From 747dd2074991d3f2e3fa5b24db1040c2649b896c Mon Sep 17 00:00:00 2001
From: Friday <aifriday700@gmail.com>
Date: Tue, 17 Feb 2026 12:39:34 +0000
Subject: [PATCH] Fix callable flag_value being instantiated when used as
 default

When `default=True` is set on a flag option with a callable `flag_value`
(e.g. a class), the `default=True` alignment code replaces the default
with the flag_value. Then `get_default()` sees `callable(value)` is True
and calls it, instantiating the class instead of returning it as-is.

Track when the default was set from the flag_value alignment and skip
the callable check in that case.

Fixes #3121

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 src/click/core.py     | 33 +++++++++++++++++++++++++++++++++
 tests/test_options.py |  4 ++--
 2 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/src/click/core.py b/src/click/core.py
index 6adc65ccd6..9485afa38e 100644
--- a/src/click/core.py
+++ b/src/click/core.py
@@ -2820,8 +2820,10 @@ def __init__(
         # and a flag_value set to something else. Refs:
         # https://github.com/pallets/click/issues/3024#issuecomment-3146199461
         # https://github.com/pallets/click/pull/3030/commits/06847da
+        self._default_from_flag_value = False
         if self.default is True and self.flag_value is not UNSET:
             self.default = self.flag_value
+            self._default_from_flag_value = True
 
         # Set the default flag_value if it is not set.
         if self.flag_value is UNSET:
@@ -2885,6 +2887,37 @@ def to_info_dict(self) -> dict[str, t.Any]:
         )
         return info_dict
 
+    @t.overload
+    def get_default(
+        self, ctx: Context, call: t.Literal[True] = True
+    ) -> t.Any | None: ...
+
+    @t.overload
+    def get_default(
+        self, ctx: Context, call: bool = ...
+    ) -> t.Any | t.Callable[[], t.Any] | None: ...
+
+    def get_default(
+        self, ctx: Context, call: bool = True
+    ) -> t.Any | t.Callable[[], t.Any] | None:
+        value = ctx.lookup_default(self.name, call=False)  # type: ignore
+
+        if value is UNSET:
+            value = self.default
+
+        # Don't call the default if it was set from the flag_value via
+        # the ``default=True`` alignment.  A callable flag_value (e.g. a
+        # class used as a flag value) should be returned as-is, not
+        # instantiated.  See https://github.com/pallets/click/issues/3121
+        if (
+            call
+            and callable(value)
+            and not self._default_from_flag_value
+        ):
+            value = value()
+
+        return value
+
     def get_error_hint(self, ctx: Context) -> str:
         result = super().get_error_hint(ctx)
         if self.show_envvar and self.envvar is not None:
diff --git a/tests/test_options.py b/tests/test_options.py
index f198d10183..e2c473bba8 100644
--- a/tests/test_options.py
+++ b/tests/test_options.py
@@ -2148,7 +2148,7 @@ def scan(pro):
             {"flag_value": Class1, "default": True},
             {"flag_value": Class2},
             [],
-            re.compile(r"'<test_options.Class1 object at 0x[0-9A-Fa-f]+>'"),
+            "<class 'test_options.Class1'>",
         ),
         (
             {"flag_value": Class1, "default": True},
@@ -2170,7 +2170,7 @@ def scan(pro):
             {"flag_value": Class1, "type": UNPROCESSED, "default": True},
             {"flag_value": Class2, "type": UNPROCESSED},
             [],
-            re.compile(r"<test_options.Class1 object at 0x[0-9A-Fa-f]+>"),
+            Class1,
         ),
         (
             {"flag_value": Class1, "type": UNPROCESSED, "default": True},