gh-130230: Fix crash in pow() with only Decimal third argument

[serhiy-storchaka]

• Issue: Issues with Decimal and three-argument pow() #130230

[skirpichev]

CC @kumaraditya303

[miss-islington-app]

Thanks @serhiy-storchaka for the PR 🌮🎉.. I'm working now to backport this PR to: 3.13.
🐍🍒⛏🤖

[bedevere-app]

GH-130246 is a backport of this pull request to the 3.13 branch.

[bedevere-app]

GH-130247 is a backport of this pull request to the 3.12 branch.

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot iOS ARM64 Simulator 3.x has failed when building commit b93b7e5.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/1380/builds/2619) and take a look at the build logs.
4. Check if the failure is related to this commit (b93b7e5) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/1380/builds/2619

Failed tests:

• test__colorize

Failed subtests:

• test_colorized_detection_checks_for_file - test.test__colorize.TestColorizeFunction.test_colorized_detection_checks_for_file
• test_colorized_detection_checks_for_std_streams - test.test__colorize.TestColorizeFunction.test_colorized_detection_checks_for_std_streams
• test_colorized_detection_checks_for_environment_variables - test.test__colorize.TestColorizeFunction.test_colorized_detection_checks_for_environment_variables

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File "/Users/buildbot/Library/Developer/XCTestDevices/B1B1F05B-F9F5-49CF-A120-389D86D49970/data/Containers/Bundle/Application/60E18174-C026-43AB-A88B-EFAD4D4FE247/iOSTestbed.app/python/lib/python3.14/test/test__colorize.py", line 33, in check
    self.assertEqual(_colorize.can_colorize(), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: False != True


Traceback (most recent call last):
  File "/Users/buildbot/Library/Developer/XCTestDevices/B1B1F05B-F9F5-49CF-A120-389D86D49970/data/Containers/Bundle/Application/60E18174-C026-43AB-A88B-EFAD4D4FE247/iOSTestbed.app/python/lib/python3.14/test/test__colorize.py", line 101, in test_colorized_detection_checks_for_std_streams
    self.assertEqual(_colorize.can_colorize(), True)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: False != True


Traceback (most recent call last):
  File "/Users/buildbot/Library/Developer/XCTestDevices/B1B1F05B-F9F5-49CF-A120-389D86D49970/data/Containers/Bundle/Application/60E18174-C026-43AB-A88B-EFAD4D4FE247/iOSTestbed.app/python/lib/python3.14/test/test__colorize.py", line 114, in test_colorized_detection_checks_for_file
    self.assertEqual(_colorize.can_colorize(file=file), True)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: False != True