Use git push instead of git cl

The is easier as git-cl requires installing depot_tools, but there is
one downside. The first time `git push origin HEAD:refs/for/master` is
executed an error may occur:

  $ git push origin HEAD:refs/for/master
  Enumerating objects: 5, done.
  Counting objects: 100% (5/5), done.
  Delta compression using up to 12 threads
  Compressing objects: 100% (3/3), done.
  Writing objects: 100% (3/3), 1.02 KiB | 1.02 MiB/s, done.
  Total 3 (delta 2), reused 0 (delta 0)
  remote: Resolving deltas: 100% (2/2)
  remote: Processing changes: refs: 1, done
  remote: ERROR: commit ed2e8db: missing Change-Id in message footer
  remote:
  remote: Hint: to automatically insert a Change-Id, install the hook:
  remote: f=`git rev-parse --git-dir`/hooks/commit-msg ; mkdir -p $(dirname $f) ; curl -Lo $f https://gerrit-review.googlesource.com/tools/hooks/commit-msg ; chmod +x $f
  remote: and then amend the commit:
  remote:   git commit --amend --no-edit
  remote: Finally, push your changes again
  remote:
  To https://gn.googlesource.com/gn
   ! [remote rejected]   HEAD -> refs/for/master (commit ed2e8db: missing Change-Id in message footer)
  error: failed to push some refs to 'https://gn.googlesource.com/gn'

The suggested solution will install .git/hooks/commit-msg from
https://gerrit-review.googlesource.com/tools/hooks/commit-msg. I find
seeing an error disconcerting but the provided instructions are adequate.

It is possible to install hooks automatically for example:
https://github.com/rycus86/githooks, but I suspect Google already
has a solution.

Change-Id: I15ae79a73e3aab6268a76629111d77a1781c6459
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/6562
Reviewed-by: Brett Wilson <brettw@chromium.org>
Commit-Queue: Brett Wilson <brettw@chromium.org>
2 files changed
tree: 48bbcdb542e6dc8240f5c815d82272a0d88b03ea
  1. build/
  2. docs/
  3. examples/
  4. infra/
  5. misc/
  6. src/
  7. .clang-format
  8. .editorconfig
  9. .gitignore
  10. .style.yapf
  11. AUTHORS
  12. LICENSE
  13. OWNERS
  14. README.md
README.md

GN

GN is a meta-build system that generates build files for Ninja.

Related resources:

Getting a binary

You can download the latest version of GN binary for Linux, macOS and Windows.

Alternatively, you can build GN from source:

git clone https://gn.googlesource.com/gn
cd gn
python build/gen.py
ninja -C out
# To run tests:
out/gn_unittests

On Windows, it is expected that cl.exe, link.exe, and lib.exe can be found in PATH, so you'll want to run from a Visual Studio command prompt, or similar.

On Linux and Mac, the default compiler is clang++, a recent version is expected to be found in PATH. This can be overridden by setting CC, CXX, and AR.

Examples

There is a simple example in examples/simple_build directory that is a good place to get started with the minimal configuration.

To build and run the simple example with the default gcc compiler:

cd examples/simple_build
../../out/gn gen -C out
ninja -C out
./out/hello

For a maximal configuration see the Chromium setup:

and the Fuchsia setup:

Reporting bugs

If you find a bug, you can see if it is known or report it in the bug database.

Sending patches

GN uses Gerrit for code review. The short version of how to patch is:

Register at https://gn-review.googlesource.com.

... edit code ...
ninja -C out && out/gn_unittests

Then, to upload a change for review:

git commit
git push origin HEAD:refs/for/master

When revising a change, use:

git commit --amend
git push origin HEAD:refs/for/master

which will add the new changes to the existing code review, rather than creating a new one.

We ask that all contributors sign Google's Contributor License Agreement (either individual or corporate as appropriate, select ‘any other Google project’).

Community

You may ask questions and follow along with GN‘s development on Chromium’s gn-dev@ Google Group.