Excluding projects

There are two exclusion options, and they differ in kind rather than degree.

Option	The project is…	Its dependents…
--exclude-output	discovered and evaluated, but left out of the results	are still found through it
--exclude-discovery	dropped before the graph is built, so it is not a starting point	are unaffected — unless they reference it

Both take a .NET regular expression matched against each project’s full path.

--exclude-output

Use this to keep something out of the build set while leaving the analysis intact: benchmarks, samples, a project your pipeline handles separately.

dotnet affected --dry-run --verbose --exclude-output '\.Benchmarks\.csproj$'

1 files have changed referenced by 1 projects
0 NuGet Packages have changed
7 projects are affected by these changes
1 projects were excluded
Changed Projects
Name                         Path
DotnetAffected.Abstractions  /repo/src/DotnetAffected.Abstractions/DotnetAffected.Abstractions.csproj

Affected Projects
Name                       Path
dotnet-affected            /repo/src/dotnet-affected/dotnet-affected.csproj
dotnet-affected.Tests      /repo/test/dotnet-affected.Tests/dotnet-affected.Tests.csproj
...

Excluded Projects
Name                        Path
dotnet-affected.Benchmarks  /repo/benchmarks/dotnet-affected.Benchmarks/dotnet-affected.Benchmarks.csproj

Because the project is still evaluated, changes flow through it: excluding a mid-chain library keeps everything depending on that library in the results.

Caution

One edge case does not follow that rule. Exclusion is applied to the changed projects before the graph is walked, so when the pattern matches a project that itself changed, its dependents are never discovered. Excluding a changed library in a repository where nothing else changed reports No affected projects where found for the current changes.

--exclude-discovery

Use this when a project cannot be loaded at all — a project MSBuild fails to evaluate would otherwise take the whole run down while the graph is being built.

dotnet affected --verbose --exclude-discovery '/legacy/'

1 files have changed referenced by 1 projects
0 NuGet Packages have changed
7 projects are affected by these changes
0 projects were excluded
1 projects were excluded from discovery
...

Projects Excluded from Discovery
Path
/repo/benchmarks/dotnet-affected.Benchmarks/dotnet-affected.Benchmarks.csproj

The two lists are reported separately, and the discovery line only appears when something was actually excluded that way. Excluded-from-discovery projects are listed by path alone: nothing evaluated them at discovery time, so there is no project name to show.

It removes starting points, not projects

Exclusion happens to the discovered set — the projects the graph is built from. MSBuild then follows ProjectReference items from those entry points, so a project excluded from discovery that another discovered project references is pulled back into the graph, and can still show up as affected.

It reliably keeps out projects nothing references — the usual case for a broken or legacy project sitting on its own. To keep a referenced project out of the results, use --exclude-output as well.

Writing the pattern

• The pattern is matched with Regex.IsMatch against the project’s absolute path, so it matches anywhere in the path — it is not anchored, and it is not a glob.
• . is a regex wildcard. .Tests. matches any path containing Tests with any character on either side; to match a literal dot, escape it: '\.Tests\.'.
• Matching is case-sensitive unless you say otherwise: '(?i)tests'.

# Everything under a directory
dotnet affected --exclude-output '/samples/'

# Test projects by file name
dotnet affected --exclude-output '\.Tests\.csproj$'

# Two things at once
dotnet affected --exclude-output '(/samples/|\.Benchmarks\.csproj$)'

--exclude is obsolete

-e/--exclude still works and behaves exactly like --exclude-output, which it is now an alias for. When both are given, --exclude-output wins.

Exclusion and the “nothing changed” exit code

Exclusion happens before the result is judged empty, so excluding everything that changed produces exit code 166 — the same as if nothing had changed at all. See Exit codes.