Restore error summary

[aelij]

NuGet Product(s) Involved

MSBuild.exe, dotnet.exe

The Elevator Pitch

When updating a very large legacy monorepo to SDK-style projects, NuGet restore spewed out thousands of errors. It was difficult to browse through all the text and identify the root causes. I created a small summary tool using the binlog parser and regex error message grouping (which removed project-specific text), and it proved most helpful:

#r "nuget: MSBuild.StructuredLogger, 2.1.790"
using Microsoft.Build.Logging.StructuredLogger;

var log = BinaryLog.ReadBuild(@"msbuild.binlog");
var errors = log.FindChildrenRecursive<Error>().DumpAs(t => t.Count);
errors.GroupBy(c => c.Code).Select(c => (code: c.Key, messages: c.GroupBy(m => ResolveText(c.Key, m.Text), m => m.File))).Dump();

static string ResolveText(string code, string text) => code switch
	{
		"NU1602" => Regex.Match(text, @"for dependency ([-\w\.]+)\.").Value,
		"NU1605" or "NU1109" => Regex.Match(text, @"Detected package downgrade: ([-\w\.]+) from ([-\w\.]+) to (centrally defined)? ([-\w\.]+)").Value,
		"NU1603" => Regex.Match(text, @"([-\w\.]+) ([-\w\.]+) depends on ([-\w\.]+) \(>= ([-\w\.]+)\)").Value,
		_ => text
	};

The output looks something like this:

- NU1202
  - Package x.y 1.2.3 is not compatible with ...
    - path/to/p1.csproj
    - path/to/p2.csproj
  - Package a.b 3.4.5 is not compatible with ...
    - path/to/p3.csproj
- NU1605
  - Detected package downgrade: x.y ...
    - path/to/p4.csproj

I propose that the restore target of a root traversal project optionally emit such a text summary at the end. For error grouping, perhaps use the ShortenedText property and remove project-specific data from it.

Additional Context and Details

No response