blob: 1e0e3bddc7aacb6ae87520d920b2b4d788d2131b [file] [log] [blame]
# This file is used by the GN meta build system to find the root of the source
# tree and to set startup options. For documentation on the values set in this
# file, run "gn help dotfile" at the command line.
# The location of the build configuration file.
buildconfig = "//build/config/"
# The secondary source root is a parallel directory tree where
# GN build files are placed when they can not be placed directly
# in the source tree, e.g. for third party source trees.
secondary_source = "//build/secondary/"
# These are the targets to check headers for by default. The files in targets
# matching these patterns (see "gn help label_pattern" for format) will have
# their includes checked for proper dependencies when you run either
# "gn check" or "gn gen --check".
check_targets = [
#"//apps/*", # Medium-hard.
#"//chrome/*", # Epic number of errors.
#"//extensions/*", # Lots of errors.
#"//media/*", # Lots of errors.
#"//pdf/*", # Medium-hard.
#"//ppapi/*", # Lots of errors.
#"//remoting/*", # Medium-hard.
#"//sandbox/*", # Medium-hard.
#"//third_party/*", # May not ever want this.
#"//ui/*", # Work left on Chromeos w/ use_ozone. Some parts of UI that work:
# These are the list of GN files that run exec_script. This whitelist exists
# to force additional review for new uses of exec_script, which is strongly
# discouraged.
# Most of these entries are for gypi_to_gn calls. We should not be adding new
# calls to this script in the build (see //build/ for detailed
# advice). The only time you should be editing this list for gypi_to_gn
# purposes is when moving an existing call to a different place.
# You should almost never need to add new exec_script calls. exec_script is
# slow, especially on Windows, and can cause confusing effects. Although
# individually each call isn't slow or necessarily very confusing, at the scale
# of our repo things get out of hand quickly. By strongly pushing back on all
# additions, we keep the build fast and clean. If you think you need to add a
# new call, please consider:
# - Do not use a script to check for the existance of a file or directory to
# enable a different mode. Instead, use GN build args to enable or disable
# functionality and set options. An example is checking for a file in the
# src-internal repo to see if the corresponding src-internal feature should
# be enabled. There are several things that can go wrong with this:
# - It's mysterious what causes some things to happen. Although in many cases
# such behavior can be conveniently automatic, GN optimizes for explicit
# and obvious behavior so people can more easily diagnose problems.
# - The user can't enable a mode for one build and not another. With GN build
# args, the user can choose the exact configuration of multiple builds
# using one checkout. But implicitly basing flags on the state of the
# checkout, this functionality is broken.
# - It's easy to get stale files. If for example the user edits the gclient
# to stop checking out src-internal (or any other optional thing), it's
# easy to end up with stale files still mysteriously triggering build
# conditions that are no longer appropriate (yes, this happens in real
# life).
# - Do not use a script to iterate files in a directory (glob):
# - This has the same "stale file" problem as the above discussion. Various
# operations can leave untracked files in the source tree which can cause
# surprising effects.
# - It becomes impossible to use "git grep" to find where a certain file is
# referenced. This operation is very common and people really do get
# confused when things aren't listed.
# - It's easy to screw up. One common case is a build-time script that packs
# up a directory. The author notices that the script isn't re-run when the
# directory is updated, so adds a glob so all the files are listed as
# inputs. This seems to work great... until a file is deleted. When a
# file is deleted, all the inputs the glob lists will still be up to date
# and no command-lines will have been changed. The action will not be
# re-run and the build will be broken. It is possible to get this correct
# using glob, and it's possible to mess it up without glob, but globs make
# this situation much easier to create. if the build always lists the
# files and passes them to a script, it will always be correct.
exec_script_whitelist = [
# TODO(dgn): Layer violation but breaks the build otherwise, see