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I am trying to bump the version of my package.json file when I commit, but only if the commit message is prefixed correctly: MJ prefix triggers a patch bump, ^ prefix triggers a minor bump. I wrote a gulp task to do this and it works, the only problem is that I can't get the message of the current commit, execute the task, then add package.json to the commit and continue.

I tried running my task on these two git hooks:

pre-commit

Problem:

  • I only have access the previous commit message in this hook, not the one we're doing right now.

What works

  • I can bump the version, but only based on the previous commit message
  • I can stage package.json
  • package.json can then be added to the commit along with the rest

prepare-commit-msg

Problem:

  • staging package.json does not add it to the commit

What works

  • I can bump the version based on the current commit message
  • I can stage package.json

This is my gulp task that I've tried with the two hooks. I removed some noise to try to keep it minimal. 

import * as fs from "fs";
import gulp from "gulp";
import * as shell from "shelljs";
import pkg from "./package.json";

const getCommitMsg = () => fs.readFileSync(".git/COMMIT_EDITMSG", "utf8");
gulp.task(
    BUMP_VERSION.task,
        (done) => {

            const message = getCommitMsg();
            const isMinor = message.startsWith(MINOR_PREFIX);
            const isPatch = message.startsWith(PATCH_PREFIX);

            if (!isMinor && !isPatch) {
                done();
                return exit(EC.NOT_VERSION);
            }

            const newPatch = isPatch ? parseInt(patch) + 1 : 0;
            const newMinor = isMinor ? parseInt(minor) + 1 : minor;

            const newVersion = `${major}.${newMinor}.${newPatch}`;
            const newPkg = Object.assign({}, pkg, { version: newVersion }); // update version
            fs.writeFileSync("./package.json", JSON.stringify(newPkg, null, 4));

            shell.exec("git add ./package.json");

            done();
        },
);

Pretty much everything relies on the commit message, which is fetched using the getCommitMsg function. Maybe fs.readFileSync(".git/COMMIT_EDITMSG", "utf8"); isn't the way to go? Perhaps there is another command I could run (with shelljs) to get the current commit message in the pre-commit hook? Otherwise if I use the prepare-commit-msg hook, then I can get the correct message, but then how would I add it to the current commit along with the other staged files?

MaxiJonson
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1 Answers1

3

You can use the commit-msg hook to read the commit message, take actions based on that, stage files and commit

.git/hooks/commit-msg

COMMIT_MSG_FILE=$1

node bump.js
git add package.json
git commit -m "`cat $COMMIT_MSG_FILE`" --no-verify
false

node bump.js will increment the version in package.json (similar to your gulp task)

git add package.json will stage the modified file

git commit -m "cat $COMMIT_MSG_FILE" --no-verify will commit the staged files but skipping the hooks (pre-commit and commit-msg)

false will stop the original commit since we've already committed in the last line

duggi
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  • This doesn't solve my specific problem but that is my fault for leaving off some info. Your answer pretty much solves the question though! I just forgot to mention I also have a post-commit hook that switches branches and cherry-picks the commit into that branch. But you have given me something to work off! Before your answer, I also found a pretty slow solution: put the bump task into the post-commit hook instead and make a commit for only the package.json. It's not pretty but it got the job done. Anyways, thanks for your answer! I'm sure it'll help someone with a similar problem! :) – MaxiJonson Mar 30 '19 at 03:45
  • for anyone interested in how to gracefully do what's described here, you can check out [Can a Git hook automatically add files to the commit?](https://stackoverflow.com/a/12802592/10429793) It's very similar however instead of stopping the original commit to create it's own, it modifies it in the post-commit script – Krzysztof Krzeszewski Sep 08 '20 at 09:08