[libcxx-commits] [libcxx] [libc++] Add a release note about multi{map, set}::find not returning the first element anymore (PR #155252)

[via libcxx-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libcxx

Author: Nikolas Klauser (philnik777)

<details>
<summary>Changes</summary>

We've modified the algorithm of `__tree::find` in #<!-- -->152370, which can change the return value. Since we're always returned the lower bound before some users started relying on it. This patch adds a release note so users are aware that this might break their code.



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Full diff: https://github.com/llvm/llvm-project/pull/155252.diff


1 Files Affected:

- (modified) libcxx/docs/ReleaseNotes/22.rst (+4) 


``````````diff
diff --git a/libcxx/docs/ReleaseNotes/22.rst b/libcxx/docs/ReleaseNotes/22.rst
index a26c5476d421b..6be269cfbbc84 100644
--- a/libcxx/docs/ReleaseNotes/22.rst
+++ b/libcxx/docs/ReleaseNotes/22.rst
@@ -61,6 +61,10 @@ Deprecations and Removals
 Potentially breaking changes
 ----------------------------
 
+- The algorithm for ``multi{map,set}::find`` has been modified, which doesn't guarantee that the first element is
+  returned. If code relies on the first element being returned from ``find`` it may be broken. To fix it use
+  ``lower_bound`` or ``equal_range`` instead.
+
 Announcements About Future Releases
 -----------------------------------
 

``````````

</details>


https://github.com/llvm/llvm-project/pull/155252