[gentoo-portage-dev] [PATCH] GitSync: support sync-depth (bug 552814)

[Zac Medico]

Support sync-depth for shallow sync, using git reset --merge just
like in the earlier implementation that was reverted in commit
ab840ac982d3c8b676b89f6bedd14e85dd06870f. Also, use git gc --auto
in order to trigger periodic housekeeping and hopefully avoid
errors from automatic git gc calls as reported in bug 599008.

The default sync-depth is unlimited, which means that default
behavior remains unchanged (unlike the previous implementation that
was reverted).

Bug: https://bugs.gentoo.org/552814
Bug: https://bugs.gentoo.org/599008
---
 man/portage.5                       |  3 ++-
 pym/portage/repository/config.py    |  4 ----
 pym/portage/sync/modules/git/git.py | 26 +++++++++++++++++++++++++-
 3 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/man/portage.5 b/man/portage.5
index acc80791be..a57531d444 100644
--- a/man/portage.5
+++ b/man/portage.5
@@ -985,7 +985,8 @@ overlay filesystems.
 Specifies CVS repository.
 .TP
 .B sync\-depth
-This is a deprecated alias for the \fBclone\-depth\fR option.
+Specifies sync depth to use for DVCS repositories. If set to 0, the
+depth is unlimited. Defaults to 0.
 .TP
 .B sync\-git\-clone\-env
 Set environment variables for git when cloning repository (git clone).
diff --git a/pym/portage/repository/config.py b/pym/portage/repository/config.py
index ad7ae9d180..bf2b6dd03c 100644
--- a/pym/portage/repository/config.py
+++ b/pym/portage/repository/config.py
@@ -179,10 +179,6 @@ class RepoConfig(object):
 		self.clone_depth = repo_opts.get('clone-depth')
 		self.sync_depth = repo_opts.get('sync-depth')
 
-		if self.sync_depth is not None:
-			warnings.warn(_("repos.conf: sync-depth is deprecated,"
-				" use clone-depth instead"))
-
 		self.sync_hooks_only_on_change = repo_opts.get(
 			'sync-hooks-only-on-change', 'false').lower() == 'true'
 
diff --git a/pym/portage/sync/modules/git/git.py b/pym/portage/sync/modules/git/git.py
index 68f8bd1fb9..f99867a34e 100644
--- a/pym/portage/sync/modules/git/git.py
+++ b/pym/portage/sync/modules/git/git.py
@@ -137,6 +137,24 @@ class GitSync(NewBase):
 			writemsg_level(msg + "\n", level=logging.ERROR, noiselevel=-1)
 			return (e.returncode, False)
 
+		shallow = self.repo.sync_depth is not None and self.repo.sync_depth != 0
+		if shallow:
+			git_cmd_opts += " --depth %d" % self.repo.sync_depth
+
+			# For shallow fetch, unreachable objects must be pruned
+			# manually, since otherwise automatic git gc calls will
+			# eventually warn about them (see bug 599008).
+			gc_cmd = ['git', 'gc', '--auto']
+			if quiet:
+				gc_cmd.append('--quiet')
+			exitcode = subprocess.call(gc_cmd,
+				cwd=portage._unicode_encode(self.repo.location))
+			if exitcode != os.EX_OK:
+				msg = "!!! git gc error in %s" % self.repo.location
+				self.logger(self.xterm_titles, msg)
+				writemsg_level(msg + "\n", level=logging.ERROR, noiselevel=-1)
+				return (exitcode, False)
+
 		git_cmd = "%s fetch %s%s" % (self.bin_command,
 			remote_branch.partition('/')[0], git_cmd_opts)
 
@@ -159,7 +177,13 @@ class GitSync(NewBase):
 		if not self.verify_head(revision='refs/remotes/%s' % remote_branch):
 			return (1, False)
 
-		merge_cmd = [self.bin_command, 'merge', 'refs/remotes/%s' % remote_branch]
+		if shallow:
+			# Since the default merge strategy typically fails when
+			# the depth is not unlimited, `git reset --merge`.
+			merge_cmd = [self.bin_command, 'reset', '--merge']
+		else:
+			merge_cmd = [self.bin_command, 'merge']
+		merge_cmd.append('refs/remotes/%s' % remote_branch)
 		if quiet:
 			merge_cmd.append('--quiet')
 		exitcode = subprocess.call(merge_cmd,
-- 
2.13.6