[FIX] base_import_module: restore module icon

The revision dd3f918c
introduced a regression:
it was no longer possible to set an icon in the import module,
and if no icon is provided,
the icon should fall back to the base module icon,
which wasn't the case either.

In this last case, it even leaded to a crash:
```
File "/home/odoo/src/14.0/odoo/odoo/addons/base/models/ir_module.py", line 251, in _get_icon_image
    with tools.file_open(path, 'rb') as image_file:
  File "/home/odoo/src/14.0/odoo/odoo/tools/misc.py", line 176, in file_open
    return _fileopen(name, mode=mode, basedir=base, pathinfo=pathinfo, basename=basename, filter_ext=filter_ext)
  File "/home/odoo/src/14.0/odoo/odoo/tools/misc.py", line 211, in _fileopen
    raise ValueError("Unknown path: %s" % name)
Exception
ValueError: Unknown path: /base/static/description/icon.png
```

opw-3340652

closes odoo/odoo#124307

Signed-off-by: Denis Ledoux (dle) <dle@odoo.com>

addons/base_import_module/models/ir_module.py

@@ -58,6 +58,10 @@ class IrModule(models.Model):
                 terp.update(ast.literal_eval(f.read().decode()))
         if not terp:
             return False
+        if not terp.get('icon'):
+            icon_path = 'static/description/icon.png'
+            module_icon = module if os.path.exists(opj(path, icon_path)) else 'base'
+            terp['icon'] = opj('/', module_icon, icon_path)
         values = self.get_values_from_terp(terp)
         if 'version' in terp:
             values['latest_version'] = terp['version']

addons/base_import_module/tests/test_import_module.py

@@ -10,7 +10,7 @@ from unittest.mock import patch
 
 from odoo.addons import __path__ as __addons_path__
 from odoo.tools import mute_logger
-from odoo.tests.common import TransactionCase
+from odoo.tests.common import TransactionCase, HttpCase
 
 class TestImportModule(TransactionCase):
     def import_zipfile(self, files):
@@ -189,3 +189,20 @@ class TestImportModule(TransactionCase):
         static_attachment = self.env['ir.attachment'].search([('url', '=', '/%s' % static_path)])
         self.assertEqual(static_attachment.name, os.path.basename(static_path))
         self.assertEqual(static_attachment.datas, base64.b64encode(static_data))
+
+
+class TestImportModuleHttp(TestImportModule, HttpCase):
+    def test_import_module_icon(self):
+        """Assert import a module with an icon result in the module displaying the icon in the apps menu,
+        and with the base module icon if module without icon"""
+        files = [
+            ('foo/__manifest__.py', b"{'name': 'foo'}"),
+            ('foo/static/description/icon.png', b"foo_icon"),
+            ('bar/__manifest__.py', b"{'name': 'bar'}"),
+        ]
+        self.import_zipfile(files)
+        foo_icon_path, foo_icon_data = files[1]
+        # Assert icon of module foo, which must be the icon provided in the zip
+        self.assertEqual(self.url_open('/' + foo_icon_path).content, foo_icon_data)
+        # Assert icon of module bar, which must be the icon of the base module as none was provided
+        self.assertEqual(self.env.ref('base.module_bar').icon_image, self.env.ref('base.module_base').icon_image)