[flaviolazzarini]

As of dotCover 2025.2 JetBrains made significant changes to the parameter syntax of dotCover. Some changes where already made in #4670. Unfortunately not all commands and parameters have been covered. This pull request adds compatibility for the following commands:

• merge
• report

analyse has not been covered, as it's not a supported command anymore.

For a complete list of the commands and their parameters see https://www.jetbrains.com/help/dotcover/dotCover__Console_Runner_Commands.html#help

This fixes #4096

[flaviolazzarini]

@microsoft-github-policy-service agree company="exanicAG"

[devlead]

The direction looks sound and aligns with #4670, but I found one blocking regression and some medium/minor things that should be fixed before merge.

Blocking

DotCoverReport ignores outputFile in new syntax (the default path)

With UseLegacySyntax = false (default), the 3-arg API Report(sourceFile, outputFile, settings) never passes outputFile to the CLI. GenerateArguments only emits --snapshot-source and optional JsonReportOutput / XmlReportOutput from settings.

This breaks the common call pattern:

DotCoverReport(source, new FilePath("./result.xml"), new DotCoverReportSettings());

Previously, this produced /Output=...; now it runs with no output path. The new-syntax tests always set OutputFile = null, so there's no coverage for the default fixture path with a non-null output file.

Suggested fix: When !UseLegacySyntax && outputFile != null, map to the appropriate new flag (e.g., --xml-report-output for default ReportType.XML, --json-report-output for ReportType.JSON). I'd also add a test for that path.

Medium

• Legacy filters are silently dropped on cover: Scope, Filters, AttributeFilters, ProcessFilters, and DisableDefaultFilters are ignored in the new syntax. Scripts using .WithFilter(...) without .WithLegacySyntax() will lose filters with no warning. I'd document this in the release notes and consider a runtime warning when legacy filter collections are populated, but UseLegacySyntax is false.
• HTML / DetailedXML / NDependXML are legacy-only: New report syntax only supports --json-report-output and --xml-report-output. The new DotCoverReport alias example still shows ReportType = HTML, which won't work without legacy syntax.

Minor

• DotCoverReportSettings: XmlReportOutput / XmlReportCoveringTestsScope XML comments say "JSON report" (looks like copy-paste).
• DotCoverReporter.Report(source, settings) XML doc says "Cover" instead of "Report".
• Test regions: typo "Paramter" → "Parameter".
• No DotCoverMerge alias for optional output (tool-level overload exists).
• analyse unchanged, fine with me if that's acknowledged and the command is deprecated in dotCover 2025.2+.

What looks good

• merge / report new syntax (--snapshot-source, --snapshot-output, --temporary-directory, --log-file) looks correct to me.
• Moving UseLegacySyntax to base DotCoverSettings makes sense.
• Lowercase command names match the 2025.2 convention.
• Good legacy vs new test split; build and unit tests pass locally on my machine.

Summary

Area	My take
merge	Good
report	Please fix outputFile regression
cover	OK, I'd document filter migration
Tests	Missing main report output case

[devlead]

Thanks for addressing the June review. The outputFile mapping, filter warnings, XML examples, comment typos, and merge-without-output overloads look good.

A few remaining items before merge:

Blocking

• analyse + LogFile: GetArguments now emits --log-file unless UseLegacySyntax is true. DotCoverAnalyse still always uses legacy /Target* /Output flags, so the default path mixes syntax. The analyser test was updated to set UseLegacySyntax = true rather than keeping analyse on /LogFile.
• Unsupported ReportType: HTML / DetailedXML / NDependXML silently map to --xml-report-output.
• Settings mutation: mapping outputFile writes into the caller's XmlReportOutput / JsonReportOutput.

Medium

• DotCoverMerge(sourceFiles, settings) is missing [CakeMethodAlias] (and the usual null checks), so Cake scripts will not see that overload.
• The new 2-arg report example uses DotCoverReportType.Xml (invalid; enum is XML).
• WithLegacySyntax() is still cover-only even though the flag now lives on DotCoverSettings.
• The existing DotCoverCover example still uses .WithFilter(...) without .WithLegacySyntax() or --exclude-assemblies, so it documents the drop-and-warn path.

Process

• CI on this PR is red (looks like the original June run). Please re-run after the follow-up.
• Please call out in release notes: default 2025.2 syntax, filter → --exclude-*, report types XML/JSON only, optional merge output, analyse remaining legacy-only.

merge / report new flags look correct against current JetBrains docs.

[flaviolazzarini]

@devlead thank you for the thorough review. I was finally able to make the requested changes

[devlead]

settings.UseLegacySyntax duplicated

[devlead]

Add ArgumentNullException.ThrowIfNull(context); ArgumentNullException.ThrowIfNull(settings);

[devlead]

Type should be DotCoverSettings