Since Git was designed for the mailing-list heavy workflow of the Linux kernel development community, it has commands that make it easy to transform a commit (also known as a patch) into an email and vice-versa. For example, git format-patch, git am, git send-email and git imap-send.

While git send-email can be used to send a list of patches prepared using git format-patch to a development mailing list via an SMTP server, git imap-send is designed to upload git format-patch-prepared patches to an IMAP folder, so that they can then be sent using a regular mail client (maybe after tweaking the cover letter or the in-patch commentaries).

Even if you want to keep up-to-date with the development mailing list of your favorite project, you might not want to subscribe to the mailing list, to avoid cluttering your inbox. After all, most development mailing list have a web interface which can be used to browse the list, such as https://lore.kernel.org/git/, the archive for the Git mailing list.

But if you're not subscribed to the mailing list, and see an interesting thread that you'd like to answer to, how can you do it easily ? If the web archive provides a way to download messages, you can import them into your favorite mail client, but that can be hard to automate when you are using a desktop email client (and not old-school mutt or alpine).

So why not use git imap-send ? That's the plan, but since it's designed to work hand-in-hand with git format-patch, it expects a certain ordering of email headers ("From: ", "Date :" and "Subject :" must appear in that order). So a simple

curl https://lore.kernel.org/git/<message-id>/raw | git imap-send

might work if the email corresponding to <message-id> is a patch created by git format-patch, but it probably won't work if it's a regular email (say, a bug report or user question that you wish to answer to).

To make git imap-send happy, we simply have to shuffle the email headers in the expected order before piping in the mbox. I use this little Python script that I name git-in to conveniently place it in the git namespace :

#!/usr/bin/env python3

import sys
import os
import mailbox
import urllib.request
import string
import random
import argparse
import gzip

# Parse input
parser = argparse.ArgumentParser(
           prog='git in', 
           description="download raw or gzip'ed mbox from given URL and print messages with headers reordered for `git imap-send`",
           epilog='example usage: git in <url> | git imap-send')
parser.add_argument("url", help="URL to download mbox from")
args = parser.parse_args()

# Construct file name
ext = '.mbox'
mbox = os.environ.get('TMPDIR') + 'git-in-' + ''.join(random.choices(string.ascii_lowercase, k=8)) + ext

# Check if the mbox is compressed with gzip
must_decompress = False
gz_ext = args.url[-3:]
if gz_ext == '.gz':
  must_decompress = True

# Download the mbox file from `url` and save it locally under `mbox`:
# https://stackoverflow.com/a/7244263/
with urllib.request.urlopen(args.url) as response, open(mbox, 'wb') as out_file:
    data = response.read() # a `bytes` object
    if must_decompress:
      out_file.write(gzip.decompress(data))
    else:
      out_file.write(data)

# Print messages with ordered headers
for message in mailbox.mbox(mbox):
    # Get 'From:', 'Date:' and 'Subject:' header values 
    from_header = message['from']
    date = message['date']
    subject = message['subject']
    # Delete the 3 headers
    del message['from']
    del message['date']
    del message['subject']
    # Write the 3 headers in the order `git imap-send` expects
    message['From'] = from_header
    message['Date'] = date
    message['Subject'] = subject
    # Print unixfrom and message
    print('From ' + message.get_from())
    print(message)
    
os.remove(mbox)

To upload an email or a collection of emails in a gzip'ed mbox to the IMAP inbox you configured for git imap-send, simply do :

git in https://lore.kernel.org/git/<message-id>/raw | git imap-send  # single email
git in https://lore.kernel.org/git/<message-id>/t.mbox.gz | git imap-send  # whole thread