Rename compression WindowLog APIs to WindowLog2

[Copilot]

Based on a feedback from #128456 (comment)

Renames compression option APIs that exposed WindowLog so the public surface consistently uses WindowLog2 for base-2 log values, including the matching Zstandard decompression property MaxWindowLog2.

• API surface

  • BrotliCompressionOptions.WindowLog → WindowLog2
  • ZLibCompressionOptions.WindowLog → WindowLog2
  • ZstandardCompressionOptions.WindowLog → WindowLog2
  • ZstandardDecompressionOptions.MaxWindowLog → MaxWindowLog2
  • Aligns related public members to the same naming:
    • zlib/zstd DefaultWindowLog*, MinWindowLog*, MaxWindowLog* → *WindowLog2
    • encoder / decoder parameter names windowLog / maxWindowLog → windowLog2 / maxWindowLog2

• Implementation updates

  • Updates all in-repo call sites, option consumers, constructors, ref files, platform stubs, XML docs, and error text.
  • Ensures thrown ArgumentOutOfRangeException.ParamName values match the renamed public parameters.

• Compatibility

  • This is an intentional public API rename; no compatibility alias/shim is added.

• Example

  var options = new ZstandardCompressionOptions
  {
      Quality = 3,
      WindowLog2 = 20
  };
  
  var decompressionOptions = new ZstandardDecompressionOptions
  {
      MaxWindowLog2 = 20
  };

• Validation

  • Rebuilt System.IO.Compression and System.IO.Compression.Brotli
  • Ran targeted test projects:
    • System.IO.Compression.Tests
    • System.IO.Compression.Brotli.Tests

[rzikm]

@copilot Don't add string paramName parameters, but rename the existing parameters.

[Copilot]

@copilot Don't add string paramName parameters, but rename the existing parameters.

Addressed in e2c1640.

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[rzikm]

@copilot you missed two places

[Copilot]

@copilot you missed two places

Fixed in a9dd414.

[Copilot]

Pull request overview

Renames the WindowLog / MaxWindowLog public-facing compression option members and related parameter names to *WindowLog2 / *MaxWindowLog2 to make the base-2 logarithm semantics explicit and consistent across Brotli, zlib/deflate/gzip, and Zstandard APIs.

Changes:

• Renames public option properties and related helpers/constants to *WindowLog2 (and Zstd decompression MaxWindowLog2), including ref assembly updates.
• Updates encoder/decoder constructors, parameter validation (ArgumentOutOfRangeException.ParamName), and call sites to use the new parameter names.
• Updates tests and user-facing error text to match the new naming.

Reviewed changes

Copilot reviewed 24 out of 24 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/libraries/System.IO.Compression/tests/Zstandard/ZstandardEncoderDecoderTests.cs	Updates Zstd encoder/decoder tests for renamed ctor parameters and messages.
src/libraries/System.IO.Compression/tests/Zstandard/ZstandardCompressionOptionsTests.cs	Updates Zstd options tests to WindowLog2 / MaxWindowLog2.
src/libraries/System.IO.Compression/tests/ZLibEncoderDecoderTestBase.cs	Aligns shared zlib test base to expect windowLog2 param name.
src/libraries/System.IO.Compression/tests/ZLibCompressionOptionsUnitTests.cs	Renames zlib options tests for WindowLog2 and *WindowLog2 statics.
src/libraries/System.IO.Compression/src/System/IO/Compression/Zstandard/ZstandardEncoder.cs	Renames Zstd encoder ctors/overloads and validation to windowLog2.
src/libraries/System.IO.Compression/src/System/IO/Compression/Zstandard/ZstandardDecompressionOptions.cs	Renames and validates decompression option MaxWindowLog2.
src/libraries/System.IO.Compression/src/System/IO/Compression/Zstandard/ZstandardDecoder.cs	Renames Zstd decoder ctors/validation to maxWindowLog2.
src/libraries/System.IO.Compression/src/System/IO/Compression/Zstandard/ZstandardCompressionOptions.cs	Renames Zstd compression option WindowLog2 and related statics/docs.
src/libraries/System.IO.Compression/src/System/IO/Compression/Zstandard/Zstandard.PlatformNotSupported.cs	Updates platform stub members/ctors to *WindowLog2 naming.
src/libraries/System.IO.Compression/src/System/IO/Compression/ZLibStream.cs	Uses ZLibCompressionOptions.WindowLog2 when resolving window bits.
src/libraries/System.IO.Compression/src/System/IO/Compression/ZLibEncoder.cs	Renames zlib encoder ctor/overload parameter to windowLog2.
src/libraries/System.IO.Compression/src/System/IO/Compression/ZLibCompressionOptions.cs	Renames zlib options property/fields/statics to *WindowLog2.
src/libraries/System.IO.Compression/src/System/IO/Compression/GZipStream.cs	Uses ZLibCompressionOptions.WindowLog2 when resolving window bits.
src/libraries/System.IO.Compression/src/System/IO/Compression/GZipEncoder.cs	Renames gzip encoder ctor/overload parameter to windowLog2.
src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateZLib/DeflateStream.cs	Uses ZLibCompressionOptions.WindowLog2 when resolving window bits.
src/libraries/System.IO.Compression/src/System/IO/Compression/DeflateEncoder.cs	Renames deflate encoder ctors/overloads and validation to windowLog2.
src/libraries/System.IO.Compression/src/Resources/Strings.resx	Updates the Zstd “window too large” guidance text to maxWindowLog2.
src/libraries/System.IO.Compression/ref/System.IO.Compression.cs	Updates public ref surface for renamed members/parameters (*WindowLog2).
src/libraries/System.IO.Compression.Brotli/tests/CompressionStreamUnitTests.Brotli.cs	Updates Brotli options tests to WindowLog2.
src/libraries/System.IO.Compression.Brotli/src/System/IO/Compression/enc/BrotliStream.Compress.cs	Uses BrotliCompressionOptions.WindowLog2 when configuring encoder.
src/libraries/System.IO.Compression.Brotli/src/System/IO/Compression/enc/BrotliCompressionOptions.cs	Renames Brotli options property/field to WindowLog2.
src/libraries/System.IO.Compression.Brotli/ref/System.IO.Compression.Brotli.cs	Updates Brotli ref surface to expose WindowLog2.
src/libraries/Common/tests/System/IO/Compression/EncoderDecoderTestBase.cs	Aligns shared encoder/decoder test expectations to windowLog2 naming.
src/libraries/Common/tests/System/IO/Compression/CompressionStreamUnitTestBase.cs	Updates shared stream roundtrip test name and option property to WindowLog2.

[iremyux]

I understand how WindowLog can be confusing, at the same time I am not a big fan of WindowLog2. But I guess WindowLog2 is better.