We recently moved from Perforce to Mercurial and love it!
One little problem: after much research we can't figure out how to map a special directory in the repository to some special place on the client. Here is an example of our hg repo:
/foo/source files
/bar/source files
/build
/macosx/mac make files
/win/windows make files
With Perforce, we were using client spec mappings to map //depot/build/macosx/... to just /build/... on the Mac client, and //depot/build/win/... to /build/... on the Windows dev box. Directories foo and bar are synced as is. Makefiles in /foo and /bar assume that our build makefiles are located in /build and we would like to keep them as is. The final client set of files should look like this:
/foo/source files
/bar/source files
/build/client specific make files
I've read about subrepos, but this solution does not seem to be client specific.
Any idea how to solve this problem will be very much appreciated!
You can't check out only portions of a repository with Mercurial.
You always get a clone containing everything, and the working directory will also contain everything.
With Mercurial you should strive to have 1 repository for 1 project, so that everything you get logically belongs together, and then you shouldn't have much need for just a portion of it.
This also means that whatever directory structure you have in your Mercurial repository will always match exactly the structure you have on disk.
You can't do this with Mercurial as it doesn't have the concept of a client separate from a depot.
However, you can use a symlink on Mac OS X (ln -s) and a junction on windows (mklink on Vista and up using the junction tool on XP http://technet.microsoft.com/en-us/sysinternals/bb896768.aspx) to solve this problem on the file system level.
Alternatively you can use a variable in the Makefiles to refer to the build directory (eg $(BUILD)/something.ext instead of build/something.ext).
This sort of mapping cannot be done in Mercurial. There is an outstanding TODO item for 'narrow' clones so you can check out just a subdirectory. And I could see an implementation of that supporting that sort of functionality. But then again, I know that something like this would be considered a little too 'clever' (read complex) and there would be a lot of push-back on the idea.
In the meantime, I would suggest one of these two solutions.
Symbolic links. Put the symbolic link to your build directory in your .hgignore file. Then each person can make their own symbolic link to the appropriate directory of build files. This has the disadvantage of not working on a platform without symbolic links.
An environment variable that's used in a top level makefile to construct the path to the platform specific makefile it should be calling.
Related
We have a Mercurial repository with many projects, each resides in its own directory:
- Main Repo
- Project A
- Project B
- ...
Each of the projects is self contained and must reside in it's own directory, but there are some common files that should be similar between projects.
For example, some projects are websites, and they share a common javascript library we develop. When changing the library in one project, we would like it to change in other projects too, but the file must reside in each of the projects.
I read about sub-repos but they don't seem a good solution for this.
Is there a way to accomplish this in Mercurial?
You are looking for a feature for keeping the same file version in multiple places, also known as file cloning or file sharing in other types of source control, like Sourcesafe or Vault. There is no mechanism like this in Mercurial. Every file is a single entity with a single location.
The first solution you have is to keep the common libraries in a separate place. You need a single copy that can be accessed by all your projects. It does not matter if you use sub-repos or not, they can all be in the same repo, as long as your folder structure includes everything, but sub-repos can be easier to manage if your projects are not related.
The other solutions you have could be to state an internal policy to always sync and commit the common libraries manually (which I do not suggest as it is error-prone and requires effort), or to create a script, either as hook or not, to sync your files, before a commit or after an update (which is more tedious to establish and maintain anyway)...
Conclusion, go for the separation of your common libraries. You'll be glad you spent the extra time to set everything up correctly from the start.
Under Unix you could use soft-link (ln -s) for shared files and Mercurial will detect / save / create them. Just don't use absolute or empty path.
With Windows symbolic links won't work:
Tracking hard or symbolic links with mercurial on Windows
Bug 1825 - junction/parse point for windows directory symlinks
In my experience (local Linux repository) using symlinks to handle shared files works but it's usually better to create a library that contains the common files.
Even if you have one repository for all your projects, it is advised to have a separate library/tool/etc. repository(ies) for the common code(s).
The way you can "use" this code inside your project will then heavily depend on your technology and infrastructure: java/maven/ant world, linux distrib, ruby gems etc. You will generally have some kind of "dependencies specification" language where you can specify that you need such and such library. In a Gemfile for rails, using autoconf for C/C++ etc. Most of the time you can also specify a specific version (or greater than etc..) which allows taking care of API changes.
Basically it is not advised to solve this issue at SCM level but instead to use the right framework for decoupling your common code from the projects repositories.
There are one or two files, like .hgignore, which I generally want to be the same in each of a bunch of projects.
However, the nature of these files means that I can't simply move them to a common shared project and just make the other projects depend on that project. They have to be inside each project. Symbolic links are not an option either because some of our developers use Windows.
How can I share these files between repositories and have changes propagated across (on my local machine, at least)? I'm using Eclipse.
For your specific case of hgignore you can put an entry like this in each project's .hg/hgrc file:
[ui]
ignore.common = ~/hgignore-common
If you you know your common library will always the in the parent directory, as is often the case with a subrepo setup you could do:
[ui]
ignore.common = ../hgignore-common
or if you know it will always be in a sibling directory of project checkouts you could do:
[ui]
ignore.common = ../company-wide-defaults/hgignore-common
Unforunately there's no absolute way to reference a file that's valid everywhere, but you can at least to to a point where on your machine all your checkouts are referencing a common ignore.
Hardlinking instead of copying the relevant files sort of works with Eclipse - although you have to refresh each of the other projects to get it to pick up the change. However, you can configure Eclipse to watch the filesystem and automatically refresh whenever it needs to - I recommend this.
It does not work by default with Emacs, because Emacs breaks hard links (which is normally the right thing to do, but is not what you want in this case). However, you can disable this behaviour for multiply-linked files with (setq backup-by-copying-when-linked t).
I am writing a set of django apps and would like to use Hg for version control. I would like each app to be independent of the others so in each app there may be a directory for static media that contains images that I would not want under version control. In other words, the binary files would not all be in one central location
I would like to find a way to clone the repository that would include copies of the image files. It also would be great if when I did a merge, if there were an image file in one repo and not another, that there would be some sort of warning.
Currently I use a python script to find images and other binary files that are in one repo, but not the other. But a lot of people must face this problem, so there must be a more robust and elegant solution.
One one other thing...for reasons I do not want to go into, usually one of my repos is on a windows machine, and the other is on Linux. So a crossplatform solution would be nice.
Since Mercurial 2.0 the extension largefiles is now included in the main distribution. That extension keeps and manages large files outside of the "normal" repository in a way that you get the benefit of DCVS but without the benefit of exponential size and processing time growth.
Other extension that work along similar lines are SnapExtension and BigFilesExtension. However, those two are not distributed with Mercurial (you have to get them manually).
Mercurial can track any kind of file, for binary files if something changes then the whole file gets replaced not just the changes.
On the getting a warning if one repo doesn't contain a file, that's kind of the point of a DVCS is that the repos are related but are autonomous. You could always check and see what files were added during a synch or merge operation.
The current Mercurial book (by Bryan O'Sullivan) says, that Mercurial stores diffs also for binary files. How efficient this is, obviously depends on the nature of changes to binary files.
I'm trying to sell our group on using Mercurial as a source repository rather than VSS. In the process of updating our build scripts, I'm running into an issue trying to retrieve files from the Hg repository.
Our builds are automated with NAnt and currently work for local builds or builds from VSS (ie, pull the source as needed from VSS). I'm trying to update them to work with Mercurial as well.
Basically, when I'm working with single files, I don't have any issues since I can just use NAnt's 'get' task (after getting the appropriate revision hash) to retrieve the individual file.
The problem that I'm having is when I need to work with a directory (and subdirectories) of files that aren't at the root of the repository. I can't seem to figure out the proper commands to retrieve/copy a subdirectory from the repository to my 'working' directory for the builds. I've spent basically the whole afternoon trying to figure out how to do this with the mercurial executables (so I can use a NAnt 'exec' task), and have basically hit a wall so I figured I'd try posting here.
Can someone confirm whether this is possible, and provide some suggestions as to how I might be able to do this? I realize that Mercurial tracks changes by files and not directories, but it seems odd to me that this isn't available out of the box (from what I can tell).
If it's just not possible, the only workarounds I see are either maintaining NAnt fileset lists of expected files to work with (ugh!), or cloning the entire repository to a temporary directory and then just copying the files from that source as needed (this feels like a cludge to me).
I realize that I could simply create another repository for the directory that I want to work with, but I'd prefer to not go that route since I think that would increase the complexity of what I'm trying to do by a significant amount (I would have to apply this a large number of times for all of the different libraries that we build..).
Mercurial doesn't let you get only part of a repository. You have to get the whole tree. It's much more whole-repo focused than svn is.
You could try and segment your repository into multiple repos and manage them using the subrepos feature. Then you can pull the subdirectories independently.
So I'm pretty new to version control but I'm trying to use Mercurial on my Mac to keep a large Python data analysis program organized. I typically clone my main repository, tweak the clone's code a bit, and run the code on my data. If the changes were successful I commit and eventually push the changes back to my main repository. I guess that's a pretty typical workflow under version control.
My problem is that my code is run on the command-line, with several command-line arguments that refer to data files in the current working directory (and I have many such directories I need to test the code in, and they're outside of version control). So before using Mercurial I just kept my code in one ~/bin directory which was part of my PATH environment variable. Now, with version control, I need to either (1) after each edit, copy my current clone's executables to the ~/bin directory before running the code on the command line, or (2) each time I clone my code, add my current clone's path to the PATH, or (3) specify the entire/path/to/my/programs on the command line each time I run the code. None of these are very convenient, and I'm left feeling like there must be an elegant solution that I just don't know. Maybe something involving Mercurial's hooks? I want my under-revision code to be runnable on the command line between commits, so this seemed to rule out hooks, but I don't know... Many thanks for any suggestions!
Ry4an's answer is good if you want to continue with the multiple-clones workflow. But it's also worth being aware that Mercurial's powerful enough to allow you most of the benefits of that workflow without ever leaving your single "main" repo. I.e. you can create branches (named or anonymous) for experimental features, easily "hg update" to whatever version of the code you want to test, even use the mq extension to prune branches that didn't work out.
What I do in such a case is set up a two deep chain of symlinks to my binary in my current clone. For example I'll have:
/usr/bin/myappname
which is a symlink to
/home/me/repos/CURRENT/bin/myappname
where /home/me/repos/CURRENT is a symlink to whatever my current working clone is, for example:
/home/me/repos/myproject-expirment
After setting up the initial /usr/bin/myappname symlink all I have to do is update the CURRENT symlink when I create a new clone on which I'm working.