The rationale: If you move code snippets via chat, Stackoverflow, markdown files, Gists or PRs or if your team work on a mix of Windows, Mac and Linux machines or if your team use a mix of various code editors and IDEs then indenting with spaces is the only way to guarantee the code aligns consistently wherever it goes.
The trap: If you are actively maintaining or porting from a legacy codebase with a mix of tab and space-indented lines it is far too easy to accidentally author tab-indented lines. IDEs have some great settings to help but they will never be a strict gate-keeper.
My solution: A pre-commit hook that simply does not pass tab-indented code. It only checks new lines of code and if it finds a tab-indented one, it aborts the commit and reports which lines need to be corrected.
Simply copy the pre-commit file into your repository's githooks folder (usually .git/hooks/) and give it execute permissions. Now it will be invoked on every commit.
# From the root folder of your repo...
cd .git/hooks
If you have wget installed...
wget https://raw.githubusercontent.com/martinjoiner/pre-commit-hook-no-tab-indented-lines/main/pre-commit .
If no wget, try cURL instead...
curl https://raw.githubusercontent.com/martinjoiner/pre-commit-hook-no-tab-indented-lines/main/pre-commit -o pre-commit
Give the file execute permissions
chmod +x pre-commit
cd ../../
To learn more about githooks visit https://git-scm.com/docs/githooks