pmb.helpers.git.clone: use git from host system (!1845)

Do not install git in the native chroot and use it from there. Remove the
chown_to_user argument from pmb.helpers.git.clone(), the resulting dir
is now always owned by the user. While at it, refactor the function and
display the clone URL.

Previously we had cloned aports_upstream (from Alpine) with
chown_to_user=False (legacy) and pmaports with chown_to_user=True.
pmb.helpers.git.rev_parse() would only work after chown_to_user=True.

Check if git is installed in "pmbootstrap init", and remove the same
check from rev_parse(). Add a new work dir version, that checks for git
and changes ownership of already checked out aports_upstream to the
host system's user.

When creating a new work dir, create cache_git instead of cache_http.
cache_http is created on demand already, with proper permissions. But
cache_git must be created, otherwise pmb.helpers.mount.bind will create it
as root.

This is in preparation for the "pmbootstrap pull" feature, as it allows
using the host system's git in all new code paths. We will be able to
handle repositories even if they were cloned outside of the work dir
(which we do in a few CI scripts for example).

Related: #1858

pmb/helpers/git.py

@@ -18,7 +18,6 @@ along with pmbootstrap.  If not, see <http://www.gnu.org/licenses/>.
 """
 import logging
 import os
-import shutil
 
 import pmb.build
 import pmb.chroot.apk
@@ -26,55 +25,37 @@ import pmb.config
 import pmb.helpers.run
 
 
-def clone(args, name_repo, shallow=True, chown_to_user=False):
+def clone(args, name_repo, shallow=True):
+    """ Clone a git repository to $WORK/cache_git/$name_repo.
+
+        :param name_repo: short alias used for the repository name, from
+                          pmb.config.git_repos (e.g. "aports_upstream",
+                          "pmaports")
+        :param shallow: only clone the last revision of the repository, instead
+                        of the entire repository (faster, saves bandwith) """
     # Check for repo name in the config
     if name_repo not in pmb.config.git_repos:
         raise ValueError("No git repository configured for " + name_repo)
 
     # Skip if already checked out
-    if os.path.exists(args.work + "/cache_git/" + name_repo):
+    path = args.work + "/cache_git/" + name_repo
+    if os.path.exists(path):
         return
 
-    # Check out to temp folder
-    name_temp = name_repo + ".temp"
-    if not os.path.exists(args.work + "/cache_git/" + name_temp):
-        # Set up chroot and install git
-        pmb.chroot.apk.install(args, ["git"])
-        logging.info("(native) git clone " + pmb.config.git_repos[name_repo])
+    # Build git command
+    url = pmb.config.git_repos[name_repo]
+    command = ["git", "clone"]
+    if shallow:
+        command += ["--depth=1"]
+    command += [url, path]
 
-        # git options
-        options = []
-        if shallow:
-            options += ["--depth=1"]
-
-        # Run the command
-        pmb.chroot.user(args, ["git", "clone"] + options +
-                              [pmb.config.git_repos[name_repo], name_temp],
-                        working_dir="/home/pmos/git/", check=False,
-                        output="stdout")
-        if not os.path.exists(args.work + "/cache_git/" + name_temp):
-            logging.info("NOTE: cloning from git is known to fail when the"
-                         " host linux kernel is older than 3.17:"
-                         " <https://postmarketos.org/oldkernel>")
-            raise RuntimeError("git clone failed!")
-
-    # Chown to user's UID and GID
-    if chown_to_user:
-        uid_gid = "{}:{}".format(os.getuid(), os.getgid())
-        pmb.helpers.run.root(args, ["chown", "-R", uid_gid, args.work +
-                                    "/cache_git/" + name_temp])
-
-    # Rename the temp folder
-    pmb.helpers.run.root(args, ["mv", name_temp, name_repo],
-                         args.work + "/cache_git")
+    # Create parent dir and clone
+    logging.info("Clone git repository: " + url)
+    os.makedirs(args.work + "/cache_git", exist_ok=True)
+    pmb.helpers.run.user(args, command, output="stdout")
 
 
 def rev_parse(args, revision="HEAD"):
-    if shutil.which("git") is None:
-        logging.warning("WARNING: Cannot determine revision of git " +
-                        "repository at " + args.aports + ". Command 'git' " +
-                        "not found.")
-        return ""
     rev = pmb.helpers.run.user(args, ["git", "rev-parse", revision],
                                args.aports, output_return=True, check=False)
     if rev is None: