Spectre tips for beginners

This repo holds tips and notes for how to do useful things when getting up to speed with spectre.

Tips for writing new spectre code

Things to do before making a pull request to merge into sxs-collaboration/spectre

• Format your code with git-clang-format-5.0
• Make sure your code compiles by running make -j2 in your build directory (in docker, typically /work/spectre-build-clang). Replace 2 with the number of processors if you're on a machine with more than 2 cores, like a high-end Mac/PC or a cluster. If the process hangs, you might have run out of memory; in that case, try using fewer cores. Fix any compiler errors and warnings you get.
• Also in your build directory, make sure all tests pass with ctest -j2 where 2 is the number of processors.
• For each *.cpp file you created or modified, in your build directory, run make clang-tidy FILE=/path/to/file.cpp. Clang-tidy is a "linter", a tool that helps to find and fix common programming mistakes that the compiler won't catch with a compiler error.
• Make a second build directory, e.g. /work/iwyu-spectre-build-clang and cd into it. Configure as usual, but add the option -DUSE_PCH=OFF to cmake. Then, in the second build directory, for each *.cpp file, run make iwyu FILE=/path/to/*.cpp. This will check that your #include lines. If you get errors from this, check with an experienced spectre developer, as these error messgaes sometimes are wrong.
• In your normal build directory, run make doc. Copy thre docs/html directory outside of docker (if you are using docker), and then open docs/html/index.html in your browser. Make sure documentation you made looks right

How to format your code

For each file you have changed (git status before commit, or look in github after commit), do this, replacing /path/to/file with the path to the file you want to format:

git-clang-format-5.0 -f /path/to/file

This will automagically format only the lines you changed to google style. If you want to reformat an entire file (useful if you made a brand new file), just do

clang-format -i /path/to/file

Git related code snippets etc.

How to update your fork when the code you forked from changes

Here is how you update the develop branch of your fork to get the latest changes from the main spectre repo (called the "upstream repo."

# Set up upstream (first time only)
git remote add upstream ORIGINAL-REPO-LOCATOR
# Update a fork
git fetch upstream
git checkout develop
git merge upstream/develop
git push