[package:intl] All DateFormat constructors require locale to be a nullable string

[Adair-GA]

DateFormat constructors now require the locale argument to be a nullable string. Before, if the argument was not a String?, an exception would be thrown (see #14)

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• I’ve reviewed the contributor guide and applied the relevant portions to this PR.

[gemini-code-assist]

Summary of Changes

Hello @Adair-GA, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request refines the DateFormat constructors within the intl package by explicitly typing the locale argument as a nullable string (String?). This change addresses a previous behavior where passing a non-String? argument would result in an exception, thereby enhancing the robustness and predictability of the API by aligning it with expected null-safe practices.

Highlights

• Type Safety & API Consistency: All DateFormat constructors have been updated to explicitly type the locale parameter as String?, ensuring that the argument can be a nullable string without throwing an exception.

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[gemini-code-assist]

Code Review

This pull request correctly updates the named constructors of DateFormat to explicitly type the optional locale parameter as String?. This is a valuable improvement for type safety and aligns with modern Dart practices, especially with null safety. The changes are consistent and well-executed across all relevant constructors. I have no further suggestions, great work!

[github-actions]

Package publishing

Package	Version	Status	Publish tag (post-merge)
package:intl	0.20.3-wip	WIP (no publish necessary)
package:intl4x	0.13.0	ready to publish	intl4x-v0.13.0
package:intl_translation	0.20.1	already published at pub.dev
package:messages_shrinker	0.2.2-wip	WIP (no publish necessary)

Documentation at https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.

[github-actions]

PR Health

Breaking changes ⚠️

Package	Change	Current Version	New Version	Needed Version	Looking good?
intl	Breaking	0.20.2	0.20.3-wip	0.21.0 Got "0.20.3-wip" expected >= "0.21.0" (breaking changes)	⚠️

This check can be disabled by tagging the PR with skip-breaking-check.

Changelog Entry ✔️

Package	Changed Files

Changes to files need to be accounted for in their respective changelogs.

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Coverage ✔️

File	Coverage
pkgs/intl/lib/src/intl/date_format.dart	💚 66 %

This check for test coverage is informational (issues shown here will not fail the PR).

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API leaks ⚠️

The following packages contain symbols visible in the public API, but not exported by the library. Export these symbols or remove them from your publicly visible API.

Package	Leaked API symbol	Leaking sources
intl	StringStack	intl/date_format.dart::_DateFormatField::parse::input intl/date_format.dart::_DateFormatField::parseLoose::input intl/date_format.dart::_DateFormatField::parseLiteral::input intl/date_format.dart::_DateFormatField::parseLiteralLoose::input intl/date_format.dart::_DateFormatField::throwFormatException::stack intl/number_parser_base.dart::NumberParserBase::input intl/number_parser_base.dart::NumberParserBase::parseNumber::input
intl	DateBuilder	intl/date_format.dart::_DateFormatField::parse::dateFields intl/date_format.dart::_DateFormatField::parseLoose::dateFields

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License Headers ✔️

// Copyright (c) 2025, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

Files
no missing headers

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[mosuem]

You can ignore the API leaks, that can be fixed in a different PR and not caused by this. For the version, I don't believe this is breaking as the underlying constructor redirection does take a String? - so those would have thrown before as well.

So a changelog entry and you are good to go!

[Adair-GA]

Is it good like that or do I need to change anything?

[mosuem]

All good - I will start merging, which is a bit of a complicated process for this package, as the source-of-truth is inside Google. So please be patient :)