Pylint with pre-commit and EsLlint with husky

Question

I have a project with a frontend in JS and backend in Python. Frontend had been configured with husky pre-commit hook. Today I've configured Pylint with pre-commit library but husky hooks had been overwritten by that move. Is it possible to combine pre-commit and husky libraries? If not... what's the best way to solve the problem?

Fairish

Answer 1

pre-commit has a "migration mode" for running other existing hook frameworks. It seems that husky is slightly too clever in their hook implementation for detecting what hook you're running -- they base it on the filename that's being executed

the way pre-commit's migration mode works is it takes any existing hook script (in this case, the hook script written by husky to .git/hooks/pre-commit) and adds the extension .legacy. then during execution it runs that script.

but to husky, it looks like the pre-commit.legacy hook is running (!)

a little hack is to define pre-commit.legacy in package.json which seems to work:

package.json

{
  "husky": {
    "hooks": {
      "pre-commit.legacy": "echo hello world"
    }
  },
  "dependencies": {
    "husky": "^4.3.0"
  }
}

.pre-commit-config.yaml

# See https://pre-commit.com for more information
# See https://pre-commit.com/hooks.html for more hooks
repos:
-   repo: https://github.com/pre-commit/pre-commit-hooks
    rev: v3.2.0
    hooks:
    -   id: trailing-whitespace
    -   id: end-of-file-fixer
    -   id: check-yaml
    -   id: check-added-large-files
$ git commit -m "both"
husky > pre-commit.legacy (node v12.18.3)
hello world
Trim Trailing Whitespace.................................................Passed
Fix End of Files.........................................................Passed
Check Yaml...........................................(no files to check)Skipped
Check for added large files..............................................Passed
[master 7bd8807] both
 1 file changed, 1 insertion(+), 1 deletion(-)

that said, this seems fragile. pre-commit is designed to support many different programming languages (even though it is written in python, it has native support for 10+ programming languages (including javascript))

---

A first place replacement might be to just call husky from a local pre-commit hook:

package.json

{
  "husky": {
    "hooks": {
      "pre-commit": "echo hello world"
    }
  },
  "dependencies": {
    "husky": "^4.3.0"
  }
}

.pre-commit-config.yaml

# See https://pre-commit.com for more information
# See https://pre-commit.com/hooks.html for more hooks
repos:
-   repo: https://github.com/pre-commit/pre-commit-hooks
    rev: v3.2.0
    hooks:
    -   id: trailing-whitespace
    -   id: end-of-file-fixer
    -   id: check-yaml
    -   id: check-added-large-files
-   repo: local
    hooks:
    -   id: husky-run-pre-commit
        name: husky
        language: system
        entry: node_modules/.bin/husky-run pre-commit
        pass_filenames: false
        always_run: true

execution

$ pre-commit run --all-files --verbose
Trim Trailing Whitespace.................................................Passed
- hook id: trailing-whitespace
- duration: 0.03s
Fix End of Files.........................................................Passed
- hook id: end-of-file-fixer
- duration: 0.03s
Check Yaml...............................................................Passed
- hook id: check-yaml
- duration: 0.05s
Check for added large files..............................................Passed
- hook id: check-added-large-files
- duration: 0.05s
husky....................................................................Passed
- hook id: husky-run-pre-commit
- duration: 0.07s

husky > pre-commit (node v12.18.3)
hello world

this solution however doesn't take advantage of pre-commit's js support, it just invokes the already-existing husky hooks

---

a more native solution would be to install js hooks directly with pre-commit, for example if you're using eslint:

repos:
-   repo: https://github.com/pre-commit/mirrors-eslint
    rev: 'v7.9.0'  # Use the sha / tag you want to point at
    hooks:
    -   id: eslint

$ pre-commit  run --all-files
[INFO] Initializing environment for https://github.com/pre-commit/mirrors-eslint.
[INFO] Initializing environment for https://github.com/pre-commit/mirrors-eslint:[email protected].
[INFO] Installing environment for https://github.com/pre-commit/mirrors-eslint.
[INFO] Once installed this environment will be reused.
[INFO] This may take a few minutes...
eslint...................................................................Passed

---

disclaimer: I am the author of pre-commit

Vina

hehe :)) Thank you for very useful and comprehensive answer. I've tried to install eslint directly via pre-commit but it was complaining weirdly... smth like Configuration for rule "react/jsx-boolean-value" is invalid... That's why I've decided to take an old-good duck tape from the shelf :D – Fairish

ah you probably want to include your plugins – Vina

How can I get the native solution (3rd option) to run a command from the package.json? In husky I run lint and lint:fix to autocorrect linting issues when you check in. Also does the native solution use the project's .eslintrc.json for linting? – Hobbledehoy

Answer 2

A solution that works better for me, with the latest version of pre-commit (2.14.0) and husky (7.0.2) is to integrate pre-commit into husky, rather than the other way around.

In the ./husky/_/pre-commit file, I added pre-commit run.

See below:

#!/bin/sh
. "$(dirname "$0")/_/husky.sh"

npx lint-staged
npx pretty-quick --staged
pre-commit run

Juvenilia