A Python script to compute "true" code churn of a Git repository. Useful for software teams to openly help manage technical debt.
Code churn has several definitions, the one that to me provides the most value as a metric is:
"Code churn is when an engineer rewrites their own code in a short period of time."
Reference: https://www.pluralsight.com/blog/teams/why-code-churn-matters
Solutions that I've found online looked at changes to files irrespective whether these are new changes or edits to existing lines of code (LOC) within existing files. Hence this solution that segments line-of-code edits (churn) with new code changes (contribution).
Tested with Python version 3.5.3 and Git version 2.20.1
This lightweight script looks at commits per author for a given date range on the current branch. For each commit it bookkeeps the files that were changed along with the LOC for each file. LOC are kept in a sparse structure and changes per LOC are taken into account as the program loops. When a change to the same LOC is detected it updates this separately to bookkeep the true code churn. Result is a print with aggregated contribution and churn per author for a given period in time.
Note: This includes the --no-merges flag as it assumes that merge commits with or without merge conflicts are not indicative of churn.
- after after a certain date, in YYYY[-MM[-DD]] format
- before before a certain date, in YYYY[-MM[-DD]] format
- author author string (not a committer), leave blank to scope all authors
- dir include Git repository directory
- -h, --h, --help show this help message and exit
- -exdir exclude Git repository subdirectory -- --show-file-data display line count changes per file
python ./gitcodechurn.py after="2018-11-29" before="2019-03-01" author="an author" dir="/Users/myname/myrepo" -exdir="excluded-directory"author: an author
contribution: 844
churn: -28python ./gitcodechurn.py after="2018-11-29" before="2019-03-01" author="" dir="/Users/myname/myrepo" -exdir="excluded-directory"authors: author1, author2, author3
contribution: 4423
churn: -543python ./gitcodechurn.py after="2018-11-29" before="2021-11-05" author="flacle" dir="/Users/myname/myrepo" --show-file-dataauthor: flacle
contribution: 337
churn: -19
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FILE NAME | LINE # | ADDED | REMOVED
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gitcodechurn.py | 1 | 190 | 0
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gitcodechurn.py | 2 | 4 | 0
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gitcodechurn.py | 37 | 2 | 0
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gitcodechurn.py | 40 | 0 | 1
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gitcodechurn.py | 42 | 1 | 0
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gitcodechurn.py | 45 | 0 | 1
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gitcodechurn.py | 47 | 1 | 0
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gitcodechurn.py | 50 | 0 | 1
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gitcodechurn.py | 52 | 1 | 0
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gitcodechurn.py | 55 | 0 | 1
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gitcodechurn.py | 57 | 8 | 1
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gitcodechurn.py | 66 | 2 | 0
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gitcodechurn.py | 62 | 0 | 1
...
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gitcodechurn.py | 200 | 1 | 0
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README.md | 12 | 2 | 0
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README.md | 16 | 0 | 1
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README.md | 18 | 1 | 0
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README.md | 21 | 11 | 0
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README.md | 20 | 0 | 1
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README.md | 33 | 1 | 0
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README.md | 22 | 0 | 1
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README.md | 35 | 1 | 0
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README.md | 24 | 0 | 2
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README.md | 37 | 3 | 0
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README.md | 41 | 12 | 0 Outputs of Usage Example 1 can be used as part of a pipeline that generates bar charts for reports:
At this time, the code is organized into a script which can be located at gitcodechurn.py. There is an open issue to conver this repository
into a more formal Object Oriented structure.
For now the code is located in gitcodechurn.py and the tests are located in test_gitcodechurn.py. To test, kindly ensure pytest and pytest-mock are installed. Then, in project root run
pytest