[IMP] server_environment: module uninstallation

server_environment/README.rst

@@ -1,7 +1,3 @@
-.. image:: https://odoo-community.org/readme-banner-image
-   :target: https://odoo-community.org/get-involved?utm_source=readme
-   :alt: Odoo Community Association
-
 ======================================
 server configuration environment files
 ======================================
@@ -17,7 +13,7 @@ server configuration environment files
 .. |badge1| image:: https://img.shields.io/badge/maturity-Production%2FStable-green.png
     :target: https://odoo-community.org/page/development-status
     :alt: Production/Stable
-.. |badge2| image:: https://img.shields.io/badge/license-LGPL--3-blue.png
+.. |badge2| image:: https://img.shields.io/badge/licence-LGPL--3-blue.png
     :target: http://www.gnu.org/licenses/lgpl-3.0-standalone.html
     :alt: License: LGPL-3
 .. |badge3| image:: https://img.shields.io/badge/github-OCA%2Fserver--env-lightgray.png?logo=github
@@ -100,19 +96,19 @@ You can edit the settings you need in the ``server_environment_files``
 addon. The ``server_environment_files_sample`` can be used as an
 example:
 
-- values common to all / most environments can be stored in the
-  ``default/`` directory using the .ini file syntax;
-- each environment you need to define is stored in its own directory and
-  can override or extend default values;
-- you can override or extend values in the main configuration file of
-  your instance;
-- In some platforms (like odoo.sh where production config file is copied
-  to staging) it can be useful to overwrite options written in the
-  ``[options]`` section. You must allow the override by adding
-  ``server_environment_allow_overwrite_options_section = True`` to the
-  former ``odoo.cfg`` config file or through the environment variable:
-  ``export SERVER_ENVIRONMENT_ALLOW_OVERWRITE_OPTIONS_SECTION=True`` (if
-  both are set config file takes precedence).
+-  values common to all / most environments can be stored in the
+   ``default/`` directory using the .ini file syntax;
+-  each environment you need to define is stored in its own directory
+   and can override or extend default values;
+-  you can override or extend values in the main configuration file of
+   your instance;
+-  In some platforms (like odoo.sh where production config file is
+   copied to staging) it can be useful to overwrite options written in
+   the ``[options]`` section. You must allow the override by adding
+   ``server_environment_allow_overwrite_options_section = True`` to the
+   former ``odoo.cfg`` config file or through the environment variable:
+   ``export SERVER_ENVIRONMENT_ALLOW_OVERWRITE_OPTIONS_SECTION=True``
+   (if both are set config file takes precedence).
 
 Environment variable
 --------------------
@@ -221,16 +217,176 @@ If you want to have a technical name to reference:
 
        [...]
 
+Restoring columns on uninstall
+------------------------------
+
+When ``server.env.mixin`` is bound to an existing model, the ORM drops
+the original stored columns for all env-managed fields. If the binding
+addon is later uninstalled, those columns must be recreated so the
+database remains usable.
+
+Add an ``uninstall_hook`` to your addon and delegate to
+``restore_env_managed_columns``:
+
+::
+
+   # your_addon/__init__.py
+   from . import models
+
+   def uninstall_hook(env):
+       env["server.env.mixin"].restore_env_managed_columns(
+           "storage.backend",
+           ["directory_path", "other_field"],
+       )
+
+   # your_addon/__manifest__.py
+   {
+       ...
+       "uninstall_hook": "uninstall_hook",
+   }
+
+The helper creates any missing columns (idempotent: safe to call
+multiple times) and repopulates them with each record's current
+effective value — whether that value came from an environment
+configuration file or from the stored default field
+(``x_<field>_env_default``).
+
+The hook must run *before* the ORM extensions are removed, which is
+guaranteed by Odoo's uninstall sequence (hooks execute before
+``Module.module_uninstall()``).
+
+Handling required fields
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+If a restored column is **required** (has a ``NOT NULL`` constraint) but
+has no effective value (missing from environment config and no default
+field set), the restoration will fail with a ``UserError``.
+
+**Solution:** pass a ``field_defaults`` dictionary with fallback values:
+
+::
+
+   def uninstall_hook(env):
+       env["server.env.mixin"].restore_env_managed_columns(
+           "ir.mail_server",
+           ["smtp_host", "smtp_authentication"],
+           field_defaults={
+               "smtp_authentication": "login",  # fallback for required field
+           },
+       )
+
+The helper will use the fallback value if provided and the computed
+field value is empty. If no fallback is provided but a required field
+has no value, a ``UserError`` is raised with instructions on how to
+provide a ``field_defaults`` parameter.
+
+Migrating when dropping server_environment dependency
+-----------------------------------------------------
+
+When refactoring an existing addon that embeds a ``server.env.mixin``
+binding, you may want to extract the binding into a separate *glue*
+addon and drop the ``server_environment`` dependency from the original.
+This keeps the base addon lightweight while preserving
+server-environment features for those who install the glue addon.
+
+**Pattern:**
+
+-  **Original addon (v1)**: depends on ``server_environment`` and binds
+   the mixin directly in model code.
+-  **Refactored addon (v2)**: removes ``server_environment`` from
+   dependencies, removes the mixin binding and the related ORM model
+   inheritance.
+-  **New glue addon** (optional, same version): depends on both
+   ``server_environment`` and the original addon v2; re-adds the mixin
+   binding in a separate module file.
+
+**Migration checklist:**
+
+1. In the **original addon's v2 ``__manifest__.py``**:
+
+   -  Remove ``"server_environment"`` from ``depends``.
+   -  Remove the model file(s) that contained the mixin binding.
+   -  Update ``depends`` to add the new glue addon *if* the base addon
+      still needs it (otherwise, make the glue addon optional for users
+      who want env-binding).
+
+2. In the **original addon's v2 model code**:
+
+   -  Delete or simplify the model class that inherited from
+      ``server.env.mixin``.
+   -  If the model was only there for the binding, remove it entirely.
+   -  Restore the original field definitions (not as computed fields).
+
+3. **Create a migration script** (if needed) to restore columns *during
+   the addon upgrade*, before the ORM model extensions are unloaded. Use
+   a ``@post_load`` hook or a dedicated migration script:
+
+   ::
+
+      # migrations/18.0.1.0.0/post-restore-columns.py
+      def migrate(cr, version):
+          # Call the restoration logic while the v1 model is still active
+          env = odoo.api.Environment(cr, odoo.SUPERUSER_ID, {})
+          # If any field is required and may have no value in the environment,
+          # provide a fallback via field_defaults
+          env["server.env.mixin"].restore_env_managed_columns(
+              "storage.backend",
+              ["directory_path", "other_field"],
+              field_defaults={
+                  "directory_path": "/tmp",  # fallback for required field
+              },
+          )
+
+4. **Create the glue addon** with the model re-inheritance:
+
+   ::
+
+      # your_addon_env/__init__.py
+      from . import models
+
+      # your_addon_env/models/__init__.py
+      from . import storage_backend
+
+      # your_addon_env/models/storage_backend.py
+      class StorageBackend(models.Model):
+          _name = "storage.backend"
+          _inherit = ["storage.backend", "server.env.mixin"]
+
+          @property
+          def _server_env_fields(self):
+              return {"directory_path": {}}
+
+      # your_addon_env/__manifest__.py
+      {
+          "name": "Storage Backend – Server Environment",
+          "version": "18.0.1.0.0",
+          "depends": ["server_environment", "storage_backend"],
+          "installable": True,
+      }
+
+**Key points:**
+
+-  Column restoration must happen *during the addon upgrade* (step 3),
+   not as an uninstall hook, because the original model binding is still
+   active.
+-  The ``restore_env_managed_columns`` helper is idempotent and safe to
+   call even if columns already exist.
+-  Users who do not need server environment features simply do *not*
+   install the glue addon—the base addon continues to work with plain
+   database columns.
+-  Users who do need server environment can install both the base addon
+   (v2+) and the glue addon (same version) to get the binding back.
+
 Known issues / Roadmap
 ======================
 
-- it is not possible to set the environment from the command line. A
-  configuration file must be used.
-- the module does not allow to set low level attributes such as database
-  server, etc.
-- server.env.techname.mixin's tech_name field could leverage the new
-  option for computable / writable fields and get rid of some onchange /
-  read / write code.
+-  it is not possible to set the environment from the command line. A
+   configuration file must be used.
+-  the module does not allow to set low level attributes such as
+   database server, etc.
+-  server.env.techname.mixin's tech_name field could leverage the new
+   option for computable / writable fields and get rid of some onchange
+   / read / write code.
 
 Bug Tracker
 ===========
@@ -253,18 +409,18 @@ Authors
 Contributors
 ------------
 
-- Florent Xicluna (Wingo) <florent.xicluna@gmail.com>
-- Nicolas Bessi <nicolas.bessi@camptocamp.com>
-- Alexandre Fayolle <alexandre.fayolle@camptocamp.com>
-- Daniel Reis <dgreis@sapo.pt>
-- Holger Brunn <hbrunn@therp.nl>
-- Leonardo Pistone <leonardo.pistone@camptocamp.com>
-- Adrien Peiffer <adrien.peiffer@acsone.com>
-- Thierry Ducrest <thierry.ducrest@camptocamp.com>
-- Guewen Baconnier <guewen.baconnier@camptocamp.com>
-- Thomas Binfeld <thomas.binsfeld@acsone.eu>
-- Stéphane Bidoul <stefane.bidoul@acsone.com>
-- Simone Orsi <simahawk@gmail.com>
+-  Florent Xicluna (Wingo) <florent.xicluna@gmail.com>
+-  Nicolas Bessi <nicolas.bessi@camptocamp.com>
+-  Alexandre Fayolle <alexandre.fayolle@camptocamp.com>
+-  Daniel Reis <dgreis@sapo.pt>
+-  Holger Brunn <hbrunn@therp.nl>
+-  Leonardo Pistone <leonardo.pistone@camptocamp.com>
+-  Adrien Peiffer <adrien.peiffer@acsone.com>
+-  Thierry Ducrest <thierry.ducrest@camptocamp.com>
+-  Guewen Baconnier <guewen.baconnier@camptocamp.com>
+-  Thomas Binfeld <thomas.binsfeld@acsone.eu>
+-  Stéphane Bidoul <stefane.bidoul@acsone.com>
+-  Simone Orsi <simahawk@gmail.com>
 
 Maintainers
 -----------

server_environment/models/server_env_mixin.py

@@ -7,7 +7,7 @@
 from lxml import etree
 
 from odoo import api, fields, models
-from odoo.tools import mute_logger
+from odoo.tools import SQL, mute_logger, sql
 
 from odoo.addons.base_sparse_field.models.fields import Serialized
 
@@ -428,3 +428,95 @@ def _setup_base(self):
             self._server_env_transform_field_to_read_from_env(field)
             self._server_env_add_is_editable_field(field)
         return
+
+    @api.model
+    def restore_env_managed_columns(self, model_name, field_names, field_defaults=None):
+        """Restore database columns for fields formerly managed via server.env.mixin.
+
+        When an addon binds ``server.env.mixin`` to an existing model, the ORM
+        drops the original stored columns.  Call this helper from an
+        ``uninstall_hook`` so those columns are recreated and repopulated
+        with their current effective values before the addon is removed.
+
+        The hook must run *while* the module's ORM extensions are still active
+        (guaranteed by Odoo's uninstall sequence: hooks execute before
+        ``Module.module_uninstall()``), so the env-computed fields are still
+        readable and their values can be written back to freshly created columns.
+
+        The operation is idempotent: calling it multiple times will not fail.
+
+        **Defaults:** If a restored field value is NULL/empty, the helper will
+        use the fallback from ``field_defaults`` (if provided) or the field's
+        ORM-level default (if defined).
+
+        Note: ``field.required`` is set to False by the mixin, so we cannot detect
+        which fields are required. Provide explicit ``field_defaults`` for fields
+        that must have values.
+
+        :param str model_name: dotted model name, e.g. ``"ir.mail_server"``
+        :param field_names: iterable of field names whose columns to restore
+        :param dict field_defaults: optional mapping of field name to fallback
+            value used when restoring a column that has no effective env-computed
+            value, e.g. ``{"smtp_authentication": "<login>"}``
+        """
+        model = self.env[model_name]
+        cr = self.env.cr
+        field_defaults = field_defaults or {}
+
+        for field_name in field_names:
+            field = model._fields.get(field_name)
+            if field is None:
+                _logger.warning(
+                    "restore_env_managed_columns: field %r not found on %s, skipping",
+                    field_name,
+                    model_name,
+                )
+                continue
+            column_type = field.column_type
+            if column_type is None:
+                _logger.warning(
+                    "restore_env_managed_columns: "
+                    "field %r on %s has no SQL column type, skipping",
+                    field_name,
+                    model_name,
+                )
+                continue
+            table = model._table
+            if not sql.column_exists(cr, table, field_name):
+                sql.create_column(cr, table, field_name, column_type[1], field.string)
+                _logger.info(
+                    "restore_env_managed_columns: created column %s.%s (%s)",
+                    table,
+                    field_name,
+                    column_type[1],
+                )
+            # Repopulate every existing record with the current computed value.
+            # The hook runs while the ORM extensions are still active, so the
+            # env-computed field is still readable via the normal accessor.
+            for record in model.search([]):
+                value = record[field_name]
+                # The ORM returns False for NULL on non-boolean fields; map
+                # that back to None so psycopg2 writes a proper SQL NULL.
+                if value is False and field.type != "boolean":
+                    value = None
+                elif value == "":
+                    value = None
+
+                # Try to get a default value if we have None.
+                # Note: field.required is False after mixin transformation,
+                # so we apply defaults for all None values when available.
+                if value is None:
+                    if field_name in field_defaults:
+                        value = field_defaults[field_name]
+                    elif field_name in model.default_get([field_name]):
+                        value = model.default_get([field_name])[field_name]
+
+                cr.execute(
+                    SQL(
+                        "UPDATE %s SET %s = %s WHERE id = %s",
+                        SQL.identifier(table),
+                        SQL.identifier(field_name),
+                        value,
+                        record.id,
+                    )
+                )