The Zcash repository, https://github.com/zcash/zcash, is a fork of Bitcoin Core release 0.11.2 (some upstream PRs merged in). It implements the Zcash protocol and a few other distinct features.
Zcash Github Workflow¶
This document describes the standard workflows and terminology for developers at Zcash. It is intended to provide procedures that will allow users to contribute to the open-source code base. Below are common workflows users will encounter:
Before continuing, please ensure you have an existing Github or Gitlab account. If not, visit Github or Gitlab to create an account.
Fork Zcash Repository and Connect to Upstream¶
First, fork the zcash repository by navigating to the respository and clicking the ‘fork’ icon at the top right corner of the page (standard github forking instructions).
Then, open up a terminal and issue the below commands to connect to upstream:
your_username, with your actual Github username
git clone email@example.com:your_username/zcash.git cd zcash git remote add upstream firstname.lastname@example.org:zcash/zcash.git git remote set-url --push upstream DISABLED git fetch upstream git branch -u upstream/main main
After issuing the above commands, your
.git/config file should look similar to the following:
[core] repositoryformatversion = 0 filemode = true bare = false logallrefupdates = true [remote "origin"] url = email@example.com:your_username/zcash.git fetch = +refs/heads/*:refs/remotes/origin/* [branch "main"] remote = upstream merge = refs/heads/main [remote "upstream"] url = firstname.lastname@example.org:zcash/zcash.git fetch = +refs/heads/*:refs/remotes/upstream/* pushurl = DISABLED
This setup provides a single cloned environment to develop for Zcash starting with a new Github/Gitlab environment. There are alternative methods using multiple clones, but this document does not cover that process.
While working on the Zcash project, you are going to have bugs, features, and ideas to work on. Branching exists to aid these different tasks while you write code. Below are some conventions of branching at Zcash:
mainbranch is ALWAYS deployable.
- Branch names MUST be descriptive (e.g.
To create a new branch (assuming you are in
git checkout -b [new_branch_name]
Even though you have created a new branch, until you
git push this local branch, it will not show up in your Zcash fork on Github (e.g. https://github.com/your_username/zcash)
To checkout an existing branch (assuming you are in
git checkout [existing_branch_name]
If you are fixing a bug or implementing a new feature, you likely will want to create a new branch. If you are reviewing code or working on existing branches, you likely will checkout an existing branch. To view the list of current Zcash Github issues, click here .
Make & Commit Changes¶
If you have created a new branch or checked out an existing one, it is time to make changes to your local source code. Below are some formalities for commits:
- Commit messages MUST be clear.
- Commit messages MUST be descriptive.
- Commit messages MUST be clean (see Squashing Commits for details).
Commit messages should contain enough information in the first line to be able to scan a list of patches and identify which one is being searched for. You MAY use “auto-close” keywords, but it’s not necessary. The auto-close keywords are “close[ds]”, “resolve[ds]”, nd “fix(e[ds])?”
While continuing to do development on a branch, keep in mind that other approved commits
are getting merged into
main. In order to ensure there are minimal to no merge conflicts,
rebase with main.
If you are new to this process, please sanity check your remotes:
git remote -v
origin email@example.com:your_username/zcash.git (fetch) origin firstname.lastname@example.org:your_username/zcash.git (push) upstream email@example.com:zcash/zcash.git (fetch) upstream DISABLED (push)
This output should be consistent with your
[branch "main"] remote = upstream merge = refs/heads/main [remote "origin"] url = firstname.lastname@example.org:your_username/zcash.git fetch = +refs/heads/*:refs/remotes/origin/* [remote "upstream"] url = email@example.com:zcash/zcash.git fetch = +refs/heads/*:refs/remotes/upstream/* pushurl = DISABLED
Once you have confirmed your branch/remote is valid, issue the following commands (assumes you have NO existing uncommitted changes):
git pull --rebase upstream main git push -f
If you have uncommitted changes, use
git stash to preserve them:
git stash git pull --rebase upstream main git push -f git stash pop
git stash allows you to temporarily store your changes while you rebase
main. Without this, you will rebase with main and lose your local changes.
Before committing changes, ensure your commit messages follow these guidelines:
- Separate subject from body with a blank line.
- Limit the subject line to 50 characters.
- Capitalize the subject line.
- Do not end the subject line with a period.
- If changing the
zcash/zipsrepo, start the subject with “ZIP <number>:” or “Protocol spec:”.
- Wrap the body at 72 characters.
- Use the body to explain what and why vs. how.
(The line limits are guidelines, they’re not essential.)
Once synced with
main, let’s commit our changes:
git add [files...] # default is all files, be careful not to add unintended files git commit -m 'Message describing commit' git push origin [branch-name]
Now that all the files changed have been committed, let’s continue to Create Pull Request section.
Create Pull Request¶
On your GitHub page (e.g. https://github.com/your_username/zcash), you will notice a newly created
banner containing your recent commit with a big green
Compare & pull request button. Click on it.
First, write a brief summary comment for your PR – this first comment should be no more than a few lines because it ends up in the merge commit message. This comment should mention the issue number preceded by a hash symbol (e.g. #2984).
Add a second comment if more explanation is needed. It’s important to explain why this pull request should be accepted. State whether the proposed change fixes part of the problem or all of it; if the change is temporary (a workaround) or permanent; if the problem also exists upstream (Bitcoin) and, if so, if and how it was fixed there.
If you click on Commits, you should see the diff of that commit; it’s advisable to verify it’s what you expect. You can also click on the small plus signs that appear when you hover over the lines on either the left or right side and add a comment specific to that part of the code. This is very helpful, as you don’t have to tell the reviewers (in a general comment) that you’re referring to a certain line in a certain file.
Add comments before adding reviewers, otherwise they will get a separate email for each comment you add. Once you’re happy with the documentation you’ve added to your PR, select reviewers along the right side. For a trivial change (like the example here), one reviewer is enough, but generally you should have at least two reviewers, at least one of whom should be experienced. It may be good to add one less experienced engineer as a learning experience for that person.
Discuss / Review PR¶
In order to merge your PR with
main, you will need to convince the reviewers of the intentions of your code.
If your PR introduces code that does not have existing tests to ensure it operates gracefully, you MUST also create these tests to accompany your PR.
Reviewers will investigate your PR and provide feedback. Generally the comments are explicitly requesting code changes or clarifying implementations. Otherwise Reviewers will reply with PR terminology:
- Concept ACK - Agree with the idea and overall direction, but have neither reviewed nor tested the code changes.
- utACK (untested ACK) - Reviewed and agree with the code changes but haven’t actually tested them.
- Tested ACK - Reviewed the code changes and have verified the functionality or bug fix.
- ACK - A loose ACK can be confusing. It’s best to avoid them unless it’s a documentation/comment only change in which case there is nothing to test/verify; therefore the tested/untested distinction is not there.
- NACK - Disagree with the code changes/concept. Should be accompanied by an explanation.
Before your PR is accepted, you might be requested to squash your commits to clean up the logs. This can be done using the following approach:
git checkout branch_name git rebase -i HEAD~4
The integer value after
~ represents the number of commits you would like to interactively rebase.
You can pick a value that makes sense for your situation. A template will pop-up in your terminal
requesting you to specify what commands you would like to do with each prior commit:
Commands: p, pick = use commit r, reword = use commit, but edit the commit message e, edit = use commit, but stop for amending s, squash = use commit, but meld into previous commit f, fixup = like "squash", but discard this commit's log message x, exec = run command (the rest of the line) using shell
Modify each line with the according command, followed by the hash of the commit. You can also reorder commits by reordering lines. For example, if I wanted to squash my last 4 commits into the most recent commit for this PR:
p 1fc6c95 Final commit message s 6b2481b Third commit message s dd1475d Second commit message s c619268 First commit message
git push origin branch-name --force
Deploy / Merge PR¶
We use a homu instance called
zkbot to merge all PRs in
zcash/zcash. (Direct pushing to the
main branch of the repo is not allowed.)
Here’s just a quick overview of how it works.
If you’re on our team, you can do
@zkbot <command> to tell zkbot to do things. Here are a few examples:
r+ [commithash]this will test the merge and then actually commit the merge into the repo if the tests succeed.
trythis will test the merge and nothing else.
rollupthis is like
r+but for insignificant changes. Use this when we want to test a bunch of merges at once to save Buildbot time. (In practice we don’t often use
More instructions are found here: https://ci.z.cash/homu
Once you have addressed the comments in your PR, and it has received two ACKs from reviewers, you can attempt to test merge the PR:
@zkbot commands are entered into Github tickets as comments
This will instruct our Buildbot CI system to test merging your PR with
main and ensure
it passes the full test suite. You may or may not have permissions to run this command, but
zkbot will reply with output indicating if you can or not.
@zkbot try fails, you will need to go back and address the issues accordingly.
Otherwise, you can now attempt to merge into
@zkbot commands are entered into GitHub tickets as comments
There are very few people that have
@zkbot r+ privileges, so you can request one of these
people to merge the PR, or leave it for the release process to pick it up. Finally, when the
PR is merged into
main successfully, your PR will close.
There will be times when your PR is waiting for some portion of the above process. If you
are requested to rebase your PR, in order to gracefully merge into
main, please do the following:
git checkout branch_name git pull --rebase upstream main git push -f
Zcash Developer Workflow¶
The flow below assumes you have already downloaded the parameters using
Below describes a standard workflow for developing code in the zcash repository:
- Clone your zcash fork
- git clone firstname.lastname@example.org:your_username/zcash.git
- Create a branch for local changes
- cd zcash git checkout -b [new_branch_name]
- Build zcash
- /zcutil/build.sh -j$(nproc)
- Create & build changes to code
- Run Zcashd
Logs are always written to
debug.log in the data directory unless the
-nodebuglogfile flag is specified. Use the
-debug=category flag to enable specific debug logging categories. Include the
-printtoconsole flag to stream logs to
This will allow you to create/edit existing Zcash code, and build it locally. If you want to submit a PR for this newly created code, please refer back to Make & Commit Changes section. After completing those steps, please ensure you have also followed Create Pull Request and Deploy / Merge PR sections.
See the Developer notes documentation which details coding style, thread handling and additional tips.
To ensure the existing Zcash code is tested, we use the following tools:
Add unit tests for Zcash under
To list all tests, run
To run a subset of tests, use a regular expression with the flag
To run a subset of BOOST tests:
src/test/test_bitcoin -t TESTGROUP/TESTNAME
To run the main test suite:
To run the RPC tests:
or for a single test implemented in
The main test suite uses two different testing frameworks. Tests using the Boost
framework are under
src/test/; tests using the Google Test/Google Mock framework
src/wallet/gtest/. The latter framework is preferred
for new Zcash unit tests.
RPC tests are implemented in Python under the qa/rpc-tests/ directory.
Starting from Zcash v1.0.0-beta1, Zcash version numbers and release tags take one of the following forms:
Alpha releases used a different convention:
v0.11.2.z<N> (because Zcash was forked from Bitcoin v0.11.2).
For details on zcashd release processes, see: