How to enforce a "no spaces in filenames" policy in git?

Question

As the title says. I want git to refuse to add files which contain spaces in filenames. Is there a config which enforces this?

Answer 1

The regular expression of **\ ** can be used in the .gitignore file for rejecting file names with spaces.

Here is the demonstration of a working example:

Step 1: Add **\ ** to .gitignore file in the repository

$ my-repository (master)
$ ls
core/  it.tests/  pom.xml  README.md  ui.apps/  ui.content/

$ cat .gitignore
**/.classpath
**/target
**/node_modules/
/node_modules/
/build/

**\ ** 

          ---> Ignore file that has blank spaces in the name

---

Step 2: Create a file with blank spaces in the name (Example: x y z.txt)

$ echo "Hello! How are you doing?" > "x y z.txt"

$ ls
 core/   it.tests/   pom.xml   README.md   ui.apps/   ui.content/

 'x y z.txt'

---

Step 3: Try to add the file with spaces in name to the repository and commit

$ git add .

$ git commit -a

On branch master
Your branch is up to date with 'origin/master'.

nothing to commit, working tree clean

---

Result:

The pattern of **\ ** in .gitignore file prevents the file with blank space in its name from being added to the repository.

More information on .gitignore file:

https://git-scm.com/docs/gitignore

Answer 2

I want git to refuse to add files which contain spaces in filenames.

What you are asking, effectively, is how to prevent certain files from being added to the index. What you specifically request is not currently possible using Git hooks.

Perhaps you would like to request a pre-add hook? This seems reasonable to me, and you are not the first to ask for it. I recommend engaging with the Git community to discuss further.

Near-term / priorities

Now, if you want to solve your problem in the near-term, I suggest we step back. Is one of the following goals important than the other?

Preventing a file from being ...

1. ... added to the index? (git add)

2. ... committed to the repository? (git commit)

Refuse to commit

From what I can tell, blocking a commit is the core requirement here.

So, going forward, this answer interprets the question as: "I want git to refuse to commit files which contain spaces in filenames.

I see two families of answers: (a) the commonly-used answers and (b) less-common answers

Commonly-used: pre-commit hooks

Practically, I recommend using a Git pre-commit hook:

The pre-commit hook is run first, before you even type in a commit message. It’s used to inspect the snapshot that’s about to be committed, to see if you’ve forgotten something, to make sure tests run, or to examine whatever you need to inspect in the code. Exiting non-zero from this hook aborts the commit, although you can bypass it with git commit --no-verify. You can do things like check for code style (run lint or something equivalent), check for trailing whitespace (the default hook does exactly this), or check for appropriate documentation on new methods.

I see two approaches:

1. shell (no additional dependencies): The open source GitHooks documentation has an example pre-commit shell script.

2. a framework: I recommend pre-commit. (This is not included with git.)

pre-commit: A framework for managing and maintaining multi-language pre-commit hooks

Why was the pre-commit framework created?

As we created more libraries and projects we recognized that sharing our pre-commit hooks across projects is painful. We copied and pasted unwieldy bash scripts from project to project and had to manually change the hooks to work for different project structures.

Less-common approaches

1. If you have control over the environment, you might consider writing your own wrapper on top of git add.

2. See How to automatically invoke a script before a git add? for discussions of (a) smudge and clean; (b) git-gulp; (c) possibly others that get added over time.

Why .gitignore will not work cannot prevent commits

Updates: I added strikethrough text to indicate where I was wrong in my previous edits. Corrections and changes are called out in bold italics.

• A .gitignore file does not prevent files from being committed; rather, it prevents untracked files from being tracked.

• git add file.txt will always succeed in adding file.txt to the index, regardless of the the contents of .gitignore

• Correction: git add file.txt will warn if file.txt matches a pattern in .gitignore

• Clarification: git add -f file.txt will always succeed in adding file.txt to the index, regardless of the the contents of .gitignore

• Addition: Because of the git add -f command, you can see that .gitignore can only warn, not prevent, files from being added to the index (aka staged). Once a file is staged, it is trivial to commit. Therefore, in the context of this answer, where the goal is to prevent commits (see above), .gitignore is not adequate.

• Once a file is tracked, it can be committed staged with git commit file.txt -- regardless of .gitignore.

• To elaborate: Once a file is tracked, it can be be staged with git add file.txt and committed with git commit -- regardless of .gitignore.