Only fetch lfs files for specific git_ref (#5202)

conda_build/source.py

@@ -202,19 +202,19 @@ def unpack(
             shutil.move(os.path.join(tmpdir, f), os.path.join(src_dir, f))
 
 
-def check_git_lfs(git, cwd):
+def check_git_lfs(git, cwd, git_ref):
     try:
-        lfs_list_output = check_output_env([git, "lfs", "ls-files", "--all"], cwd=cwd)
+        lfs_list_output = check_output_env([git, "lfs", "ls-files", git_ref], cwd=cwd)
         return lfs_list_output and lfs_list_output.strip()
     except CalledProcessError:
         return False
 
 
-def git_lfs_fetch(git, cwd, stdout, stderr):
+def git_lfs_fetch(git, cwd, git_ref, stdout, stderr):
     lfs_version = check_output_env([git, "lfs", "version"], cwd=cwd)
     log.info(lfs_version)
     check_call_env(
-        [git, "lfs", "fetch", "origin", "--all"], cwd=cwd, stdout=stdout, stderr=stderr
+        [git, "lfs", "fetch", "origin", git_ref], cwd=cwd, stdout=stdout, stderr=stderr
     )
 
 
@@ -273,8 +273,8 @@ def git_mirror_checkout_recursive(
                 check_call_env(
                     [git, "fetch"], cwd=mirror_dir, stdout=stdout, stderr=stderr
                 )
-                if check_git_lfs(git, mirror_dir):
-                    git_lfs_fetch(git, mirror_dir, stdout, stderr)
+                if check_git_lfs(git, mirror_dir, git_ref):
+                    git_lfs_fetch(git, mirror_dir, git_ref, stdout, stderr)
             else:
                 # Unlike 'git clone', fetch doesn't automatically update the cache's HEAD,
                 # So here we explicitly store the remote HEAD in the cache's local refs/heads,
@@ -318,8 +318,8 @@ def git_mirror_checkout_recursive(
             check_call_env(
                 args + [git_url, git_mirror_dir], stdout=stdout, stderr=stderr
             )
-            if check_git_lfs(git, mirror_dir):
-                git_lfs_fetch(git, mirror_dir, stdout, stderr)
+            if check_git_lfs(git, mirror_dir, git_ref):
+                git_lfs_fetch(git, mirror_dir, git_ref, stdout, stderr)
         except CalledProcessError:
             # on windows, remote URL comes back to us as cygwin or msys format.  Python doesn't
             # know how to normalize it.  Need to convert it to a windows path.