change mtime on git pull - linux

Does anybody know way to change mtime to repo commit time (or any other, but depends on commit metadata) for added/updated files?
We have some logic, which tests files mtime, but backend servers have different mtime on files which were changed, because of this we have some bugs.

Assuming you are getting updating/adding files when you do a git fetch, you can create a git-rebase-and-touch script file that does the rebase for you along with touching all files/directories in each new revision.
The script would look like:
#!/bin/bash
saveIFS=${IFS}
IFS=$'\n'
startrev=$(git rev-parse HEAD)
git rebase
for rev in $(git rev-list --reverse ${startrev}..HEAD); do
stamp=$(git log --pretty="%aD" ${rev}~..${rev})
IFS=$'\n'
for filename in $(git diff --name-only ${rev}~..${rev}); do
file=""
IFS='/'
for part in ${filename}; do
file=${file}/${part}
file=${file#/}
touch -c --date="${stamp}" "${file}"
done
done
done
IFS=${saveIFS}
If you currently use git pull now, use git fetch instead.

It's bloody dangerous tweaking file timestamps, and it's even more dangerous to assume, as you're doing here, that a timestamp means something other than what it ordinarily means. With anything, not just timestamps, doing that hurts reliability and maintainability, it makes comprehension and auditing difficult. The files changed for a legitimate reason, and your system broke.
The timestamps you want to check are recorded in commit metadata, and getting to them isn't efficient enough. Switch to extracting the timestamps to an index file or some such and check them there. Otherwise you're reduced to telling people learning your setup that "not everything is what it seems to be".

Related

find all lines with specific phrase in specific commit

Lets assume I have a commit with a known hash, and the commit touches 1000 files of 5000 files of the project.
Among some of those files there was added the log message LOG_WARNING(...);, lets say 500 times. Which I want to replace by LOG_INFO(...);.
I don't want to replace all LOG_WARNING(...); in the project (lets say it has 10000 of them), just ones, related to the specified commit.
I'm ready to walk over each of 500 lines I have to modify, but I'm trying to avoid walking over 10000 existing log-lines in the codebase.
What is the best way (practice) to do it?
I would do it that way:
git show --name-only <commit> | xargs sed -i 's/LOG_WARNING/LOG_INFO/'
The git command give the filenames part of the commit.
xargs provides these files to sed which replaces the wanted pattern.
What did help to me:
git diff (...) > patchfile -- extract all changes of current commit to a patchfile
edit patchfile -- using any editing tool & script, but in the patchfile I had to deal with only LOG_WARNING of specified commit.
git reset --hard -- to get rid of the commit I'm going to modify
git apply patchfile -- applies "patch", containing exactly my commit, but with replacement I wanted to.
It does the job. And relatively quickly.

Apply all stashed changes within a subfolder

I had an awful list of old stashes
I have first removed the very old ones
git reflog expire --expire-unreachable=7.days refs/stash
I have one huge stash left, which contains many stashed changes. Some are to keep some other would damage my production system. I went through the diff
git diff stash#{0}^1 stash#{0}
and I know which ones are to keep
I could do
git checkout --patch stash#{0} -- myfilename
to unstash changes on myfilename and is working fine.
However, I have a large folder with many files with stashed changes inside. I would like to apply all of them but only within that subfolder.
I have tried to approach it using wildcards in ksh but I does not work
git checkout --patch stash#{0} -- myfolder/*
results in
error pathspec [...] did not match any files known to git
The solution does not need to be git based, can be a shell script to wrap git calls
Have you tried :
git checkout --patch stash#{0} -- myfolder
without the ending * ?
Chances are your shell expands myfolder/* before executing the git command, and lists the elements which currently exist on disk, which is probably not what you want.

How to remove all untracked submodules from local working directory?

On my project, there are two branches I'm working on (Develop and Release), each of which makes generous use of submodules. The Develop branch uses about twice as many submodules as Release, because it is where we test ideas.
When I switch branches from Develop to Release, the directories of Develop-specific submodules stay where they are, and so they become untracked. This makes things a bit confusing for me, because I do occasionally need to add or remove submodules from Release as well, and the git status message becomes a long list of untracked modules, some of which I want to use and some I don't.
What I would like to do is remove all untracked submodules from my project as soon as I switch from Develop to Release, so that I'm working with a "clean slate", (IE no untracked submodules sitting in my working directory).
I have found several solutions to removing individual submodules one at a time, such as here: How do I remove a submodule?
However solutions such as this assume that the git submodules are in use and being tracked (which they are not), and it is also a pain in the neck to remove them one at a time when I'm working with something like 15-20 submodules.
I have also tried piping linux commands like so:
git ls-files --others --exclude-standard | rm -rf
But the command does not appear to do anything. I have also tried using the same with git rm -rf, to no avail.
Does anyone know if there is an easy to remove all untracked git submodules from a working directory? Any advice anyone can share on this matter would be greatly appreciated. Thank you!
With some advice from helpful folks in the comments section, I determined that there is no obvious, non-tedious solution to this problem. Instead I created a bash script that does the job for me. Here it is, in case anyone else has the same issue:
#!/bin/bash
clear
git ls-files --others --directory --exclude-standard
echo
read -r -p "Are you sure you want to remove these untracked submodules? [y/N] " response
if [[ $response =~ ^([yY][eE][sS]|[yY])$ ]]
then
git ls-files --others --directory --exclude-standard | while read line; do
rm $line/.git &> /dev/null;
done
git clean -d -f
fi
Easy steps for people not super comfortable with Bash scripts:
Step 1: Copy the above script into a file and name it 'cleanUSM'. Save the file to /usr/bin. If you are having trouble saving it or finding /usr/bin, just save it to your current directory, and then use 'sudo mv cleanUSM /usr/bin/cleanUSM' to get it where it needs to go.
Step 2: From within your root directory, run the command 'cleanUSM'
Thanks to everyone who contributed!

Commit without add and how to see remote branch log

1.I'm new to git and would like to know what happen if I've a file which was modified and already staged in the past(but now modified again), and I want to commit the file using a command such as :
git commit -m "yada yada" ~/home/Dan/project/file_to_commit.py
Is this equivalent to doing:
a.git add ~/home/dan/project/file_to_commit.py
b.git commit -m "yada yada"
If not please explain.
2.How can I see the remotes branch commits logs?(pushes) without doing git pull?
Thanks
This might be better as two separate questions, and the second question is already answered correctly, but I'll take a stab at answering both. Before I start, though, I want to say that the path ~/home/Dan/project/file_to_commit.py is pretty suspect: it suggests that your git directory is /.git, which is not a good idea. I'm going to assume, below, that the .git directory is much further down and you're just adding project/file or file (and I'll trim the paths in the question).
Note that the TL;DR version of the first answer is that they're almost the same, and you only need to know about the difference in some edge cases. (Hence the existing answer from eleventhend is probably good enough for most purposes.)
Q1: Add and commit vs git commit path
... I've a file which was modified and already staged in the past (but now modified again), and I want to commit the file using a command such as:
git commit -m "yada yada" file_to_commit.py
Is this equivalent to doing:
git add file_to_commit.py
git commit -m "yada yada"
If not please explain.
No, it's not exactly equivalent. This is a little bit tricky and it will help a lot if we define some terms and get a few things pinned down a bit more.
Also, you say "already staged in the past (but now modified again)", which leaves a bit of ambiguity: did you do a git commit in between these operations? I'll address both the "yes" and "no" cases by describing the full, general case.
The index
First, we need to define git's index or staging area (it has even a few more names, e.g., cache as in git diff --cached, but "index" and "staging area" are the two most common terms). Git has a (one, single) standard index—let's call this "the" index, and when we want to refer to another, different index, we'll spell out which other one we mean. When you run most normal git commands, including git add, git updates this index.1
Next, we need to take some notes on what's actually in the index. Aside from some interesting but not relevant here cases like merges, and one thing I'm leaving out on purpose, in essence, the index has one entry per file that will be in the next commit.2 That is, suppose you've made a commit, or checked out some branch, so that your current commit, which is now in your work tree, has 100 files in it. (Your work tree may have additional untracked and/or ignored files, as long as it also has those 100 files.)
Using git add
When you run git add, git stores a new copy of each of the files being added into the repository, which it calls blob objects. It calculates a hash value for each blob as it adds it to the repository, then puts the new hash into the index.
When you run git commit—at least, without either paths or -a—git reads the index and uses that to form the new commit. If the new commit would have the same tree as the previous commit,3 git requires that you add the --allow-empty flag. (This doesn't mean that the index is empty, but rather that the index matches the index you'd get by re-checking-out the current commit. So --allow-empty might be the wrong name for this flag; it maybe should have been called --allow-same or allow-unchanged or some such.)
Hence, if you do git add path and then git commit -m message, you'll get a commit that uses the index as updated by the git add, which may have additional updates from before that git add. Since there's just the one entry per path, though, if you do:
... hack on foo.py ...
$ git add foo.py
$ echo '# add a final comment' >> foo.py
$ git add foo.py
$ git commit -m 'update foo'
there will only be one update to foo.py in the new commit.
So what's the difference?
I claimed above that git commit path (and git commit -a) is not exactly the same as doing the git add and then git commit. Let's look at the precise difference.
When you give path names (or -a) to git commit, git uses a new, different, temporary index. It starts by copying something—exactly what gets a bit complicated—to the temporary index, then it adds each file that is to be committed, then it makes a commit from the temporary index. Once the commit is done, git goes back to using the normal, ordinary index, and it updates the index. That is, after adding stuff to the temporary index and committing, it also adds to the regular index.
To see how this really works we need some examples. Suppose we have two files and we git add a change to one of them:
# assume file1 and file2 are in the HEAD commit
echo add stuff to file1 >> file1
git add file1
echo add stuff to file2 too >> file2
At this point, git status will tell us that we have changes to file1 that are staged to be committed, and changes to file2 that are not staged to be committed.
If we run git add file2; git commit, we'll get both updates in the new commit. Once the commit is done, git status will show there is nothing to commit. But if, instead, we do:
git commit -m message file2
and then run git status, we'll see that file1 is still staged and ready to commit. The commit we just made has only the change to file2.
This is because the git commit file2 command started by making a temporary index using the HEAD commit, adding file2, making the commit, and then updating the normal index with the new file2. This last bit is important: if git didn't copy the change back into the (regular) index, the index would still have the old version of file2, and the next commit would undo the change we just committed.
This copy-back step has an important side effect. Suppose that we have a complicated change to foo.py. For instance, suppose we went to fix a bug, and along the way we refactored a few functions. We've tested the fix and it works, so we did git add foo.py and were about to commit it:
... hack on foo.py ...
... test, hack more, test, until fixed ...
git add foo.py
git commit -m 'refactor foo.py and then fix a bug'^C
At this point we realized that we shouldn't commit both changes together: we should commit the refactored code first, and then commit the bug fix.4
Well, we've already git add-ed the refactored and fixed code, so it's safely stashed away in the index, right? (No, WRONG! Danger Will Robinson! But let's proceed, since this is an example.) So we can just undo the fix part, leaving only the refactoring, and commit that first:
... edit foo.py to remove just the fix ...
git commit -m 'refactor code to prep for bug fix' foo.py
Once that commit is done, we can commit the staged version:
git commit -m 'fix bug #12345' foo.py
Alas, git now tells us that there's nothing to commit. What happened to the carefully staged full-fix version of foo.py?
The answer is, git commit foo.py wiped it out. Git first added the refactor-only foo.py to a temporary index and committed that; but then it copied the refactor-only foo.py back to the regular index, losing our carefully staged full-fix version. We can either re-create it, or fish around in the repository for the "dangling blob" that is left behind because of this.
(This should probably be considered a bug in git, although it's not clear what to do with the staged but uncommitted version.)
git commit -a and/or paths: --only vs --include
Here I need to quote myself from just a moment ago. When using -a or paths, git commit starts by copying something—exactly what gets a bit complicated. If you look closely at the git commit documentation, you will find the -i or --include option (and a corresponding, but default, -o / --only option). These control what goes into the temporary index.
When using --include, git commit creates its temporary index from the current index. When using the default --only mode, git commit creates its temporary index from the HEAD commit.
(Because of the copy-back step at the end, the only way to see that both commands are in fact using a temporary index is to view the index in the middle of the commit operation. If we use --include and check after the commit is done, the regular index will match the new HEAD commit, as if git commit were adding to the regular index rather than to the temporary index. Fortunately it's very easy to view the regular index "in the middle", by not supplying the -m flag, so that git commit fires up the editor. While that's going on, run git status in another window, or using job control. Here's an example:
# At this point I've modified both a.py and mxgroup.py
# but have not `git add`ed either one.
$ git add a.py
$ git status --short
M a.py
M mxgroup.py
# We see that a plain "git commit" would commit a.py,
# but not mxgroup.py.
$ git commit -i mxgroup.py
# now waiting in the editor
# Now, in another window:
$ git status -s
M a.py
M mxgroup.py
This shows that the (regular) index is still set up the way we had it. Once we write the message out and exit the editor, the commit process will update the regular index for the new mxgroup.py entry, and the now-committed a.py change is also in the new HEAD commit, so git status will show neither file.)
Q2: Viewing logs
How can I see the remotes branch commits logs?(pushes) without doing git pull?
Git itself operates almost entirely locally. You may be able to do this directly with web viewers, but it's pretty convenient to just do locally, by first running git fetch.
The git pull command is actually meant as a convenience. There are two steps needed to incorporate other people's commits:
obtain those commits so that you have them locally; and
merge or rebase using those commits.
These two steps are handled by different git commands: git fetch does step 1, and git merge and git rebase—you must pick one of the two—does whichever version of step 2 you want.
The git pull command simply does step 1, then does step 2. It chooses merge unless you instruct it otherwise. For historical reasons, it has multiple ways of choosing which operation to run in step 2.
My recommendation is that as a newbie to git, you avoid git pull entirely. There are two reasons for this, only one of which is valid today (unless you're stuck with very old versions of git):
Traditionally, git pull has had various bugs, some of which can even lose work. (As far as I know these are all fixed since git 2.0.)
While it is convenient, git pull obscures what's happening and makes you choose merge-vs-rebase too early. It is true that rebase is almost always the right answer, but git pull defaults to doing merge, which means that its default is wrong for new users. Plus, of course, there's that "obscures what's happening" issue. If you knew about fetch and then rebase as separate steps, this question probably would not even have come up.
1The index is just a file, and you can find it in .git/index. You can make git use a different index by setting GIT_INDEX_FILE in the environment, but this is mainly meant for use by scripts like git stash.
2The cases I'm leaving out are:
Conflicted merges, which record up to three entries per path, using non-zero stage numbers. Once your resolve the conflict and git add the result, the nonzero stages are cleaned out and the normal stage-0 result is stored instead, and we're back to the normal, ready-to-commit case for that index intry.
Removing a file that is in the current commit (git rm, with or without --cached). This writes a special stage-0 entry marking the file as to-be-omitted, rather than simply removing the entry.
3If you're committing a merge, git allows the tree to match those of any or all parents, since the merge commit needs to record the multiple parents. The "empty" test is thus applied only to non-merge, single-parent commits. This is documented much better in modern git than it was in old versions of git, but it still has the wrong name.
4This has nothing to do with git itself. The idea here is to commit small, readable, understandable, and most importantly testable changes. Any time you find yourself writing up a commit as "do A and B, and fix C, and add D and E" it's an indication that you should probably split this into one commit per thing—in this case, about 5 separate commits.
[updated]
It is actually equivalent. When you commit a file directly, using git commit <filepath>, it stages the current file before committing. You do have to stage the file the first time the file is added before committing it (tell the repository to start tracking the file) using git add <file>.
Sample workflow:
git add <file>
Make some changes, yada yada
git commit -m "yada yada" <file>
Make some more changes, blah blah
git commit -m "blah blah" <file>
2.
To see the commit logs of a remote git repository, first use git fetch on the repository, then run git log <path/branch> to view the log.
See here: https://github.com/abhikp/git-test/wiki/View-the-commit-log-of-a-remote-branch

Moving a git repo to another server

I have a git clone/repo on a development server, but I am now moving to another one. I don't want to commit all my local branches and changes to the main repository, so how can I make an exact copy of everything on oldserver to newserver?
I tried oldserver:~$ scp -rp project newserver:~/project
but then I just get loads and loads of "typechange" errors when trying to do anything on newserver.
Someone said something about x-modes, but how can I preserve that when moving files between servers?
If you want a git solution, you could try
git clone --mirror <oldurl> <newurl>
though this is only for bare repositories.
If this is a non-bare repo, you could also do the normal clone, followed by something like this:
git fetch origin
git branch -r | grep '^ *origin/[^ ]*$' |
while read rb; do git branch --no-track ${rb#*/} $rb; done
git remote rm origin
The middle step can of course be done in 5000 different ways, but that's one! (note that the continuation line \ isn't necessary after the pipe in bash - it knows it needs more input)
Finally, I'd suggest using rsync instead of scp (probably with -avz options?) if you want to directly copy. (What exactly are these typechange errors?)
I've actually done this, and all I did was tar the repo up first and scp it over. I would think that scp -rp would work as well.
"Typechange" would normally refer to things like a symlink becoming a file or vice-versa. Are the two servers running the same OS?
You may also want to try the simple dumb solution -- don't worry about how the typechanges got there, but let git fix them with a reset command:
git reset --hard HEAD
That only makes sense if (1) the problems all pertain to the checked-out files (and not the repository structure itself) and (2) you haven't made any changes on newserver which you need to preserve.
Given those caveats, it worked for me when I found myself with the same problem, and it doesn't require you to think about git's internals or how well your file-transfer process is preserving attributes.

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