Common Pre-Commit Errors and How to Solve Them

Having issues with your pre-commit setup? In this troubleshooting guide, I've collected the most common errors pre-commit users face and provided explanations and guidance for fixing them. If you are new to pre-commit or would like a refresher, I would recommend you start with my How to Set Up Pre-Commit Hooks article.

Pick an issue to troubleshoot

Issues running pre-commit:

• pre-commit: command not found / command not found: pre-commit
• `pre-commit` not found. did you forget to activate your virtualenv?

Issues with .pre-commit-config.yaml:

• .pre-commit-config.yaml is not a file
• [ERROR] Your pre-commit configuration is unstaged
• InvalidConfigError

Issues with .pre-commit-hooks.yaml:

• .pre-commit-hooks.yaml is not a file
• InvalidManifestError

pre-commit: command not found / command not found: pre-commit

You are most likely seeing this because you (or some process) attempted to run pre-commit on the command line and got something like this as your error message:

pre-commit run
zsh: command not found: pre-commit

The fix

If you already installed the pre-commit package, you probably need to activate the virtual environment in which you installed, as the pre-commit executable gets created after you install the package.

If you haven't installed pre-commit at all, then I suggest you start from my How to Set Up Pre-Commit Hooks article.

`pre-commit` not found. did you forget to activate your virtualenv?

If you are seeing this error, it means that at some point you successfully installed pre-commit hooks in your repository, and pre-commit is registered with Git's hooks system, but the script registered with Git is not able to run pre-commit as a Python module (with -m) and also cannot find the pre-commit executable.

The fix

Assuming you did not uninstall pre-commit, you should follow the suggestion and activate your virtual environment. However, if you did uninstall it or just want a refresher on how to set it up properly, check out my How to Set Up Pre-Commit Hooks article.

.pre-commit-config.yaml is not a file

This means that pre-commit was unable to find a .pre-commit-config.yaml file in your repository.

The fix

If you did create a configuration file, make sure you didn't make a typo with the filename and that it is at the root of your repository. Note that you are free to call the file whatever your wish; however, pre-commit will only find it automatically when you name it .pre-commit-config.yaml. If you want to use a different name, you will need to pass --config <your-file> when you install, run, or use any other pre-commit subcommand that needs a configuration file.

If you did not create a configuration file, I suggest you start from my How to Set Up Pre-Commit Hooks article.

[ERROR] Your pre-commit configuration is unstaged

This means that you changed your .pre-commit-config.yaml file since your last commit and pre-commit isn't sure which configuration you actually want to use: the original one or the one you are considering but haven't committed to yet.

[ERROR] Your pre-commit configuration is unstaged.
`git add .pre-commit-config.yaml` to fix this.

The fix

If you do want to use your updates, stage your changes to the configuration:

git add .pre-commit-config.yaml

If not, undo the changes:

git restore .pre-commit-config.yaml

If you don't want to undo the changes, you can also stash them for later.

InvalidConfigError

If you see an error that looks like this, your .pre-commit-config.yaml file is malformed. This could mean you have the wrong data types, missing keys, or that the YAML itself is invalid as shown here:

An error has occurred: InvalidConfigError:
==> File .pre-commit-config.yaml
=====> while parsing a block mapping
  in "<unicode string>", line 1, column 1
did not find expected key
  in "<unicode string>", line 46, column 1
Check the log at /Users/stefanie/.cache/pre-commit/pre-commit.log

The fix

Open up your .pre-commit-config.yaml file, and make sure all the indentation is correct – this is most often the problem. You can run the following to check whether you fixed the issue (take note of the line number – in this example, the file's incorrect indentation is at line 46):

pre-commit validate-config .pre-commit-config.yaml

=====> while parsing a block mapping
  in "<unicode string>", line 1, column 1
did not find expected key
  in "<unicode string>", line 46, column 1
Check the log at /Users/stefanie/.cache/pre-commit/pre-commit.log

Be sure to read the error messages for the specifics of what needs to be fixed in your file as you may have invalid keys or data types to fix as well.

.pre-commit-hooks.yaml is not a file

This means that pre-commit was unable to find a .pre-commit-hooks.yaml file in one of the repositories you are attempting to use hooks from.

The fix

If you are trying to create your own hook, make sure you have committed a .pre-commit-hooks.yaml file to the repository, and be sure to check out my How to Create a Pre-Commit Hook article for a complete walkthrough of the process.

If you are using a hook from someone else, make sure the repository actually supports usage with pre-commit: if the .pre-commit-hooks.yaml file does not exist in the top-level of the repository, they do not support it.

InvalidManifestError

If you see an error that looks like this, your .pre-commit-hooks.yaml file is malformed. This could mean that the file isn't proper YAML, has the wrong data types, or is missing required keys as shown here:

An error has occurred: InvalidManifestError:
==> File /var/folders/.../.pre-commit-hooks.yaml
==> At Hook(id='strip-exif')
=====> Missing required key: language
Check the log at /Users/stefanie/.cache/pre-commit/pre-commit.log

The fix

Open up your .pre-commit-hooks.yaml file and address the issues mentioned in the error message (missing the language key here). You can run the following to check whether you fixed the issue:

pre-commit validate-manifest .pre-commit-hooks.yaml

==> File .pre-commit-hooks.yaml
==> At Hook(id='strip-exif')
=====> Missing required key: language

Note that, in addition to providing the missing required key (language), the error message includes the particular hook in .pre-commit-hooks.yaml where the error occurs (strip-exif).

Did you find this helpful or are you having an issue that isn't covered? Let me know in the comments below.