What mechanism does git use to find its repository? - linux

I have several git repositories. One of these is in $PATH. Today, I accidentally moved to a directory that I thought had a git repository, but did not have one.
cd <another_directory_without_.git>.
So, when I entered git status, the output was confusing.
It appears git found the repository in $PATH, so in this case, git found the repository in ~/bin, which is in my PATH.
Does git search for repositories by looking in $PATH, or is there another search mechanism at work?

I can't find a definitive reference for the actual details, but we can infer most of it from the documentation to the git repository variables.
Git looks for its a repository, by order of preference:
in a directory provided by the --git-dir argument
in a directory provided by the GIT_DIR environment variable
in subdirectory .git or the current directory
in subdirectory .git of an ancestor directory. Environment variables GIT_CEILING_DIRECTORIES and GIT_DISCOVERY_ACROSS_FILESYSTEMS set a few constraints on that.

According to the git(1) manual page, Git goes like this when it looks for its object store:
If the "--git-dir" command-line option was specified its value is used to locate the repository.
If the GIT_DIR environment variable is available and set its value is used to locate the repository.
Note that in both of these cases no search/heuristics is done.
Otherwise Git tries to figure out if the current directory is the repository — in case it's a bare repository which has no work tree.
The logic it uses to carry out this task is explained here. To cite it:
Test if it looks like we're at a git directory.
We want to see:
- either an objects/ directory _or_ the proper
GIT_OBJECT_DIRECTORY environment variable
- a refs/ directory
- either a HEAD symlink or a HEAD file that is formatted as
a proper "ref:", or a regular file HEAD that has a properly
formatted sha1 object name.
Failing that, Git tries to find a directory named ".git" in the current directory.
If it succeeds, it uses the test from the previous step to verify if it's really what it was looking for.
If it fails, it ascends one level up — to the parent directory and tries again.
The last two steps are carried out until / on POSIX-like systems or the root of the drive — on Windows is hit (and hence there's nothing to ascent). By default, Git also won't cross the boundary of a filesystem of the current directory.
As you can see, no $PATH is involved: this directory is used only to look up executable programs, and Git has no business with it.

Related

How can I add a .git directory to a git repository?

I am doing unit tests on a python program who, for QA purposes, gets the repository name and the current commit hash from the .git in the directory
For my unit tests on that program I would like to have a dummy .git directory in the tests directory. That .git repository would have a single initialization commit and a remote that would not be used
When attempting to add a .git to my tool's repository, git seems to ignore it and indicates that there are no differences in the status and commit
How can I add the .git directory to my project repository ? Something like tests/.git
You can't do that. It's inherently forbidden by Git.
You can store a tar or ZIP archive that contains the repository, and then have your test routine extract it to a temporary location. If you go that route, I recommend to use an uncompressed archive format, because it allows Git's own compression algorithms to work more efficient.
I think we would need more details about what you want to achieve to provide like the best answer... but I think you should look at git bundle. You can track a bundle file and then use it to regenerate a git repo.

Git thinks a file within a symlinked directory has been deleted after recreating the symlink, how can I fix it?

I have a symlinked directory within my repository, which links to files elsewhere on the filesystem. For whatever reason, the symlink breaks every now and then, and it turns into a regular empty folder. So I deleted the empty folder, and recreated the symlink with ln -s ../../ ext, which appears to have worked as I can browse that folder and see the contents. But when I run git status, it appears all the files that should be visible within the ext folder are missing. How can I make git see that they are there again, within the symlinked directory?
This is on Ubuntu 18 by the way.
Your setup is odd, because Git does not follow symlinks, it just stores them.
That is, if you have a symbolic link ext -> ../.. and you run git add ext, Git creates, in the index, an entry with mode 120000 (symlink) to store the blob contents ../... Committing will create a commit that, when extracted, will create the symbolic link ext pointing to ../... Git will not store any files within ext when it is storing this symbolic link.
If, on the other hand, you have an existing commit that contains files named ext/foo and ext/bar, and you clone this repository at this commit, or extract this commit into a new and otherwise empty work-tree, Git will see that in order to write to files named ext/foo and ext/bar, your OS requires that ext exists as a directory. It will therefore create the empty directory ext, in which it will then create files foo and bar as your OS requires, so as to create files that to Git are merely named ext/foo and ext/bar. These two names, ext/foo and ext/bar, will now be in the index, so that the next commit you make will also contain these two files.
It sounds like you:
cloned a repository (perhaps with git clone --no-checkout?);
manually created a symbolic link in the work-tree named ext, pointing to some existing directory (perhaps one with some files inside it);
convinced git checkout to create ext/foo and ext/bar without first removing the symbolic link ext and replacing it with a directory ext.
This is not a supported mode of operation1 and you should not be surprised when it goes wrong.
1It leads to security issues: Git is meant not to write any files "outside" the work-tree area, and writing to files "under" a symbolic link to a directory outside the work-tree would allow this to occur. Rather than carefully limit symbolic link usage, Git just generally doesn't store files "beyond" any link in the first place—though it's probably possible, through careful manipulation of the index and, at the OS level, the file system in which your work-tree resides, to trick Git manually.
just dont put a repo in a repo, its not worth it

Where can I find for the location of the repos managed by Gitosis in Linux

We are using Gitosis in our Linux OS server to manage our projects. One time, I mistakenly pushed the config file which contains errors and then I wasn't able to push changes or clone copies of other projects from the server anymore, including gitosis-admin itself. Now, I need to login to the server using the root user and edit the config file there.
So, when I logged on to the server I saw these files:
Then I cd into gitosis-admin:
Then I cd again into gitosis-admin:
Then I vim the config file. This is what I see:
The content is obviously not what I am expecting, because I should have other repos listed in this config file.
I also double checked with git reflog to see the commit history:
Then I thought there might be another gitosis-admin located somewhere else so I search using the command: find / -type d -name 'gitosis-admin'
This is what I got:
The two directories are the ones that I checked. And they do not match the one I have in my local computer.
I tried searching for one of our projects but still I got no result at all.
Then I thought that the root might not have access to the repo files so I switched to the git user by executing the following command:
sudo git
But still, I can't find the directory of the repos.
So now, I need to know where are the repos located so that I might find the "real" gitosis-admin there.
You might be wondering am I checking on the wrong server here. So to prove that I am not mistaken, this is a screenshot of the host address that I am connected to:
This is the remote address of the gitosis-admin git repo shown in source tree:
A typical directory would be the repositories sub-directory of the git user's $HOME directory, that is
~git/repositories
It is possible to change this location using the repositories key of the gitosis section in the configuration file, which typically is a file named .gitosis.conf in the git user's home directory.
To answer the implied question (namely which file to fix to restore gitosis access), that would be ~git/.gitosis.conf as well.
(This is all documented in the gitosis repository's readme file.)

Are git commands supposed to be run under the working directory directly?

Suppose I have a git working directory, i.e. the directory which has a subdirectory called .git.
I wonder if the current directory matters when I run a git command.
Is it okay to run a git command
directly under the working directory
directly under some subdirectory of (subdirectory of) the working directory
directly under the parent directory of the working directory?
Consider
git commands which can take an argument which specifies some files, e.g. git add, and
git commands which doesn't take an argument that specifies some files, e.g. git pull, git push.
directly under the parent directory of the working directory?
Actually you can run it anywhere you want as long as you reference the git repo:
git --git-dir=/path/to/my/repo/.git add .
That means wherever you are (.: current folder) will be considered as your working tree. A
You can even specify your working tree:
git --work-tree=/a/path --git-dir=/path/to/my/repo/.git add .
In that latter case, you even can execute that last command anywhere you want. The '.' will be the work-tree /a/path.
Since git 1.8.5, you also have the -C option:
git -C /path/to/my/repo add .
Again, you can execute it anywhere you want, but the command will internally do a cd /path/to/my/repo first, and then execute the add .. That means the '.' will actually be /path/to/my/repo.
Finally, since git 2.5, a git repo supports multiple working trees, so you may execute your command in a folder which does not include a subfolder .git (but actually a kind of symbolic link to /path/to/my/repo/git)
It's OK to run both type of commands in both
directly under the working directory
directly under some subdirectory of (subdirectory of...) the working directory
Note, that you should use paths relative to directory where you are
You can't (by default) run any git command in parent directory. You'll get a message that you aren't in any repo.
I wonder if the current directory matters when I run a git command.
It does. git searches the current working directory for the .git subdirectory, and if it doesn't find it then it searches the parent directory, and so on until it finds it.
directly under the working directory
Yes.
directly under some subdirectory of (subdirectory of) the working directory
Yes.
directly under the parent directory of the working directory?
No, not by default. It is possible to tell git where to find the .git directory so that it doesn't search, but this is not the usual mode of operation.
Documentation on the relevant environment variables:
GIT_DIR is the location of the .git folder. If this isn’t specified, Git walks up the directory tree until it gets to ~ or /, looking for a .git directory at every step.
GIT_WORK_TREE is the location of the root of the working directory for a non-bare repository. If not specified, the parent directory of $GIT_DIR is used.
Source
git commands which can take an argument which specifies some files, e.g. git add, and
These commands need to know both where the .git directory is and the relative position of paths in the work tree.
git commands which doesn't take an argument that specifies some files, e.g. git pull, git push.
Commands like git push or git fetch need to know where the .git directory is, but don't care about the work tree. git pull does since it does a git merge which modifies files in the working tree.

Git clone without including top/parent folder

We have a repo in git where the project is contained in a folder called Project. We'd like to be able to release the code to a production server, by cloning the repo, without including the "Project" folder, but with everything below it. Is this possible? The destination directory name is /var/www, which is unrelated to anything in the project. Unfortunately I can't just do a symbolic link because of the nature of our hosting provider (which we'll change soon).
My answer take the assumption that you have a git repository whose content is the following:
/.gitignore
/Project
/Project/index.php
/ProjectB
/ProjectB/pom.xml
If you don't need history at all in that copy of your repository, there is the git archive command which can do what you want except its output its data in tar or zip format:
git archive [--format=<fmt>] [--list] [--prefix=<prefix>/] [<extra>]
[-o <file> | --output=<file>] [--worktree-attributes]
[--remote=<repo> [--exec=<git-upload-archive>]] <tree-ish>
[<path>…]
Like:
git archive --format=zip --remote=git#foobar.git master -- Project | unzip
However, the git clone command does not accept a repository path, and I think it's not really git like to export only a tree view of some branch. You would probably need a submodule making Project an independent git repository, or like the git archive example, get only what you want but without versioning (which can be questionable on a production server).
Instead, you can do that:
Clone your repository to whatever path, say /opt/foobar.
Create a symbolic link of /opt/foobar/Project in /var/www.
Or reference the /opt/foobar/Project in your apache configuration (to avoid the symlink) instead of plain /var/www.

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