In order to have git run in a fully controlled environment without any
misconfiguration, it may be desirable for users or scripts to override
global- and system-level configuration files. We already have a way of
doing this, which is to unset both HOME and XDG_CONFIG_HOME environment
variables and to set `GIT_CONFIG_NOGLOBAL=true`. This is quite kludgy,
and unsetting the first two variables likely has an impact on other
executables spawned by such a script.
The obvious way to fix this would be to introduce `GIT_CONFIG_NOGLOBAL`
as an equivalent to `GIT_CONFIG_NOSYSTEM`. But in the past, it has
turned out that this design is inflexible: we cannot test system-level
parsing of the git configuration in our test harness because there is no
way to change its location, so all tests run with `GIT_CONFIG_NOSYSTEM`
set.
Instead of doing the same mistake with `GIT_CONFIG_NOGLOBAL`, introduce
two new variables `GIT_CONFIG_GLOBAL` and `GIT_CONFIG_SYSTEM`:
- If unset, git continues to use the usual locations.
- If set to a specific path, we skip reading the normal
configuration files and instead take the path. By setting the path
to `/dev/null`, no configuration will be loaded for the respective
level.
This implements the usecase where we want to execute code in a sanitized
environment without any potential misconfigurations via `/dev/null`, but
is more flexible and allows for more usecases than simply adding
`GIT_CONFIG_NOGLOBAL`.
Signed-off-by: Patrick Steinhardt <ps@xxxxxx>
---
Documentation/git-config.txt | 5 +++
Documentation/git.txt | 10 +++++
config.c | 17 +++++--
t/t1300-config.sh | 86 ++++++++++++++++++++++++++++++++++++
4 files changed, 115 insertions(+), 3 deletions(-)
diff --git a/Documentation/git-config.txt b/Documentation/git-config.txt
index 4b4cc5c5e8..5cddadafd2 100644
--- a/Documentation/git-config.txt
+++ b/Documentation/git-config.txt
@@ -340,6 +340,11 @@ GIT_CONFIG::
Using the "--global" option forces this to ~/.gitconfig. Using the
"--system" option forces this to $(prefix)/etc/gitconfig.
+GIT_CONFIG_GLOBAL::
+GIT_CONFIG_SYSTEM::
+ Take the configuration from the given files instead from global or
+ system-level configuration. See linkgit:git[1] for details.
+
GIT_CONFIG_NOSYSTEM::
Whether to skip reading settings from the system-wide
$(prefix)/etc/gitconfig file. See linkgit:git[1] for details.
diff --git a/Documentation/git.txt b/Documentation/git.txt
index 3a9c44987f..380422a6a9 100644
--- a/Documentation/git.txt
+++ b/Documentation/git.txt
@@ -670,6 +670,16 @@ for further details.
If this environment variable is set to `0`, git will not prompt
on the terminal (e.g., when asking for HTTP authentication).
+`GIT_CONFIG_GLOBAL`::
+`GIT_CONFIG_SYSTEM`::
+ Take the configuration from the given files instead from global or
+ system-level configuration files. If `GIT_CONFIG_SYSTEM` is set, the
+ system config file defined at build time (usually `/etc/gitconfig`)
+ will not be read. Likewise, if `GIT_CONFIG_GLOBAL` is set, neither
+ `$HOME/.gitconfig` nor `$XDG_CONFIG_HOME/git/config` will be read. Can
+ be set to `/dev/null` to skip reading configuration files of the
+ respective level.
+
`GIT_CONFIG_NOSYSTEM`::
Whether to skip reading settings from the system-wide
`$(prefix)/etc/gitconfig` file. This environment variable can
diff --git a/config.c b/config.c
index 161dfaa707..f9c400ad30 100644
--- a/config.c
+++ b/config.c
@@ -1832,13 +1832,24 @@ static int git_config_from_blob_ref(config_fn_t fn,
char *git_system_config(void)
{
+ char *system_config = xstrdup_or_null(getenv("GIT_CONFIG_SYSTEM"));
+ if (system_config)
+ return system_config;
return system_path(ETC_GITCONFIG);
}
-void git_global_config(char **user_config, char **xdg_config)
+void git_global_config(char **user_out, char **xdg_out)
{
- *user_config = expand_user_path("~/.gitconfig", 0);
- *xdg_config = xdg_config_home("config");
+ char *user_config = xstrdup_or_null(getenv("GIT_CONFIG_GLOBAL"));
+ char *xdg_config = NULL;
+
+ if (!user_config) {
+ user_config = expand_user_path("~/.gitconfig", 0);
+ xdg_config = xdg_config_home("config");
+ }
+
+ *user_out = user_config;
+ *xdg_out = xdg_config;
}
/*
diff --git a/t/t1300-config.sh b/t/t1300-config.sh
index e0dd5d65ce..0f92dfe6fb 100755
--- a/t/t1300-config.sh
+++ b/t/t1300-config.sh
@@ -2059,6 +2059,92 @@ test_expect_success '--show-scope with --show-origin' '
test_cmp expect output
'
+test_expect_success 'override global and system config' '
+ test_when_finished rm -f "$HOME"/.config/git &&
+
+ cat >"$HOME"/.gitconfig <<-EOF &&
+ [home]
+ config = true
+ EOF
+ mkdir -p "$HOME"/.config/git &&
+ cat >"$HOME"/.config/git/config <<-EOF &&
+ [xdg]
+ config = true
+ EOF
+ cat >.git/config <<-EOF &&
+ [local]
+ config = true
+ EOF
+ cat >custom-global-config <<-EOF &&
+ [global]
+ config = true
+ EOF
+ cat >custom-system-config <<-EOF &&
+ [system]
+ config = true
+ EOF
+
+ cat >expect <<-EOF &&
+ global xdg.config=true
+ global home.config=true
+ local local.config=true
+ EOF
+ git config --show-scope --list >output &&
+ test_cmp expect output &&
+
+ sane_unset GIT_CONFIG_NOSYSTEM &&
+
+ cat >expect <<-EOF &&
+ system system.config=true
+ global global.config=true
+ local local.config=true
+ EOF
+ GIT_CONFIG_SYSTEM=custom-system-config GIT_CONFIG_GLOBAL=custom-global-config \
+ git config --show-scope --list >output &&
+ test_cmp expect output &&
+
+ cat >expect <<-EOF &&
+ local local.config=true
+ EOF
+ GIT_CONFIG_SYSTEM=/dev/null GIT_CONFIG_GLOBAL=/dev/null git config --show-scope --list >output &&
+ test_cmp expect output
+'
+
+test_expect_success 'override global and system config with missing file' '
+ test_must_fail env GIT_CONFIG_GLOBAL=does-not-exist GIT_CONFIG_SYSTEM=/dev/null git config --global --list &&
+ test_must_fail env GIT_CONFIG_GLOBAL=/dev/null GIT_CONFIG_SYSTEM=does-not-exist git config --system --list &&
+ GIT_CONFIG_GLOBAL=does-not-exist GIT_CONFIG_SYSTEM=does-not-exist git version
+'
+
+test_expect_success 'system override has no effect with GIT_CONFIG_NOSYSTEM' '
+ # `git config --system` has different semantics compared to other
+ # commands as it ignores GIT_CONFIG_NOSYSTEM. We thus test whether the
+ # variable has an effect via a different proxy.
+ cat >alias-config <<-EOF &&
+ [alias]
+ hello-world = !echo "hello world"
+ EOF
+ test_must_fail env GIT_CONFIG_NOSYSTEM=true GIT_CONFIG_SYSTEM=alias-config \
+ git hello-world &&
+ GIT_CONFIG_NOSYSTEM=false GIT_CONFIG_SYSTEM=alias-config \
+ git hello-world >actual &&
+ echo "hello world" >expect &&
+ test_cmp expect actual
+'
+
+test_expect_success 'write to overridden global and system config' '
+ cat >expect <<EOF &&
+[config]
+ key = value
+EOF
+
+ GIT_CONFIG_GLOBAL=write-to-global git config --global config.key value &&
+ test_cmp expect write-to-global &&
+
+ GIT_CONFIG_SYSTEM=write-to-system git config --system config.key value &&
+ test_cmp expect write-to-system
+'
+
for opt in --local --worktree
do
test_expect_success "$opt requires a repo" '
--
2.31.1
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