@matheusbsbs / matheus-bagliano / commits / 4179b4897f

config: allow overriding of global and system configuration

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@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Patrick Steinhardt committed Apr 19, 2021 at 14:31 UTC 4179b4897f2de28858acaebd6382c06c91532e98

4 files changed +115 -3

Documentation/git-config.txt

@@ -340,6 +340,11 @@ GIT_CONFIG::

340 Using the "--global" option forces this to ~/.gitconfig. Using the

341 "--system" option forces this to $(prefix)/etc/gitconfig.

342

343 +GIT_CONFIG_GLOBAL::

344 +GIT_CONFIG_SYSTEM::

345 + Take the configuration from the given files instead from global or

346 + system-level configuration. See linkgit:git[1] for details.

347 +

348 GIT_CONFIG_NOSYSTEM::

349 Whether to skip reading settings from the system-wide

350 $(prefix)/etc/gitconfig file. See linkgit:git[1] for details.

Documentation/git.txt

+10

@@ -670,6 +670,16 @@ for further details.

670 If this environment variable is set to `0`, git will not prompt

671 on the terminal (e.g., when asking for HTTP authentication).

672

673 +`GIT_CONFIG_GLOBAL`::

674 +`GIT_CONFIG_SYSTEM`::

675 + Take the configuration from the given files instead from global or

676 + system-level configuration files. If `GIT_CONFIG_SYSTEM` is set, the

677 + system config file defined at build time (usually `/etc/gitconfig`)

678 + will not be read. Likewise, if `GIT_CONFIG_GLOBAL` is set, neither

679 + `$HOME/.gitconfig` nor `$XDG_CONFIG_HOME/git/config` will be read. Can

680 + be set to `/dev/null` to skip reading configuration files of the

681 + respective level.

682 +

683 `GIT_CONFIG_NOSYSTEM`::

684 Whether to skip reading settings from the system-wide

685 `$(prefix)/etc/gitconfig` file. This environment variable can

config.c

+14 -3

@@ -1846,13 +1846,24 @@ static int git_config_from_blob_ref(config_fn_t fn,

1846

1847 char *git_system_config(void)

1848 {

1849 + char *system_config = xstrdup_or_null(getenv("GIT_CONFIG_SYSTEM"));

1850 + if (system_config)

1851 + return system_config;

1852 return system_path(ETC_GITCONFIG);

1853 }

1854

1852 -void git_global_config(char **user_config, char **xdg_config)

1855 +void git_global_config(char **user_out, char **xdg_out)

1856 {

1854 - *user_config = expand_user_path("~/.gitconfig", 0);

1855 - *xdg_config = xdg_config_home("config");

1857 + char *user_config = xstrdup_or_null(getenv("GIT_CONFIG_GLOBAL"));

1858 + char *xdg_config = NULL;

1859 +

1860 + if (!user_config) {

1861 + user_config = expand_user_path("~/.gitconfig", 0);

1862 + xdg_config = xdg_config_home("config");

1863 + }

1864 +

1865 + *user_out = user_config;

1866 + *xdg_out = xdg_config;

1867 }

1868

1869 /*

t/t1300-config.sh

+86

@@ -2059,6 +2059,92 @@ test_expect_success '--show-scope with --show-origin' '

2059 test_cmp expect output

2060 '

2061

2062 +test_expect_success 'override global and system config' '

2063 + test_when_finished rm -f "$HOME"/.config/git &&

2064 +

2065 + cat >"$HOME"/.gitconfig <<-EOF &&

2066 + [home]

2067 + config = true

2068 + EOF

2069 + mkdir -p "$HOME"/.config/git &&

2070 + cat >"$HOME"/.config/git/config <<-EOF &&

2071 + [xdg]

2072 + config = true

2073 + EOF

2074 + cat >.git/config <<-EOF &&

2075 + [local]

2076 + config = true

2077 + EOF

2078 + cat >custom-global-config <<-EOF &&

2079 + [global]

2080 + config = true

2081 + EOF

2082 + cat >custom-system-config <<-EOF &&

2083 + [system]

2084 + config = true

2085 + EOF

2086 +

2087 + cat >expect <<-EOF &&

2088 + global xdg.config=true

2089 + global home.config=true

2090 + local local.config=true

2091 + EOF

2092 + git config --show-scope --list >output &&

2093 + test_cmp expect output &&

2094 +

2095 + sane_unset GIT_CONFIG_NOSYSTEM &&

2096 +

2097 + cat >expect <<-EOF &&

2098 + system system.config=true

2099 + global global.config=true

2100 + local local.config=true

2101 + EOF

2102 + GIT_CONFIG_SYSTEM=custom-system-config GIT_CONFIG_GLOBAL=custom-global-config \

2103 + git config --show-scope --list >output &&

2104 + test_cmp expect output &&

2105 +

2106 + cat >expect <<-EOF &&

2107 + local local.config=true

2108 + EOF

2109 + GIT_CONFIG_SYSTEM=/dev/null GIT_CONFIG_GLOBAL=/dev/null git config --show-scope --list >output &&

2110 + test_cmp expect output

2111 +'

2112 +

2113 +test_expect_success 'override global and system config with missing file' '

2114 + test_must_fail env GIT_CONFIG_GLOBAL=does-not-exist GIT_CONFIG_SYSTEM=/dev/null git config --global --list &&

2115 + test_must_fail env GIT_CONFIG_GLOBAL=/dev/null GIT_CONFIG_SYSTEM=does-not-exist git config --system --list &&

2116 + GIT_CONFIG_GLOBAL=does-not-exist GIT_CONFIG_SYSTEM=does-not-exist git version

2117 +'

2118 +

2119 +test_expect_success 'system override has no effect with GIT_CONFIG_NOSYSTEM' '

2120 + # `git config --system` has different semantics compared to other

2121 + # commands as it ignores GIT_CONFIG_NOSYSTEM. We thus test whether the

2122 + # variable has an effect via a different proxy.

2123 + cat >alias-config <<-EOF &&

2124 + [alias]

2125 + hello-world = !echo "hello world"

2126 + EOF

2127 + test_must_fail env GIT_CONFIG_NOSYSTEM=true GIT_CONFIG_SYSTEM=alias-config \

2128 + git hello-world &&

2129 + GIT_CONFIG_NOSYSTEM=false GIT_CONFIG_SYSTEM=alias-config \

2130 + git hello-world >actual &&

2131 + echo "hello world" >expect &&

2132 + test_cmp expect actual

2133 +'

2134 +

2135 +test_expect_success 'write to overridden global and system config' '

2136 + cat >expect <<EOF &&

2137 +[config]

2138 + key = value

2139 +EOF

2140 +

2141 + GIT_CONFIG_GLOBAL=write-to-global git config --global config.key value &&

2142 + test_cmp expect write-to-global &&

2143 +

2144 + GIT_CONFIG_SYSTEM=write-to-system git config --system config.key value &&

2145 + test_cmp expect write-to-system

2146 +'

2147 +

2148 for opt in --local --worktree

2149 do

2150 test_expect_success "$opt requires a repo" '