gitpython and git diff

Question

I am looking to get only the diff of a file changed from a git repo. Right now, I am using gitpython to actually get the commit objects and the files of git changes, but I want

Answer 1

You can use GitPython with the git command "diff", just need to use the "tree" object of each commit or the branch for that you want to see the diffs, for example:

repo = Repo('/git/repository')
t = repo.head.commit.tree
repo.git.diff(t)

This will print "all" the diffs for all files included in this commit, so if you want each one you must iterate over them.

With the actual branch it's:

repo.git.diff('HEAD~1')

Hope this help, regards.

Answer 2

I am not sure if you got what you were looking for!

Here is how you do it

import git
repo = git.Repo("path/of/repo/")

# the below gives us all commits
repo.commits()

# take the first and last commit

a_commit = repo.commits()[0]
b_commit = repo.commits()[1]

# now get the diff
repo.diff(a_commit,b_commit)

Cheers.

Answer 3

If you want to access the contents of the diff, try this:

repo = git.Repo(repo_root.as_posix())
commit_dev = repo.commit("dev")
commit_origin_dev = repo.commit("origin/dev")
diff_index = commit_origin_dev.diff(commit_dev)

for diff_item in diff_index.iter_change_type('M'):
    print("A blob:\n{}".format(diff_item.a_blob.data_stream.read().decode('utf-8')))
    print("B blob:\n{}".format(diff_item.b_blob.data_stream.read().decode('utf-8'))) 

This will print the contents of each file.

Answer 4

I'd suggest you to use PyDriller instead (it uses GitPython internally). Much easier to use:

for commit in RepositoryMining("path_to_repo").traverse_commits():
    for modified_file in commit.modifications: # here you have the list of modified files
        print(modified_file.diff)
        # etc...

You can also analyze a single commit by doing:

for commit in RepositoryMining("path_to_repo", single="123213")

Answer 5

Git does not store the diffs, as you have noticed. Given two blobs (before and after a change), you can use Python's difflib module to compare the data.

Answer 6

If you want to do git diff on a file between two commits this is the way to do it:

import git

repo = git.Repo()
path_to_a_file = "diff_this_file_across_commits.txt"

commits_touching_path = list(repo.iter_commits(paths=path))

print repo.git.diff(commits_touching_path[0], commits_touching_path[1], path_to_a_file)

This will show you the differences between two latest commits that were done to the file you specify.

Hope this helped.