Defines three security groups: Fusion Accounting User / Manager / Administrator
Auto-promotes Odoo account.group_account_user -> Fusion User and account.group_account_manager -> Fusion Admin
Declares schema-preservation fields on account.move and account.reconcile.model so that Enterprise extension fields (deferred revenue links, signing user, etc.) survive an Enterprise uninstall
Exposes the helper env['ir.module.module']._fusion_is_enterprise_accounting_installed()

Install

This module never installs alone. Install fusion_accounting (the meta-module) or any of the feature sub-modules — they all depend on fusion_accounting_core.

Uninstall

Uninstalling fusion_accounting_core will remove the security groups and the schema-preservation fields. If Enterprise is also installed, uninstalling fusion_accounting_core will cause Odoo to consider the deferred / signing fields owned only by Enterprise — which is the original Enterprise-only state (no data loss, just back to Enterprise-controlled schema).

Troubleshooting

If users are missing the "Fusion Accounting" privilege section in user settings after install, the implied_ids mechanism only fires for newly-added users. Backfill existing users via SQL:

INSERT INTO res_groups_users_rel (gid, uid)
SELECT g.res_id, gu.uid
FROM res_groups_users_rel gu
JOIN ir_model_data g ON g.module = 'fusion_accounting_core' AND g.name = 'group_fusion_accounting_user'
JOIN ir_model_data ag ON ag.module = 'account' AND ag.name = 'group_account_user' AND gu.gid = ag.res_id
ON CONFLICT DO NOTHING;