Add envar to replace shallow clones with partial

An investigation go/git-repo-shallow shows a number of problems
when doing a shallow git fetch/clone. This change introduces an
environment variable REPO_ALLOW_SHALLOW. When this environment variable
is set to 1 during a repo init or repo sync all shallow git fetch
commands are replaced with partial fetch commands. Any shallow
repository needing update is unshallowed. This behavior continues until
a subsequent repo sync command is run with REPO_ALLOW_SHALLOW set to 1.

Bug: b/274340522
Change-Id: I1c3188270629359e52449788897d9d4988ebf280
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/374754
Reviewed-by: Josip Sokcevic <sokcevic@google.com>
Tested-by: Jason Chang <jasonnc@google.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/manifest_xml.py b/manifest_xml.py
index 14b03a30..555bf736 100644
--- a/manifest_xml.py
+++ b/manifest_xml.py
@@ -982,6 +982,12 @@ https://gerrit.googlesource.com/git-repo/+/HEAD/docs/manifest-format.md
         return None
 
     @property
+    def CloneFilterForDepth(self):
+        if self.manifestProject.clone_filter_for_depth:
+            return self.manifestProject.clone_filter_for_depth
+        return None
+
+    @property
     def PartialCloneExclude(self):
         exclude = self.manifest.manifestProject.partial_clone_exclude or ""
         return set(x.strip() for x in exclude.split(","))