Analyze programming language usage over time in a git repository and produce a graphical or textual representation of the result.

Available output file formats:

• .svg - Scalable Vector Graphics
• .png - Portable Network Graphics
• .csv - Comma-separated values
• .tsv - Tab-separated values

Showing the pace at which Kotlin is replacing Java in AndroidX support library by language usage percentage:

% cd ~/src/androidx
% git-repo-language-trends --relative --max-commits 30 --min-interval-days 60  .kt .java
% open androidx-language-trends.png

Showing how the implementation of CPython has grown over the last decades in terms of number of lines of C (.c and .h files) and Python (.py files):

% cd ~/src/cpython
% git-repo-language-trends --max-commits 30 --min-interval-days 365 .c+.h .py
% open cpython-language-trends.png

Showing the pace at which TypeScript is replacing JavaScript in mattermost-webapp by language usage percentage:

% cd ~/src/mattermost-webapp
% git-repo-language-trends --min-interval-days 30 --max-commits 25 --relative .ts+.tsx .js+.jsx
% open mattermost-webapp-language-trends.png

Showing line count trends for Swift, Objective-C (.m and .h files summed together), and Markdown (.md) in the iOS Charts library:

% cd ~/src/Charts
% git-repo-language-trends  --min-interval-days 60 .swift .m+.h .md
% open Charts-language-trends.png

Same data as above, but as a comma-separated values (.csv) file, in case you want to generate plots yourself from the raw data, and limited to 10 commits:

% cd ~/src/Charts
% git-repo-language-trends  --max-commits 10 --min-interval-days 60 .swift .m+.h .md -o charts-language-trends.csv
% cat charts-language-trends.csv
        ,.swift,.m+.h,.md
2019-03-20,32163,6205,3785
2019-06-10,32347,6205,3859
2019-09-09,32368,6205,3859
2019-11-13,32746,6205,4007
2020-02-13,32687,6205,4015
2020-04-16,32778,6205,891
2020-07-08,32781,6205,897
2020-10-08,32785,6205,4215
2020-12-15,32176,6219,4225
2021-02-26,31771,6219,4252

# Install the tool to ~/opt/git-repo-language-trends/bin/git-repo-language-trends
python3 -m venv ~/opt/git-repo-language-trends
~/opt/git-repo-language-trends/bin/pip install git-repo-language-trends

For brevity ~/opt/git-repo-language-trends/bin/git-repo-language-trends is shortented to git-repo-language-trends below.

First go to the git repository for a project.

cd ~/src/your-project

Then run the tool, passing the file extensions for the languages you are interested in as positional arguments:

git-repo-language-trends .java .kt

For languages with multiple file extensions such as C, you can use the + syntax which will automatically summarize line counts from both file extensions. To compare C and Rust:

git-repo-language-trends .c+.h .rs

If you want relative numbers, enable the --relative option:

git-repo-language-trends --relative .c+.h .rs

Use git-repo-language-trends --help to see more options.

If git-repo-language-trends is not in your PATH after installation you can run the tool via its module, e.g.:

python3 -m git_repo_language_trends --help

Programming langauge usage is determined by the total number of newline characters in files with a given file extension.

It is easy to come up with something more fancy, but it would be overkill.

This program is pretty fast, because it uses the pygit2 wrapper for the C library libgit2. It easily counts hundreds of thousands lines per second on low-end machines. It also uses a cache keyed by git blob ID to avoid counting lines for the same blob twice.

Clone this repo:

git clone https://github.com/Enselic/git-repo-language-trends.git

Create a venv:

python3 -m venv ~/venv-grlt
source ~/venv-grlt/bin/activate

Install and update dev dependencies:

python3 -m pip install --upgrade pip flake8 pytest

Make an editable install:

python3 -m pip install -e .

then make your changes. When done, lint and test:

flake8 && pytest -vv