Reduce memory usage by deleting potentially big objects when they're no longer needed

codearchiver/modules/git.py

@@ -188,8 +188,11 @@ class Git(codearchiver.core.Module):
 				_logger.info(f'Bundling into {bundle}')
 				cmd = ['git', 'bundle', 'create', '--progress', f'../{bundle}', '--stdin', '--reflog', '--all']
 				objectsToExclude = baseOids & commitsAndTags
+				del commitsAndTags
 				input = ''.join(f'^{o}\n' for o in objectsToExclude).encode('ascii')
+				del objectsToExclude
 				status, _, stderr = codearchiver.subprocess.run_with_log(cmd, cwd = directory, input = input, check = False)
+				del input
 				if status == 128 and (stderr == 'fatal: Refusing to create empty bundle.\n' or stderr.endswith('\nfatal: Refusing to create empty bundle.\n')):
 					# Manually write an empty bundle instead
 					# Cf. Documentation/technical/bundle-format.txt and Documentation/technical/pack-format.txt in git's repository for details on the formats
@@ -246,6 +249,7 @@ class Git(codearchiver.core.Module):
 				with open('tmp.idx', 'rb') as fp:
 					_, index, _ = codearchiver.subprocess.run_with_log(['git', 'show-index'], input = fp)
 				indexObjectIds = {oid for offset, oid, _ in map(lambda l: l.rstrip('\n').split(' ', 2), index.splitlines()) if int(offset) < bundlePackSize}
+				del index
 				try:
 					indexObjects = {oid: objects[oid] for oid in indexObjectIds}
 				except KeyError as e:
@@ -258,6 +262,7 @@ class Git(codearchiver.core.Module):
 				_, commitsWithSubmodules, _ = codearchiver.subprocess.run_with_log(['git', 'log', '--format=format:%H', '--diff-filter=d', '--all', '--', '.gitmodules'], cwd = directory)
 				if commitsWithSubmodules:
 					_logger.warning('Submodules found but extraction not supported')
+				del commitsWithSubmodules
 
 				# Ensure that all commits and tags included in the temporary metadata made it into the pack, else data may be lost!
 				indexCommitsAndTags = {oid for oid, otype in indexObjects.items() if otype in ('commit', 'tag')}
@@ -268,6 +273,7 @@ class Git(codearchiver.core.Module):
 						# Already added to metadata earlier
 						continue
 					metadata.append('Object', f'{oid} {otype}')
+				del indexObjects, indexCommitsAndTags
 
 				# Bundling completed without issues; wait for depended-on bundles, add them to the metadata, then replace own temporary metadata
 				if self._storage: