3.4.0

What's New 📣

This release notably adds nullable reference type annotations (see #582 and #803), the two experimental operators below and fixes a few bugs:

• Merge (experimental)
• Batch overloads using an array pool (experimental)

Breaking Changes ⚠️

While there are no breaking API changes in this release, the following changes will affect users using on .NET versions that have reached end-of-life:

• Use .NET 6 SDK while dropping .NET 5 & Core 2.1 by @atifaziz in #843
• Updated .NET Framework target to 4.6.2 by @atifaziz in #934

See Also ℹ️

• 3.4.0 milestone for changes in this release
• Commit history since 3.3.2

New Contributors 👋🏽

• @TAGC made their first contribution in #772
• @MarcDirven made their first contribution in #796
• @sid-6581 made their first contribution in #808
• @GitHubPang made their first contribution in #828
• @MateoMiller made their first contribution in #846
• @viceroypenguin made their first contribution in #888
• @leotsarev made their first contribution in #907
• @i3arnon made their first contribution in #959

What's Changed 🗒️

• OrderedMerge: add tests by @Orace in #736
• Replace explicit type mentions with object pattern by @atifaziz in #751
• Optimize Batch for empty IReadOnlyCollection<T> too by @leandromoh in #750
• Update to .NET Core SDK 3.1 by @atifaziz in #754
• Update .NET Core installation script by @atifaziz in #756
• Interleave: Do not call GetEnumerator eagerly by @Orace in #730
• Fix (bash) test script to test against .NET Core 3.1 by @atifaziz in #757
• Update all test dependencies by @atifaziz in #755
• Deploy package only on CI build of "deploy" by @atifaziz in #758
• Fix bug in LastOrDefault for extrema sequence by @atifaziz in #761
• Annotate nullability of reference types by @atifaziz in #582 ⭐
• Fix return value docs for MinBy/MaxBy by @atifaziz in #765
• Fix .NET Core version in test script by @atifaziz in #767
• Update to .NET 5.0 SDK by @atifaziz in #766
• Fix duplicate test runs on Windows by @atifaziz in #769
• Fix typo in Partition return value documentation by @TAGC in #772
• Integrate templated code generation into project file by @atifaziz in #776
• Add .NET 5.0 as a test target by @atifaziz in #777
• Disable parallel building due to T4 for simplicity by @atifaziz in #779
• Unify to single CI platform by @atifaziz in #778
• Enable use of C# 9 across all projects by @atifaziz in #780
• Mask System.Linq for async streams by @atifaziz in #781
• Fix XML encoding of ">" in project file by @atifaziz in #785
• Simpler extensions generator with namespace & program class by @atifaziz in #787
• Replace using statements with declarations in tests by @atifaziz in #786
• Update test project dependencies to latest versions by @atifaziz in #790
• Fix grep invocation on Windows CI build by @atifaziz in #791
• Use consistent line-folding in CI YAML shell sections by @atifaziz in #792
• Doc update (+ instead of /) by @MarcDirven in #796
• Fix dictionary bug when null key has null value by @atifaziz in #800
• Fix TrySingle signature with honest nullable annotations by @atifaziz in #801
• Cleanup ! operator usage in FallbackIfEmpty by @sid-6581 in #808
• Fix Pad* signatures with more honest nullable annotations by @atifaziz in #804
• Fix Lag & Lead signatures with more honest nullable annotations by @atifaziz in #805
• Fix ReverseComparer signature with more honest nullable annotations by @sid-6581 in #807
• Fix GroupAdjacent null key handling bug by @atifaziz in #810
• Fix FullGroupJoin signature with more honest nullable annotations by @sid-6581 in #806
• Add test to ensure Batch does not reuse internal array by @leandromoh in #820
• Update links in README by @GitHubPang in #828
• Use .NET 6 SDK while dropping .NET 5 & Core 2.1 by @atifaziz in #843
• Removed unnecessary null check in Batch method by @MateoMiller in #846
• Fix code coverage with new collector by @atifaziz in #845
• Update referenced packages to latest versions by @atifaziz in #844
• Fix Flatten signature parts to be null-oblivious by @atifaziz in #847
• Add missing remarks tags on Batch overload by @atifaziz in #849
• Constrain key type param in ToDictionary to notnull by @atifaziz in #852
• Allow use of C# 10 by @atifaziz in #853
• Remove look-up optimizations in CountBy/ScanBy by @atifaziz in #855
• Replace Nullable with PolySharp by @atifaziz in #857
• Fix code coverage using latest coverlet collector by @atifaziz in #858
• Adjust library for .NET 6 target by @atifaziz in #860
• Use end index "[^1]" by @atifaziz in #862
• Use string interpolation by @atifaziz in #863
• Discard unused parameters by @atifaziz in #864
• Rewrite switch statements as expressions by @atifaziz in #865
• Use += to increment by @atifaziz in #869
• Convert using statements to declarations by @atifaziz in #867
• Revise & take advantage of pattern matching by @atifaziz in #866
• Rewrite swap more succinctly (via tuples) by @atifaziz in #868
• Simplify names (IDE0001) by @atifaziz in #861
• Make PolySharp a build-time dependency by @jnyrup in #870
• Update to .NET 7 by @atifaziz in #871
• Fix test scripts to test on .NET 7 runtime by @atifaziz in #873
• Allow use of C# 11 by @atifaziz in #874
• Replace MayBeNull with ? in IExtremaEnumerable members by @atifaziz in #872
• Enable nullable context in Flatten tests by @atifaziz in #875
• Update ReportGenerator tool to 5.1.11 by @atifaziz in #876
• Enable nullable context for extensions generator by @atifaziz in #878
• Sync Lookup + Grouping from .NET 7 sources by @atifaziz in #879
• Batch overloads using an array pool by @atifaziz in #856
• PartialSort: #nullable enable on tests by @viceroypenguin in #888
• Fix nullability annotation in Subject by @atifaziz in #891
• Replace null-forgiving operator uses with debug assertions by @atifaziz in #890
• Update Memoize documentation by @viceroypenguin in #895
• Add parameter annotations for Partition by @viceroypenguin in #897
• Document Partition exceptions by @viceroypenguin in #886
• Add null check for Partition by @viceroypenguin in #896
• Rewrite switch in Memoize as expression by @viceroypenguin in #894
• Cleanup Partition Nullability by @viceroypenguin in #881
• Add exceptions section to Zip* docs by @viceroypenguin in #887
• Add identity method to reduce JIT-ing by @viceroypenguin in #880
• Use random shared by @leotsarev in #907
• Fix nullability for ZipLongest by @viceroypenguin in #900
• Enable nullable context for remaining *Zip* tests by @atifaziz in #908
• Add NUnit.Analyzers, addressing warnings by @atifaziz in #910
• Remove unused imports by @atifaziz in #911
• Update all tests to consistently use the NUnit constraint model by @atifaziz in #912
• Fix nullability of Rank comparer argument by @atifaziz in #913
• Fix nullability of ToDataTable expressions argument by @atifaziz in #914
• Enable nullable context for entire solution by @atifaziz in #915
• Seal private enumerators by @atifaziz in #916
• Replace ! with debug assertion in Permutations by @atifaziz in #917
• Fix typos in comments by @atifaziz in #918
• Use LinkedList in Interleave to avoid many null checks by @Orace in #726
• Update packages to latest versions by @atifaziz in #920
• Add more Interleave tests by @Orace in #728
• Retire our delegating Comparer by @atifaziz in #921
• Mark local function static where possible by @atifaziz in #922
• Address to-do about consolidating testing sequence implementations by @atifaziz in #923
• Use tuples to perform swap in Permutations by @atifaziz in #925
• Fix exception thrown by current buffer index implementation by @atifaziz in #927
• Rewrite next permutation while-loop into a for-loop by @atifaziz in #926
• Consolidate error formatting between AssertCount and Fold by @atifaziz in #929
• Enable default compile items in test project by @atifaziz in #930
• Enable static analysis by @atifaziz in #924
• Additional tests for TagFirstLast by @Orace in #928
• Fix off-by-one index validation bug in ToArrayByIndex by @atifaziz in #932
• Decompose TagFirstLast implementation for speed by @Orace in #643
• Updated .NET Framework target to 4.6.2 by @atifaziz in #934
• Remove redundant type spec on obvious new expressions by @atifaziz in #935
• Use testing sequence in Pairwise test by @atifaziz in #937
• Declare & set modifier preference (IDE0040) severity by @atifaziz in #938
• Fix Exclude to not call MoveNext past end of sequence by @Orace in #692
• Fix home when setting path during CI build by @atifaziz in #941
• Revert integration of T4 code generation into project file by @atifaziz in #940
• Simplify tests for count family of methods by @Arithmomaniac in #507
• Improve list optimisation in CountDown by @atifaziz in #942
• Enforce and address code style issues by @atifaziz in #944
• List-like union as struct to save allocation + virtual dispatch by @atifaziz in #472
• Fix collection-optimized paths to be at iteration-time by @atifaziz in #946
• Rename read-only list/collection field of ListLike/CollectionLike by @atifaziz in #948
• Improve and Validate TestingSequence assertions by @viceroypenguin in #936
• Consolidate structural differences in *Like types by @atifaziz in #949
• Revoke (obsolete) disabling of parallel builds by @atifaziz in #950
• Run T4 templates if targets are out-of-date by @atifaziz in #953
• Discard unused expression value (IDE0058) by @atifaziz in #954
• Remove testing on .NET Core 3.1 that's no longer supported by @atifaziz in #955
• Dynamically discover/build glob for ECLint by @atifaziz in #957
• Separate build pre-/post-validation into relevant CI sections by @atifaziz in #952
• Fix some doc comments by @atifaziz in #958
• Make use of message in Debug.Assert by @i3arnon in #959
• Use compiler-generated delegate caches in ToDelimitedString by @atifaziz in #966
• Merge sequence of async streams into single async stream by @atifaziz in #793 ⭐
• Update .NET SDK to 7.0.200 by @atifaziz in #967
• Fix collection-optimized paths for Batch by @viceroypenguin in #965
• Simplify Fold Implementation by @viceroypenguin in #961
• Fix inconsistencies in Fold doc by @atifaziz in #968
• Add read-me document to NuGet package by @atifaziz in #970
• Implement Fold entirely in its own terms by @atifaziz in #969
• Remove unused imports (in ToDelimitedString) by @atifaziz in #971
• Use compiler-generated delegate cache in AssertCount by @atifaziz in #972
• Validate package by @atifaziz in #974
• Produce deterministic CI builds by @atifaziz in #975