Don't calculate diffs ....

Instead of calculating diffs, just apply the revision to the branch
as-is. If things don't match, update them. Done.

Problems happens if there are devel project changes and histories
are no longer linear and the diffs are not calculated properly.
eg. trytond_stock_lot devel branch was imported incorrectly

lib/git_exporter.py

@@ -2,6 +2,8 @@ import logging
 import os
 
 import yaml
+from hashlib import md5
+from pathlib import Path
 
 from lib.binary import is_binary_or_large
 from lib.db import DB
@@ -133,6 +135,12 @@ class GitExporter:
             return True
         return flat.parent1 == branch_state[flat.branch]
 
+    def file_md5(self, file):
+        m = md5()
+        with open(file, 'rb') as f:
+            m.update(f.read())
+        return m.hexdigest()
+
     def commit_flat(self, flat, branch_state):
         parents = []
         self.git.checkout(flat.branch)
@@ -151,11 +159,40 @@ class GitExporter:
         # create file if not existant
         self.git.add_default_lfs_gitattributes(force=False)
 
-        to_download, to_delete = flat.commit.calc_delta(branch_state[flat.branch])
-        for file in to_delete:
-            self.git.remove(file)
-        for file, size, md5 in to_download:
-            self.commit_file(flat, file, size, md5)
+        new_files = flat.commit.files_list()
+        cur_files = os.listdir(self.git.path)
+        for cf in cur_files:
+            if cf[0] == '.':
+                continue
+            found = False
+            for nf in new_files:
+                if nf['name'] == cf:
+                    found = True
+                    break
+
+            if found:
+                # check if file is modified
+                file_path = self.git.path.joinpath(cf)
+                stat = file_path.stat()
+                if stat.st_size != nf['size'] or self.file_md5(file_path) != nf['md5']:
+                    logging.debug(f"updating {file_path.name}")
+                    self.commit_file(flat, Path(cf), nf['size'], nf['md5'])
+                else:
+                    logging.debug(f"leaving  {file_path.name}")
+            else:
+                # file not exist in new commit
+                self.git.remove(Path(cf))
+
+
+        # new files?
+        for file in new_files:
+            found = False
+            for cf in cur_files:
+                if file['name'] == cf:
+                    found = True
+                    break
+            if not found:
+                self.commit_file(flat, Path(file['name']), file['size'], file['md5'])
 
         commit = self.git.commit(
             flat.user.realname,