How can I get the last merged branch name in git - linux

How can i get the last merged branch name in git from the remote
Tried
git log --first-parent --merges -1 --oneline
But not getting the branch name
Please help

In general, you cannot.
A merge commit may have, as its commit message, text of the form merge branch foo or merge branch foo of someurl, but to read that message, you must obtain the commit from the remote. Even so, there's no guarantee that branch foo exists any more, or that the name means anything if it does exist. Merging really works by commit hash IDs, not by branch names; branch names may evanesce.
If you think you need a branch name here, you are probably doing something wrong. Branch names do make sense here in other version control systems, but in Git, depending on them is unwise.

Here is the command you need to give (change the branch name from origin/master to whichever branch you're checking merges for):
git log --merges origin/master --oneline --grep='^Merge' -1 | grep -oe "[^']*[^']" | sed -n 2p

I had quite a bit of a hard time trying to solve this issue.
I had to get this information for my CircleCi pipeline, and to solve my problem I used the GitHub cli.
Specifically the pr list command: https://cli.github.com/manual/gh_pr_list
The following command gives you all the information of the last PR you merged into main
gh pr list -s merged -B main -L 1
Then you need to manipulate the string and get only the branch name. Which is the text before "MERGED"
I took it splitting the string and taking the penultimate element.

Related

How to git ls-tree from a commit object?

From documentation, in order to use git ls-tree you need to pass the hash of a tree object. What if I want to obtain the same output of git ls-tree starting from a commit object.
I can obviously do it with something like this:
git ls-tree $(git cat-file -p my_commit | grep -oP "(?<=tree ).*")
But I feel like I am reinventing the wheel. Is there a git command that already does this?
No, git ls-tree takes a tree-ish object.
The "-ish" suffix here is important. Per the Cambridge Dictionary:
-ish suffix (QUITE)
used to form adjectives to give the meaning to some degree; fairly:
He had a sort of reddish beard.
She was oldish - about 60, I'd say.
We'll start at sevenish (= about seven o'clock).
In this case, "tree-ish" means like a tree. A tree, of course, is like a tree. But a commit is also like a tree since it has exactly one tree component; that means that you can unambiguously refer to that tree by simply using the commit itself.
So, just do git ls-tree <commit-ish>.

how to use "--no-ff --no-commit" using GitPython while merging?

When i use commandline git merge with --no-ff --no-commit works fine. But using GitPython i am unable to dos.
May be i am not finding a correct documentation or forums for the below equivalent operation using GitPython.
Am i missing any ?
command line:
git merge --no-ff --no-commit "<TAG Name> or <Feature branch>"
GitPython:
print(f"Merging from tag '{input_tag}' into 'master'...")
repo = Repo(constants.git_clone_local_path)
repo.git.checkout('master')
repo.git.pull()
repo.git.merge(f'--no-ff --no-commit {input_tag}')
# repo.git.merge(f'{input_tag}', no_ff=True)
print(repo.git.status())
print('Done')
Python gives below error
cmdline: git merge --no-ff --no-commit test_tag
stderr: 'error: unknown option `no-ff --no-commit test_tag'
usage: git merge [<options>] [<commit>...]
or: git merge --abort
or: git merge --continue
-n do not show a diffstat at the end of the merge
--stat show a diffstat at the end of the merge
--summary (synonym to --stat)
--log[=<n>] add (at most <n>) entries from shortlog to merge commit message
--squash create a single commit instead of doing a merge
--commit perform a commit if the merge succeeds (default)
-e, --edit edit message before committing
--cleanup <mode> how to strip spaces and #comments from message
--ff allow fast-forward (default)
--ff-only abort if fast-forward is not possible
--rerere-autoupdate update the index with reused conflict resolution if possible
--verify-signatures verify that the named commit has a valid GPG signature
-s, --strategy <strategy>
merge strategy to use
-X, --strategy-option <option=value>
option for selected merge strategy
-m, --message <message>
merge commit message (for a non-fast-forward merge)
-F, --file <path> read message from file
-v, --verbose be more verbose
-q, --quiet be more quiet
--abort abort the current in-progress merge
--quit --abort but leave index and working tree alone
--continue continue the current in-progress merge
--allow-unrelated-histories
allow merging unrelated histories
--progress force progress reporting
-S, --gpg-sign[=<key-id>]
GPG sign commit
--overwrite-ignore update ignored files (default)
--signoff add Signed-off-by:
--verify verify commit-msg hook
This should work
git.merge('args', no_ff=True)
replace 'args' by yours arguments like your branch...
I didn't find any links in the documentation. But this code worked for me.
repo = Repo(constants.git_clone_local_path)
repo.git.merge(<source_branch>, no_ff=True, no_commit=True)

Is there a way to use "git log --oneline" filtering by commit hash while keeping the branch names?

I was looking for a way to highlight a specific commit hash when using git log --oneline, and I managed to do that by using:
# consider that 000000000 is the first 9 digits of the commit hash
git log --oneline | grep --color=always -E '^|000000000' | less -R
This actually works in a very similar way to simply git log --oneline and it indeed highlights the commit 000000000. The only problem though, is that it ends up losing all the information regarding my branches that git log --oneline gives me.
Examples:
# input:
git log --oneline
# output:
000000000 (myRemote/myBranch) my commit message
# input:
git log --oneline | grep --color=always -E '^|000000000' | less -R
# output:
000000000 my commit message
While the latter example comes with a highlighted 000000000, it lacks the (myRemote/myBranch) information.
So, is there a way to modify the input I'm using so that I can get both the highlight and branch info?
You can add the flag --decorate to your log, it'll do the job, I just tried it (git version 2.21.0.windows.1).
Optionnally, you might want to make an alias to which you pass the hash as a parameter, for convenience :
git config --global alias.find '!f() { git log --oneline --decorate | grep --color=always -E "(^|${1})"; }; f'
...and then when you search for commit deadbea7dad, you just type
git find deadbea7dad

How to prevent git from committing two files with names differing only in case?

We develop in a mixed environment - some people work on Macs and some work on Linux. This has proven to be a bit of a challenge at times, as those people who work on Linux are used to having their filesystems be case sensitive, so there's no issue committing (accidentally or otherwise) multiple files differing just by case. (e.g. FileName.ext versus filename.ext)
However, when the people on Macs go to check out the repository, having a case-insensitive filesystem means that the two files - differing only in case - overwrite each other and cause general havoc.
I know that there are various git settings to help people on case-insensitive filesystems work better with case changes (e.g. core.ignorecase), but these don't solve the issue where there's two different files in the repository, only differing by case.
I realize that the only way to fix it is to make sure the Linux people don't commit the two files differing only in case in the first place. -- Is there some setting in git which will pop up a warning or error if a user on a case-sensitive filesystem attempts to commit file(s) which would be confused with each other on a case-insensitive filesystem?
There's nothing built in (although there should be, no doubt). What you can do is provide a pre-commit hook that verifies that all names are OK and prevents the commit if not.
This hook only needs to be run on the Linux box (although making it work on Linux and Mac is easy, it's just Windows with its default impoverished toolbox that is problematic). You might want to add it to a side branch and give the Linux folks instructions on setting it up.
You may want to check branch names as well, as in git pre-commit or update hook for stopping commit with branch names having Case Insensitive match. (Interesting: the answer on this question is my own; I had forgotten it.)
First, let's write a "check for case conflict" function. This is just a matter of sorting with case-folding (so that "helloworld" and "helloWorld" are placed adjacent to each other), then using uniq -di to print any duplicate (after case-folding) strings, but no non-duplicates:
sort -f | uniq -di
If this produces any output, these are the "bad names". Let's capture the output in a temporary file and check its size, so we can print them to standard output as well:
#! /bin/sh
TF=$(mktemp)
trap "rm -f $TF" 0 1 2 3 15
checkstdin() {
sort -f | uniq -di > $TF
test -s $TF || return 0 # if $TF is empty, we are good
echo "non-unique (after case folding) names found!" 1>&2
cat $TF 1>&2
return 1
}
Now we just need to use it on files that will be committed, and perhaps on branch names as well. The former are listed with git ls-files, so:
git ls-files | checkstdin || {
echo "ERROR - file name collision, stopping commit" 1>&2
exit 1
}
You can fancy this up to use git diff-index --cached -r --name-only --diff-filter=A HEAD to check only added files, allowing existing case collisions to continue, and/or try to check things across many branches and/or commits, but that gets difficult.
Combine the above two fragments into one script (and test) and then simply copy it to an executable file named .git/hooks/pre-commit.
Checking branch names is a bit trickier. This really should happen when you create the branch name, rather than when you commit to it, and it's impossible to do a really good job on the client—it has to be done on a centralized server that has a proper global view.
Here is a way to do it on the server in a pre-receive script, in shell script rather than in Python (as in the linked answer). We still need the checkstdin function though, and you might want to do it in an update hook rather than a pre-receive hook, since you don't need to reject the entire push, just the one branch name.
NULLSHA=0000000000000000000000000000000000000000 # 40 0s
# Verify that the given branch name $1 is unique,
# even IF we fold all existing branch names' cases.
# To be used on any proposed branch creation (we won't
# look at existing branches).
check_new_branch_name() {
(echo "$1"; git for-each-ref --format='%(refname:short)' refs/heads) |
checkstdin || {
echo "ERROR: new branch name $1 is not unique after case-folding" 1>&2
exit 1 # or set overall failure status
}
}
while read oldsha newsha refname; do
... any other checks ...
case $oldsha,$refname in
$NULLSHA,refs/heads/*) check_new_branch_name ${refname#refs/heads/};;
esac
... continue with any other checks ...
done

How to get proper diff of merge commit in tig

if i got into tig main view, i get a nice graph of commits and merges. i'd prefer to just look at the merge commits to trunk but unlike with normal commits tig where tig shows the full diff with file contents, on merge commits it just shows a list of changed files in the diff view. How do i get tig to display the file contents diff on merge commits?
commit fb56223ec50cf659a308b3c9979c912881147689
Refs: [master], {origin/master}, {origin/HEAD}, juju-1.21-alpha1-229-gfb56223
Merge: 7e7c95d a017b5a
Author: Juju bot
AuthorDate: Mon Sep 22 01:22:03 2014 +0100
Commit: Juju bot
CommitDate: Mon Sep 22 01:22:03 2014 +0100
Merge pull request #803 from mjs/check-ssh-api-methods-are-allowed-during-upgrade
cmd/juju: ensure that API calls used by "juju ssh" are allowed during upgrades
We recently had a regression where an API call required by "juju ssh" wasn't being allowed by the API server while upgrades are in progress. "juju ssh" is one of the few commands that is supposed to work during upgrades.
The Client used by "juju ssh" is now forced into an interface and this is checked using reflection against what the API server will allow during upgrades. Effectively, the compiler helps to check that the required API methods will be allowed.
http://reviews.vapour.ws/r/64/diff/
apiserver/upgrading_root.go | 20 +++++++++++---------
cmd/juju/ssh.go | 15 +++++++++++----
cmd/juju/ssh_test.go | 24 ++++++++++++++++++++++++
3 files changed, 46 insertions(+), 13 deletions(-)
navigating to the individual files (j/k) in the view, says press 'Enter' to view file diff, but hitting enter gets "Failed to find file diff" err message. ideally i'd just be looking at the combined diff for the merge commit.
[update] i traced through tig with sysdig and it looks like its doing the following which on merge commits won't show the actual diff.
git show --encoding=UTF-8 --pretty=fuller --root --patch-with-stat --show-notes --no-color fb56223ec50cf659a308b3c9979c912881147689 --
i guess what i'm looking for on merge commits then is to parse the parents commits and then do something like the following
git diff 7e7c95d a017b5a
[update] so the diff actually isn't correct here as that diff would be between the two parents, and be more inclusive of changes then the merge itself, the best content rendering of the diff seems to be
git diff fb56223^ fb56223
Turns out this is pretty straightforward via external command integration.
I dropped this into ~/.tigrc:
bind diff 7 !git diff %(commit)^ %(commit)
and now just press 7 for the diff output i'm looking.
You have several options:
put this into your .tigrc
set diff-options = -m
you can set many options in ~/.tigrc, see also the manpage:
man tigrc
or start tig with the option -m
tig -m
Options to tig are passed to the underlying git command. More Info about this also in the manpage:
man tig

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