[fix] Result.defaults_from() inverted logic (#6019)

The bug was introduced in commit 8769b7c6d (typification of result items); this
patch fixes the bug and also addresses the peculiarity that fields can be set
but contain no *usable* value:

If a field is set (exists) but contains an empty string or the value ``None``,
it is also considered *not set*. This also ensures that an integer 0 is
evaluated *as set*!

Co-Authored: Markus Heiser <markus.heiser@darmarit.de>

searx/result_types/_base.py

@@ -32,7 +32,7 @@ import msgspec
 from searx import logger as log
 
 WHITESPACE_REGEX = re.compile('( |\t|\n)+', re.M | re.U)
-UNKNOWN = object()
+UNSET = object()
 
 
 def _normalize_url_fields(result: "Result | LegacyResult"):
@@ -326,12 +326,13 @@ class Result(msgspec.Struct, kw_only=True):
 
     def defaults_from(self, other: "Result"):
         """Fields not set in *self* will be updated from the field values of the
-        *other*.
+        *other*.  If a field is set (exists) but contains an empty string
+        or the value ``None``, it is also considered *not set*.
         """
         for field_name in self.__struct_fields__:
-            self_val = getattr(self, field_name, False)
-            other_val = getattr(other, field_name, False)
-            if self_val:
+            self_val = getattr(self, field_name, UNSET)
+            other_val = getattr(other, field_name, UNSET)
+            if self_val is UNSET and other_val not in (UNSET, "", None):
                 setattr(self, field_name, other_val)
 
 
@@ -440,8 +441,6 @@ class LegacyResult(dict[str, t.Any]):
        Do not use this class in your own implementations!
     """
 
-    UNSET: object = object()
-
     # emulate field types from type class Result
     url: str | None
     template: str
@@ -512,7 +511,7 @@ class LegacyResult(dict[str, t.Any]):
             )
 
     def __getattr__(self, name: str, default: t.Any = UNSET) -> t.Any:
-        if default == self.UNSET and name not in self:
+        if default == UNSET and name not in self:
             raise AttributeError(f"LegacyResult object has no field named: {name}")
         return self[name]
 
@@ -563,9 +562,12 @@ class LegacyResult(dict[str, t.Any]):
             self.engines.add(self.engine)
 
     def defaults_from(self, other: "LegacyResult"):
-        for k, v in other.items():
-            if not self.get(k):
-                self[k] = v
+        # If a field is set (exists) but contains an empty string or the value
+        # ``None``, it is also considered *not set*.
+        for field_name, other_val in other.items():
+            self_val = self.get(field_name, UNSET)
+            if self_val is UNSET and other_val not in ("", UNSET):
+                self[field_name] = other_val
 
     def filter_urls(self, filter_func: "Callable[[Result | LegacyResult, str, str], str | bool]"):
         """See :py:obj:`Result.filter_urls`"""

searx/translations/da/LC_MESSAGES/messages.po

@@ -20,7 +20,7 @@ msgstr ""
 "Project-Id-Version: searx\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
 "POT-Creation-Date: 2026-03-24 18:43+0000\n"
-"PO-Revision-Date: 2026-04-09 18:57+0000\n"
+"PO-Revision-Date: 2026-04-16 06:57+0000\n"
 "Last-Translator: AndersNordh <andersnordh@noreply.codeberg.org>\n"
 "Language-Team: Danish <https://translate.codeberg.org/projects/searxng/"
 "searxng/da/>\n"
@@ -29,7 +29,7 @@ msgstr ""
 "Content-Type: text/plain; charset=utf-8\n"
 "Content-Transfer-Encoding: 8bit\n"
 "Plural-Forms: nplurals=2; plural=n != 1;\n"
-"X-Generator: Weblate 5.16.2\n"
+"X-Generator: Weblate 5.17\n"
 "Generated-By: Babel 2.18.0\n"
 
 #. CONSTANT_NAMES['NO_SUBGROUPING']
@@ -885,7 +885,7 @@ msgstr "Indstillinger"
 
 #: searx/templates/simple/base.html:68
 msgid "Powered by"
-msgstr "Leveret af"
+msgstr "Drevet af"
 
 #: searx/templates/simple/base.html:68
 msgid "a privacy-respecting, open metasearch engine"

searx/translations/sv/LC_MESSAGES/messages.po

@@ -38,8 +38,8 @@ msgstr ""
 "Project-Id-Version: searx\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
 "POT-Creation-Date: 2026-03-24 18:43+0000\n"
-"PO-Revision-Date: 2026-03-27 07:33+0000\n"
-"Last-Translator: bittin <bittin@noreply.codeberg.org>\n"
+"PO-Revision-Date: 2026-04-16 06:57+0000\n"
+"Last-Translator: AndersNordh <andersnordh@noreply.codeberg.org>\n"
 "Language-Team: Swedish <https://translate.codeberg.org/projects/searxng/"
 "searxng/sv/>\n"
 "Language: sv\n"
@@ -47,7 +47,7 @@ msgstr ""
 "Content-Type: text/plain; charset=utf-8\n"
 "Content-Transfer-Encoding: 8bit\n"
 "Plural-Forms: nplurals=2; plural=n != 1;\n"
-"X-Generator: Weblate 5.16.2\n"
+"X-Generator: Weblate 5.17\n"
 "Generated-By: Babel 2.18.0\n"
 
 #. CONSTANT_NAMES['NO_SUBGROUPING']
@@ -903,7 +903,7 @@ msgstr "Inställningar"
 
 #: searx/templates/simple/base.html:68
 msgid "Powered by"
-msgstr "Drivet av"
+msgstr "Drivs av"
 
 #: searx/templates/simple/base.html:68
 msgid "a privacy-respecting, open metasearch engine"