Unit-e clonemachine

This python script applies basic transformations to the Bitcoin Core codebase:

• replaces bitcoin with unit-e (in various variations)
• replaces names of units like COIN → UNIT and CENT → EEES
• renames files
• changes the name of the client from Satoshi to Feuerland
• fixes tests accordingly
• etc.

Purpose

The idea is to apply this script every time we rebase against/merge with the Bitcoin Core repository. This way we can have things renamed nicely and save ourselves a lot of merge headaches.

Workflow

We work on our fork of bitcoin. Whenever we want to merge with bitcoin upstream we fork the bitcoin branch we want to merge with again and apply the clonemachine one it. Then we merge with that adjusted fork.

# do not blindly copy n paste, this outlines the procedure
git remote add bitcoin [email protected]:bitcoin/bitcoin.git
git fetch bitcoin
git checkout -b bitcoin-integration bitcoin/master
<path>/<to>/<clonemachine>/clonemachine.py fork --unit-e-branch=master
git merge master

Clonemachine has a list of appropriated files, i.e. files which have changed so much in unit-e that it doesn't make sense to try to merge them. They are replaced by the version from the unit-e repository. You need to pass the branch where the unit-e code is with the --unit-e-branch option.

You can see the changes of all appropriated files since the last merge by running clonemachine.py show-upstream-diff. You need to specify the --bitcoin-branch option (in the scenario from above it would be --bitcoin-branch=bitcoin/master).

Mechanics

The transformations are carried out in a safe way, i.e. certain replacements must not happen (so there is a blacklist to prevent that), as for example the mac build downloads dependencies from bitcoincore.org (the blacklist item would be exactly that bitcoincore.org, i.e. the script does not replace some occurrences if they occur in a certain context).

Also some replacements only happen if they are not preceded or followed by a certain regular expression (contrived example: to replace unt safely but not grunt).

What it does not do

It does not apply certain patches which alter the behavior of the coin. All you get from applying this script is a generic altcoin which works exactly like bitcoin but is named unit-e. It helps, but it does not do everything (and it is not intended to).

Requirements

Clonemachine requires Python 3.6 or later.

Setup

In order to run clonemachine and its tests you need to install its dependencies. You can do so by running pip3 install -r requirements.txt in the root dir of the repository.

Tests

Clonemachine comes with a couple of unit, integration, and regression tests. They can be run through make. See the Makefile for some more details.

All but the unit tests work on checkouts of unit-e and bitcoin in a so it might take a little bit to set up the initial clones. Once they are there, the tests reuse the existing checkouts. Use make clean to delete them and get a clean slate again. The temporary data is stored in a directory tmp in the functional-tests directory.

There is a regression test which compares the changes clonemachine creates with a known good reference. This reference is stored as a diff file in functional--tests/test_data. To create or update the reference data there is the script create_reference_data.py.

If the regression fails, it writes a file diff.diff in the tmp directory. There you can see what changes are different from what is expected. It's a diff of diffs so brace yourself with some abstraction when reading it ;-).

Changes of how substitutions are done

If substitutions are changed in clonemachine so that it substitutes differently than at previous runs, there will be merge conflicts, if the code in the unit-e code base is not adapted accordingly. Clonemachine can be used for that as well. See the --substitute-unit-e-naming option for an example how to do it and test_unit_e_substitutions.py for how to test it.

When changing the rules of how clonemachine does substitutions you can use the following scheme to adapt the unit-e codebase and clonemachine in sync so that they yield the same results:

• Implement a --substitute-unit-e-* option to do the substitutions in the unit-e code base. Use the existing ones as an example.
• Check that you get the desired substitutions by comparing the diff on unit-e
• Adapt the test in test_unit_e_substitutions.py to take the last diff as a base and compare with a newly created one after applying clonemachine.py --substitute-unit-e-*.
• Create a new reference diff by running ./create_reference_data.py in the functional-tests directory.
• Implement the corresponding changes in clonemachine in fork.py.
• Run pytest test_unit_e_substitutions.py to check that the changes have the same result. If they don't you can find the diff in functional-tests/tmp/diff.diff. Iterate until the diff is empty and the test passes.
• Submit pull request for unit-e after applying clonemachine.py --substitute-unit-e-* and for clonemachine commit the changes there.

Contributing

See CONTRIBUTING.md for more information on how to contribute to unit-e-clonemachine.

The Unit-e team is committed to fostering a welcoming and harassment-free environment. All participants are expected to adhere to our code of conduct.

License

unit-e-clonemachine is released under the terms of the MIT license. See COPYING for more information or see https://opensource.org/licenses/MIT.