Is None possible for the attribute change_type of git.diff.Diff object?

[jiseongg]

I am using GitPython 3.1.37 to use commit history for software analysis.
While using git.diff.Diff instance, I accidentally found that the change_type attribute was None, which I had expected to be one of ('A', 'C', 'D', 'R', 'M', 'T').

I am not sure this is bug. If not, I want to know when it happens.

The sample code to reproduce my situation is like follows:

from git import Repo

# used repository: https://github.com/gocd/gocd
repo = Repo('/path/to/repository')

prev_commit = repo.commit('86064ef5ee28e0d0d12911f46fd603d15246fdd5')
next_commit = repo.commit('42e58c22aefd036b6fdd2095ed0d391f5238c6c4')

diff_index = prev_commit.diff(next_commit, create_patch=True)

# one example file
target_diff = list(filter(
    lambda d: d.a_path == 'agent-bootstrapper/src/com/thoughtworks/go/agent/bootstrapper/osx/MacAboutBox.java',
    diff_index))[0]

print(target_diff.change_type) # `None` printed

The result of actual git diff command, which considers the aforementioned diff as 'M' type:

# git diff 86064ef5ee28e0d0d12911f46fd603d15246fdd5 42e58c22aefd036b6fdd2095ed0d391f5238c6c4 --diff-filter 'M' -- agent-bootstrapper/src/com/thoughtworks/go/agent/bootstrapper/osx/MacAboutBox.java

diff --git a/agent-bootstrapper/src/com/thoughtworks/go/agent/bootstrapper/osx/MacAboutBox.java b/agent-bootstrapper/src/com/thoughtworks/go/agent/bootstrapper/osx/MacAboutBox.java
index 0103494d4a..90d876badb 100644
--- a/agent-bootstrapper/src/com/thoughtworks/go/agent/bootstrapper/osx/MacAboutBox.java
+++ b/agent-bootstrapper/src/com/thoughtworks/go/agent/bootstrapper/osx/MacAboutBox.java
@@ -55,7 +55,7 @@ public class MacAboutBox extends JFrame implements ActionListener {
         aboutLabels.add(bodyLabel("Bootstrapper Version " + getBootstrapperVersion()));
         aboutLabels.add(emptyLabel());
         aboutLabels.add(bodyLabel("Java Version " + System.getProperty("java.version")));
-        aboutLabels.add(bodyLabel("Copyright (C) 2013 ThoughtWorks Inc."));
+        aboutLabels.add(bodyLabel("Copyright (C) 2015 ThoughtWorks Inc."));
         aboutLabels.add(emptyLabel());

         Panel textPanel2 = new Panel(new GridLayout(aboutLabels.size(), 1));

Thank you for any help you can offer.

[Byron]

I looks like change_type is known to possibly be None as per the bolted on type-system. Ideally the editor would know and warn about it, but apparently this didn't happen here.

The actual problem seems to be though that a modified file isn't classified as such - instead, no classification is provided.

Since I don't know why that is, a contributor could probably create a test with reproduction and fix it that way, or at least, understand what's going on.

---

Instead of trying to fix this, I recommend using gitoxide - it will probably be multiple times faster and doesn't have these typing problems either.

[jiseongg]

Thank you for the recommendation!! I will try to use gitoxide :)