don't touch the global ~/.gitconfig

This practice was sus from the very beginning.

3 files changed, 34 insertions, 55 deletions

diff --git a/cgitize/cgit.py b/cgitize/cgit.py
index 547235c..d4a8ae2 100644
--- a/cgitize/cgit.py
+++ b/cgitize/cgit.py
@@ -70,7 +70,7 @@ class AgeFile:
         # Except I think that the committer date, not author date  better
         # represents activity.
         with chdir(repo_dir):
-            success, output = Git.capture(
+            success, output = Git().capture(
                 "for-each-ref",
                 "--sort=-committerdate",
                 "--count=1",
@@ -123,7 +123,7 @@ class CGitRepositories:
             return self._mirror(repo)
 
         with chdir(repo_dir):
-            success, output = Git.capture("rev-parse", "--is-inside-work-tree")
+            success, output = Git().capture("rev-parse", "--is-inside-work-tree")
             if not success:
                 # Overwrite the existing directory if it's not a Git repository.
                 logging.warning(
@@ -132,7 +132,7 @@ class CGitRepositories:
                 )
                 return self._mirror(repo)
 
-            success, output = Git.capture("config", "--get", "remote.origin.url")
+            success, output = Git().capture("config", "--get", "remote.origin.url")
             if not success:
                 # Every repository managed by this script should have the
                 # 'origin' remote. If it doesn't, it's trash. Overwrite the
@@ -171,17 +171,16 @@ class CGitRepositories:
             except Exception as e:
                 logging.exception(e)
                 return False
-        with Git.setup_auth(repo):
-            return Git.check("clone", "--mirror", "--quiet", repo.clone_url, repo_dir)
+        with Git.setup_auth(repo) as git:
+            return git.check("clone", "--mirror", "--quiet", repo.clone_url, repo_dir)
 
     def _fix_upstream_url(self, repo):
         repo_dir = self.get_repo_dir(repo)
         with chdir(repo_dir):
-            return Git.check("remote", "set-url", "origin", repo.clone_url)
+            return Git().check("remote", "set-url", "origin", repo.clone_url)
 
     def _update_existing(self, repo):
         logging.info("Updating repository '%s'", repo.name)
         repo_dir = self.get_repo_dir(repo)
-        with chdir(repo_dir):
-            with Git.setup_auth(repo):
-                return Git.check("remote", "update", "--prune")
+        with chdir(repo_dir), Git.setup_auth(repo) as git:
+            return git.check("remote", "update", "--prune")
diff --git a/cgitize/git.py b/cgitize/git.py
index 4f5eb19..fdb2fef 100644
--- a/cgitize/git.py
+++ b/cgitize/git.py
@@ -5,6 +5,7 @@
 
 from contextlib import contextmanager
 import os
+import tempfile
 
 from cgitize import utils
 
@@ -12,37 +13,21 @@ GIT_ENV = os.environ.copy()
 GIT_ENV["GIT_SSH_COMMAND"] = (
     "ssh -oBatchMode=yes -oLogLevel=QUIET -oStrictHostKeyChecking=no -oUserKnownHostsFile=/dev/null"
 )
+GIT_ENV["GIT_CONFIG_NOSYSTEM"] = "true"
+GIT_ENV["GIT_CONFIG_GLOBAL"] = "/dev/null"
 
 
 class Config:
-    def __init__(self, path):
-        self.path = path
-
-    def exists(self):
-        return os.path.exists(self.path)
-
-    def open(self, mode="r"):
-        return open(self.path, mode=mode, encoding="utf-8")
-
-    def read(self):
-        with self.open(mode="r") as fd:
-            return fd.read()
-
-    def write(self, contents):
-        with self.open(mode="w") as fd:
-            fd.write(contents)
-
-    @contextmanager
-    def backup(self):
-        old_contents = self.read()
-        try:
-            yield old_contents
-        finally:
-            self.write(old_contents)
-
     # What follows is an exteremely loose interpretation of what the .gitconfig
     # syntax is. The source was git-config(1).
 
+    @staticmethod
+    @contextmanager
+    def make_tmp():
+        tmp = tempfile.NamedTemporaryFile(mode="w", encoding="utf-8")
+        with tmp as result, utils.protected_file(result.name):
+            yield result
+
     class Section:
         def __init__(self, name, variables):
             Config.Section.validate_name(name)
@@ -148,31 +133,26 @@ class Config:
 class Git:
     EXE = "git"
 
-    @staticmethod
-    def check(*args, **kwargs):
-        return utils.try_run(Git.EXE, *args, env=GIT_ENV, **kwargs)
+    def __init__(self, config=None):
+        self._env = GIT_ENV.copy()
+        if config is not None:
+            self._env["GIT_CONFIG_GLOBAL"] = config
 
-    @staticmethod
-    def capture(*args, **kwargs):
-        return utils.try_capture(Git.EXE, *args, env=GIT_ENV, **kwargs)
+    def check(self, *args, **kwargs):
+        return utils.try_run(Git.EXE, *args, env=self._env, **kwargs)
 
-    @staticmethod
-    def get_global_config():
-        return Config(os.path.expanduser("~/.gitconfig"))
+    def capture(self, *args, **kwargs):
+        return utils.try_capture(Git.EXE, *args, env=self._env, **kwargs)
 
     @staticmethod
     @contextmanager
     def setup_auth(repo):
         if not repo.url_auth:
-            yield
+            yield Git()
             return
-        config = Git.get_global_config()
-        with utils.protected_file(config.path):
-            with config.backup() as old_contents:
-                variables = [Config.Variable("insteadOf", repo.clone_url)]
-                subsection = Config.Subsection(
-                    "url", repo.clone_url_with_auth, variables
-                )
-                new_contents = f"{old_contents}\n{subsection.format()}"
-                config.write(new_contents)
-                yield
+        with Config.make_tmp() as config:
+            variables = [Config.Variable("insteadOf", repo.clone_url)]
+            subsection = Config.Subsection("url", repo.clone_url_with_auth, variables)
+            config.write(subsection.format())
+            config.flush()
+            yield Git(config.name)
diff --git a/test/integration/lib/common.sh b/test/integration/lib/common.sh
index 10774a7..45dad8c 100644
--- a/test/integration/lib/common.sh
+++ b/test/integration/lib/common.sh
@@ -4,7 +4,7 @@
 # Distributed under the MIT License.
 
 export GIT_CONFIG_NOSYSTEM=true
-#export GIT_CONFIG_GLOBAL=/dev/null
+export GIT_CONFIG_GLOBAL=/dev/null
 
 test_run_cgitize() {
     local cmd=(python3 -m cgitize.main --config "$test_config_path" "$@")