Bitcoin Core integration/staging tree
What is Bitcoin?
Bitcoin is an experimental new digital currency that enables instant payments to anyone, anywhere in the world. Bitcoin uses peer-to-peer technology to operate with no central authority: managing transactions and issuing money are carried out collectively by the network. Bitcoin Core is the name of open source software which enables the use of this currency.
For more information, as well as an immediately useable, binary version of the Bitcoin Core software, see https://www.bitcoin.org/en/download.
Developers work in their own trees, then submit pull requests when they think their feature or bug fix is ready.
If it is a simple/trivial/non-controversial change, then one of the Bitcoin development team members simply pulls it.
If it is a more complicated or potentially controversial change, then the patch submitter will be asked to start a discussion (if they haven't already) on the mailing list.
The patch will be accepted if there is broad consensus that it is a good thing. Developers should expect to rework and resubmit patches if the code doesn't match the project's coding conventions (see doc/coding.md) or are controversial.
master branch is regularly built and tested, but is not guaranteed to be
completely stable. Tags are created
regularly to indicate new official, stable release versions of Bitcoin.
Testing and code review is the bottleneck for development; we get more pull requests than we can review and test on short notice. Please be patient and help out by testing other people's pull requests, and remember this is a security-critical project where any mistake might cost people lots of money.
Developers are strongly encouraged to write unit tests for new code, and to
submit new unit tests for old code. Unit tests can be compiled and run (assuming they weren't disabled in configure) with:
Every pull request is built for both Windows and Linux on a dedicated server, and unit and sanity tests are automatically run. The binaries produced may be used for manual QA testing — a link to them will appear in a comment on the pull request posted by BitcoinPullTester. See https://github.com/TheBlueMatt/test-scripts for the build/test scripts.
Manual Quality Assurance (QA) Testing
Large changes should have a test plan, and should be tested by somebody other than the developer who wrote the code. See https://github.com/bitcoin/QA/ for how to create a test plan.
Changes to translations as well as new translations can be submitted to Bitcoin Core's Transifex page.
Translations are periodically pulled from Transifex and merged into the git repository. See the translation process for details on how this works.
Important: We do not accept translation changes as GitHub pull requests because the next pull from Transifex would automatically overwrite them again.
Translators should also subscribe to the mailing list.
Development tips and tricks
compiling for debugging
Run configure with the --enable-debug option, then make. Or run configure with CXXFLAGS="-g -ggdb -O0" or whatever debug flags you need.
If the code is behaving strangely, take a look in the debug.log file in the data directory; error and debugging messages are written there.
The -debug=... command-line option controls debugging; running with just -debug will turn on all categories (and give you a very large debug.log file).
The Qt code routes qDebug() output to debug.log under category "qt": run with -debug=qt to see it.
testnet and regtest modes
Run with the -testnet option to run with "play bitcoins" on the test network, if you are testing multi-machine code that needs to operate across the internet.
If you are testing something that can run on one machine, run with the -regtest option. In regression test mode, blocks can be created on-demand; see qa/rpc-tests/ for tests that run in -regtest mode.
Bitcoin Core is a multithreaded application, and deadlocks or other multithreading bugs can be very difficult to track down. Compiling with -DDEBUG_LOCKORDER (configure CXXFLAGS="-DDEBUG_LOCKORDER -g") inserts run-time checks to keep track of which locks are held, and adds warnings to the debug.log file if inconsistencies are detected.