On Mon, Apr 15, 2019 at 01:39:47PM -0700, Jeff Hostetler via GitGitGadget wrote:
> From: Jeff Hostetler <jeffhost@xxxxxxxxxxxxx>
>
> Teach git to read the system and global config files for
> default Trace2 settings. This allows system-wide Trace2 settings to
> be installed and inherited to make it easier to manage a collection of
> systems.
>
> The original GIT_TR2* environment variables are loaded afterwards and
> can be used to override the system settings.
>
> Only the system and global config files are used. Repo and worktree
> local config files are ignored. Likewise, the "-c" command line
> arguments are also ignored. These limits are for performance reasons.
>
> (1) For users not using Trace2, there should be minimal overhead to
> detect that Trace2 is not enabled. In particular, Trace2 should not
> allocate lots of otherwise unused data strucutres.
>
> (2) For accurate performance measurements, Trace2 should be initialized
> as early in the git process as possible, and before most of the normal
> git process initialization (which involves discovering the .git directory
> and reading a hierarchy of config files).
Reading the configuration that early causes unexpected and undesired
behavior change:
$ sudo chmod a-rwx /usr/local/etc/gitconfig
$ ./BUILDS/v2.21.0/bin/git
usage: git [--version] [--help] [-C <path>] [-c <name>=<value>]
<... snip rest of usage ...>
$ strace ./BUILDS/v2.21.0/bin/git 2>&1 |grep config -c
0
$ ./git
fatal: unable to access '/usr/local/etc/gitconfig': Permission denied
$ ./git --version
fatal: unable to access '/usr/local/etc/gitconfig': Permission denied
I think at least 'git', 'git --help', and 'git --version' should Just
Work, no matter what.
This breaks the 32 bit Linux build job on Travis CI, because:
- In the 32 bit Docker image we change UID from root to regular user
while preserving the environment, including $HOME.
- Since $HOME is the default build prefix, Git will look for the
system-wide configuration under '/root/etc/gitconfig', which fails
as a regular user.
- Our test harness checks early (i.e. earlier than setting
GIT_CONFIG_NOSYSTEM=1) whether Git has been built successfully by
attempting to run '$GIT_BUILD_DIR}/git', which fails because of
the inaccessible system-wide config file, and in turn the harness
assumes that Git hasn't been built and aborts.
https://travis-ci.org/git/git/jobs/524403682#L1258
