[format] Convert invalid whitespace to space when loading for format

I've been forced to edit a lot of Go code recently where tabs are much
loved, and my Vim occasionally gets horked and sneaks tabs into my .gn
files.

After that, running `gn format` on the BUILD.gn complains about

    ERROR at //.../BUILD.gn:5:1: Invalid token.
            sources = [
    ^
    You got a tab character in here. Tabs are evil. Convert to spaces.

It just seems petty to make me manually replace them! So only when
parsing for format purposes, silently transform tabs (and since we're
here vertical tabs and form feeds too) to spaces outside of quoted
strings. Maintain the error in normal operation though.

Change-Id: Ia4099be3bbd9621e75479d4bfa734862f6c5bccf
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/6500
Reviewed-by: Brett Wilson <brettw@chromium.org>
Commit-Queue: Brett Wilson <brettw@chromium.org>
7 files changed
tree: 3401170ce7308ec91693c3f247a9101373784e0f
  1. .clang-format
  2. .editorconfig
  3. .gitignore
  4. .style.yapf
  5. AUTHORS
  6. LICENSE
  7. OWNERS
  8. README.md
  9. build/
  10. docs/
  11. examples/
  12. infra/
  13. misc/
  14. src/
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.

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 cl upload --gerrit

When revising a change, use:

git commit --amend
git cl upload --gerrit

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.