[18.0][IMP] fs_attachment: improve attachment storage handling of files without body (size=0)

[CRogos]

Uploading an 0kb documents runs into this error. This also affects incoming mails with e.g. tracking images (helpdesk/vendorbills).

RPC_ERROR

Odoo Server Error

Occured on c4a8.odoo.com on model account.journal on 2026-04-21 13:36:19 GMT

Traceback (most recent call last):
  File "/home/odoo/src/odoo/odoo/http.py", line 2167, in _transactioning
    return service_model.retrying(func, env=self.env)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/odoo/src/odoo/odoo/service/model.py", line 157, in retrying
    result = func()
             ^^^^^^
  File "/home/odoo/src/odoo/odoo/http.py", line 2134, in _serve_ir_http
    response = self.dispatcher.dispatch(rule.endpoint, args)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/odoo/src/odoo/odoo/http.py", line 2382, in dispatch
    result = self.request.registry['ir.http']._dispatch(endpoint)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/odoo/src/odoo/odoo/addons/base/models/ir_http.py", line 333, in _dispatch
    result = endpoint(**request.params)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/odoo/src/odoo/odoo/http.py", line 754, in route_wrapper
    result = endpoint(self, *args, **params_ok)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/odoo/src/odoo/addons/web/controllers/dataset.py", line 36, in call_kw
    return call_kw(request.env[model], method, args, kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/odoo/src/odoo/odoo/api.py", line 535, in call_kw
    result = getattr(recs, name)(*args, **kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/odoo/src/enterprise/documents_account/models/account_journal.py", line 13, in create_document_from_attachment
    action = super().create_document_from_attachment(attachment_ids)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/odoo/src/enterprise/account_bank_statement_import/models/account_journal.py", line 31, in create_document_from_attachment
    return super().create_document_from_attachment(attachment_ids)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/odoo/src/odoo/addons/account/models/account_journal.py", line 988, in create_document_from_attachment
    invoices = self._create_document_from_attachment(attachment_ids)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/odoo/src/odoo/addons/account/models/account_journal.py", line 970, in _create_document_from_attachment
    invoice.with_context(skip_is_manually_modified=True)._extend_with_attachments(attachment, new=True)
  File "/home/odoo/src/odoo/addons/account/models/account_move.py", line 4344, in _extend_with_attachments
    file_data_list = attachments._unwrap_edi_attachments()
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/odoo/src/odoo/addons/account/models/ir_attachment.py", line 159, in _unwrap_edi_attachments
    if supported_format['check'](attachment):
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/odoo/src/odoo/addons/account/models/ir_attachment.py", line 120, in is_xml
    is_text_plain_xml = 'text/plain' in attachment.mimetype and (guess_mimetype(attachment.raw).endswith('/xml') or attachment.name.endswith('.xml'))
                                                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/odoo/src/odoo/odoo/tools/mimetypes.py", line 205, in guess_mimetype
    mimetype = _guesser(bin_data[:MIMETYPE_HEAD_SIZE])
                        ~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
TypeError: 'bool' object is not subscriptable

The above server error caused the following client error:
RPC_ERROR: Odoo Server Error
    RPC_ERROR
        at makeErrorFromResponse (https://c4a8.odoo.com/web/assets/4f873cc/web.assets_web.min.js:3178:165)
        at XMLHttpRequest.<anonymous> (https://c4a8.odoo.com/web/assets/4f873cc/web.assets_web.min.js:3184:13)

[OCA-git-bot]

Hi @lmignon,
some modules you are maintaining are being modified, check this out!