code when it needs to parse raw diffs (e.g., via copy and paste or from the VCS). In turn, Phabricator is written in PHP because it grew on top of a PHP stack at Facebook. But even before seeing this arc is related to the one thing about phabricator that concerns me the most. arc looks as if it works completely with patches on it's own rather than doing anything with git. ie: It looks as if it takes the actual source repo completely out of the story for patch submission. For pre-push review, the remote repository is completely out of the story, yes. However, in pre-push review the changes aren't available in the remote, so I believe this is the only reasonable architecture. This holds true for centralized version control systems where the only actual commits are ones that have made it into the centralized repo. But IMHO it does not hold true for dvcs' like Git. Git handles commits and refs really nicely. It is entirely possible to have the change available inside the remote even when the change is not merge into the actual repo. In fact this is hugely advantageous. You have practically none of the downsides that making the actual commit would have. But you have almost every single advantage you could possibly have by having it in the repo: - You get all the tools you need for free. There is no need to re-implement anything that already exists inside the vcs. - Dependencies, deltas, merges, handling conflicts, etc... everything is already handled for you. - Because the commit already exists you can already start making new commits based on it before the commit even gets merged into the repo. The review system doesn't interfere with the development process. And this is possible without the use of any specialized tools. - Because the commit is in the repo you can freely pull the commit anywhere you want, cherry-pick it, merge it into another branch, write code based off of it, etc... natively using all the standard tools without any unnecessary custom tool. For post-push review in Phabricator (which does not use arc) the local is completely out of the story. I can't see how phabricator can have commit workflow support any better than gerrit when it appears to take the repo completely out of the question. I'm not sure I understand this concern, can you give me an example of what you mean? (e.g., what features does gerrit have that Phabricator can't?) I wouldn't really say Gerrit does this right. Rather I believe that Gerrit does this wrong, that's the reason we're trying to ditch Gerrit, but Phabricator looks as if it might not do it any better so I can't see why it would be an improvement. Perhaps this would be best served by you explaining how things would work in Phabricator for two situations: First situation: - Someone makes a change to core - Then they submit it for review - A reviewer notes that there is something wrong with the code that needs to be fixed - Someone fixes the code - Then they update the review (*This is usually the important point where review systems differ) - The change is accepted and merge into the repo In the gerrit situation: - The change to core is committed as a local commit with a Change-ID - Submission for review is done with `git review -R` - [A reviewer notes that there is something wrong with the code that needs to be fixed] - An --amend is done to edit the commit. - `git review -R` updates the review adding a new patchset to replace the one in gerrit. - Gerrit merges one commit into the repo The ideal situation IMHO: - The change is committed as a local commit using normal git tools - *I won't go into the ideal submission process. - [A reviewer notes that there is something wrong with the code that needs to be fixed] - A local commit is made on top of the previous
Re: [Wikitech-l] Let's talk about arc: Phabricator replacement for git-review and more
First situation (updates) You can update a Differential Revision with any new change you want -- including a change from another project or repository, or a raw diff you typed by hand, or whatever else. You do not need to structure the new change in any special way or relate it to the previous change whatsoever. This isn't terribly common (usually new changes are amended versions of old changes, or old changes plus new commits), but handles situations like: - User A makes a change to fix a bug in the Y extension. - User B says this is good, but we should fix the root cause in the X library, not the symptom here in the Y extension. - User A updates the same revision with a change to the X library instead. In Differential, Revisions are about goals and ideas (fix this bug), not specific commits. You do not need to amend commits to send changes for review, and are free to represent them locally in whatever form you prefer. Depending on configuration, some workflows will amend commit messages for you (arc diff, arc amend) or perform --squash merges instead of --no-ff merges (arc land). You can customize these behaviors with configuration. Some discussion here: http://www.phabricator.com/docs/phabricator/article/Arcanist_User_Guide_Configuring_a_New_Project.html#history-mutability That said, there is also a (purely advisory) document here extolling the virtues of amending (if not during development, at least before pushing changes to the remote): http://www.phabricator.com/docs/phabricator/article/Recommendations_on_Revision_Control.html However, we fully support immutable history workflows if you prefer them: you do not ever need to amend or rebase anything. Second situation (changes based on unreviewed code) Phabricator treats changes based on unreviewed code no differently from changes based on reviewed code -- at a basic level, you can paste in any arbitrary diff file if you want, and it works without additional context. If additional context is available, it just stores and presents more metadata and improves workflows. Making changes that are based on unreviewed code is very common in Phabricator workflows. The intent is for code review to block only when it actually needs to (e.g., you need feedback from peers to proceed because you aren't sure about something). Making it easy to continue work without review also encourages smaller, more reviewable diffs. On Aug 10, 2012, at 9:47 AM, Daniel Friesen wrote: On Fri, 10 Aug 2012 05:52:16 -0700, Evan Priestley epriest...@phacility.com wrote: On Aug 9, 2012, at 9:52 PM, Daniel Friesen wrote: Why is arc written in PHP? That seems to be a horrible software decision to me. Core extensions not enabled by default can be hard to install on some OS. And imho the packaging setup is not as good. Frankly I gave up trying to get mcrypt installed on either version of php installed on my Mac. This kind of tool screams out to me as something perfectly suited for python. It's pre-installed a lot of the time. IIRC most of the time you're not missing much you need. And python comes with easy_install and better yet pip. Please let us know when you run into specific problems. As far as I know, this hasn't been a major pain point in practice (some minor pain on Windows, but I think Python would be about as bad there). arc is written in PHP because Phabricator is written in PHP, and we can reuse more code more easily by having both the client and server in the same language. For example, the code to parse raw diffs lives in Arcanist, but Phabricator uses the same code when it needs to parse raw diffs (e.g., via copy and paste or from the VCS). In turn, Phabricator is written in PHP because it grew on top of a PHP stack at Facebook. But even before seeing this arc is related to the one thing about phabricator that concerns me the most. arc looks as if it works completely with patches on it's own rather than doing anything with git. ie: It looks as if it takes the actual source repo completely out of the story for patch submission. For pre-push review, the remote repository is completely out of the story, yes. However, in pre-push review the changes aren't available in the remote, so I believe this is the only reasonable architecture. This holds true for centralized version control systems where the only actual commits are ones that have made it into the centralized repo. But IMHO it does not hold true for dvcs' like Git. Git handles commits and refs really nicely. It is entirely possible to have the change available inside the remote even when the change is not merge into the actual repo. In fact this is hugely advantageous. You have practically none of the downsides that making the actual commit would have. But you have almost every single advantage you could possibly have by having it in the repo: - You get all the tools you need for free. There is no need to
Re: [Wikitech-l] Let's talk about arc: Phabricator replacement for git-review and more
On Fri, 10 Aug 2012 17:06:12 -0700, Evan Priestley epriest...@phacility.com wrote: [...] That said, there is also a (purely advisory) document here extolling the virtues of amending (if not during development, at least before pushing changes to the remote): http://www.phabricator.com/docs/phabricator/article/Recommendations_on_Revision_Control.html Looks to me like the same mistakes I see all the time. ie: Thinking about commit history as a single linear tree. Almost none of the arguments in the Why section are valid when you --no-ff instead of squashing. -- ~Daniel Friesen (Dantman, Nadir-Seen-Fire) [http://daniel.friesen.name] ___ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
[Wikitech-l] Let's talk about arc: Phabricator replacement for git-review and more
I just wrote a very rough and quick walkthrough how to get that tool running: https://www.mediawiki.org/wiki/Arcanist My first impression is very good. The UI is very nice (it guides you when it needs to, it just does the job if all is fine). The user's guide is unfortunately poor. I don't know yet how to avoid this warning: This diff is for the 'E3Experiments' project but the working copy belongs to the '' project. I see that arc can be also installed as the git pre-receive hook, but it needs some project configuration for that. Interesting. Anyway, I managed to download one change: $ git branch -vv * arcpatch-D3 be7cfd9 Merge branch 'master' of ssh://gerrit.wikimedia.org:29418/mediawiki/extensions/E3Experiments into munaf/pef2 master e40fce0 [origin/master] Rename events.js - communityClicks.js //Saper ___ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
Re: [Wikitech-l] Let's talk about arc: Phabricator replacement for git-review and more
I sent out a diff to fix the error message (https://secure.phabricator.com/D3231), the new one reads: This patch is for the 'phabricator' project, but the working copy does not have an '.arcconfig' file to identify which project it belongs to. Still try to apply the patch? We're trying to catch the case where you're attempting to apply a patch to the wrong project -- I'm guessing revision D3 was made in a working copy with a .gitignored .arcconfig file that associates it with E3Experiments. If you check in the .arcconfig file, arc will be able to recognize the working copy's project and will stop complaining. What could we improve about the user guide? Evan On Aug 9, 2012, at 6:15 PM, Marcin Cieslak wrote: I just wrote a very rough and quick walkthrough how to get that tool running: https://www.mediawiki.org/wiki/Arcanist My first impression is very good. The UI is very nice (it guides you when it needs to, it just does the job if all is fine). The user's guide is unfortunately poor. I don't know yet how to avoid this warning: This diff is for the 'E3Experiments' project but the working copy belongs to the '' project. I see that arc can be also installed as the git pre-receive hook, but it needs some project configuration for that. Interesting. Anyway, I managed to download one change: $ git branch -vv * arcpatch-D3 be7cfd9 Merge branch 'master' of ssh://gerrit.wikimedia.org:29418/mediawiki/extensions/E3Experiments into munaf/pef2 master e40fce0 [origin/master] Rename events.js - communityClicks.js //Saper ___ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l ___ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
Re: [Wikitech-l] Let's talk about arc: Phabricator replacement for git-review and more
On Thu, 09 Aug 2012 18:15:45 -0700, Marcin Cieslak sa...@saper.info wrote: I just wrote a very rough and quick walkthrough how to get that tool running: https://www.mediawiki.org/wiki/Arcanist My first impression is very good. The UI is very nice (it guides you when it needs to, it just does the job if all is fine). The user's guide is unfortunately poor. I don't know yet how to avoid this warning: This diff is for the 'E3Experiments' project but the working copy belongs to the '' project. I see that arc can be also installed as the git pre-receive hook, but it needs some project configuration for that. Interesting. Anyway, I managed to download one change: $ git branch -vv * arcpatch-D3 be7cfd9 Merge branch 'master' of ssh://gerrit.wikimedia.org:29418/mediawiki/extensions/E3Experiments into munaf/pef2 master e40fce0 [origin/master] Rename events.js - communityClicks.js //Saper Why is arc written in PHP? That seems to be a horrible software decision to me. Core extensions not enabled by default can be hard to install on some OS. And imho the packaging setup is not as good. Frankly I gave up trying to get mcrypt installed on either version of php installed on my Mac. This kind of tool screams out to me as something perfectly suited for python. It's pre-installed a lot of the time. IIRC most of the time you're not missing much you need. And python comes with easy_install and better yet pip. But even before seeing this arc is related to the one thing about phabricator that concerns me the most. arc looks as if it works completely with patches on it's own rather than doing anything with git. ie: It looks as if it takes the actual source repo completely out of the story for patch submission. I can't see how phabricator can have commit workflow support any better than gerrit when it appears to take the repo completely out of the question. -- ~Daniel Friesen (Dantman, Nadir-Seen-Fire) [http://daniel.friesen.name] ___ Wikitech-l mailing list Wikitech-l@lists.wikimedia.org https://lists.wikimedia.org/mailman/listinfo/wikitech-l
