GenAI Git Commits

Generating a git commit message is quickly become a classic GenAI application for developers.

To help with this, we will craft a GenAIScript script.

The script acts as a regular node.js automation script and uses runPrompt
to issue calls to the LLM and ask the user to confirm the generated text.

🔍 Explaining the Script

We start by using git check if there are any staged changes in the Git repository:

let { stdout } = await host.exec("git", ["diff", "--cached"])

If no changes are staged, we ask the user if they want to stage all changes. If the user confirms, we stage all changes. Otherwise, we bail out.

    const stage = await host.confirm("Stage all changes?", {
        default: true,
    })
    if (stage) {
        await host.exec("git", ["add", "."])
        stdout = (await host.exec("git", ["diff", "--cached"])).stdout
    }
    if (!stdout) cancel("no staged changes")

We generate an initial commit message using the staged changes:

message = (
    await runPrompt(
        (_) => {
            _.def("GIT_DIFF", stdout, { maxTokens: 20000 })
            _.$`GIT_DIFF is a diff of all staged changes, coming from the command:
\`\`\`
git diff --cached
\`\`\`
Please generate a concise, one-line commit message for these changes.
- do NOT add quotes`
        },
        { temperature: 0.8 }
    )
).text

The prompt configuration above indicates that the message should be concise,
related to the "git diff --cached" output, and should not include quotes.

User chooses how to proceed with the generated message:

    choice = await host.select(
        message, [
            { name: "commit", value: "commit", description: "accept message and commit" },
            ...
        ])

Options are given to edit or regenerate the message. If the user chooses to edit the message, we ask them to input a new message:

    if (choice === "edit") {
        message = await host.input("Edit commit message", {
            required: true,
        })
        choice = "commit"
    }

If the user chooses to commit the message, we commit the changes:

    if (choice === "commit" && message) {
        console.log((await host.exec("git", ["commit", "-m", message])).stdout)
    }

🚀 Running the Script

You can run this script using the CLI.

genaiscript run gcm

If you are using npx,

npx --yes genaiscript run gcm

This command will run the script, and guide you through the process of generating and committing a Git message using AI, making your commits more informative and consistent.

You can wrap this command in a gcm.sh file or in your package script section in package.json:

{
    "devDependencies": {
        "genaiscript": "..."
    },
    "scripts": {
        "gcm": "genaiscript run gcm"
    }
}

Then you can run the script using:

npm run gcm

Acknowledgements

This script was inspired from Karpathy's commit message generator.