Action reference

Inputs

Every input is optional.

Input	Sends	Description
toolVersion	dotnet tool install --version	Version of dotnet-affected to install. Defaults to 7.*, the major @v7 targets. Takes NuGet range syntax
repository-path	--repository-path	The checkout to analyse. Defaults to the workspace. Output files are written here
from	--from	The baseline to compare the working tree against. Defaults to the checked-out commit
uncommitted	--uncommitted	all, staged or none — see the default
filter-file-path	--filter-file-path	Filter file used to discover projects: .sln, .slnx or .slnf
exclude-output	--exclude-output	.NET regex; matching projects are evaluated and still affect their dependents, but stay out of the output
exclude-discovery	--exclude-discovery	.NET regex; matching projects are never loaded
no-gitignore	--no-gitignore	Discover projects inside paths git ignores. Defaults to false
output-format	--format	Space-separated: text, traversal, json, slnf. Defaults to text traversal

Deprecated inputs

Kept so no workflow breaks on the upgrade. Each one logs a warning, and each loses to its replacement when both are set.

Input	Sends	Behaviour
to	nothing	Warns and is ignored — see below
solution-path	--filter-file-path	Warns; filter-file-path wins if both are set
exclude	--exclude-output	Warns; exclude-output wins if both are set

The uncommitted default

The tool defaults to all, which suits a developer running it on a checkout they are editing. A CI job is not that: restore, code generation and version stamping all run before this step, and every one of those writes would otherwise count as a change. So the action picks:

from	Default	Why
set	none	Compare the commits alone, so earlier steps cannot change which projects are reported
unset	all	--from then defaults to the checked-out commit; ignoring the working tree too would compare that commit with itself and report nothing on every run

Set the input explicitly to override either.

The to input

Deprecated, warns, and is not passed to the tool at all. dotnet-affected 7 ends every comparison at the working tree, which Actions has already checked out at the commit being built, so the input has nothing left to name.

It is accepted rather than removed so that a workflow which has not migrated yet gets one clear message instead of a parse error. Drop it and use uncommitted — see Choosing what to compare.

output-format and the affected output

The affected output is read from affected.txt, so it is only set when the format list contains text. The default (text traversal) covers both: a file list for the output, and affected.proj for dotnet build.

Asking for traversal alone leaves affected empty on every run, which reads exactly like “nothing was affected” — and step conditions built on it silently skip everything.

slnf needs a solution to reference, so pair it with filter-file-path. The tool refuses the combination otherwise, while parsing arguments.

Outputs

Output	Description
affected	Contents of affected.txt: one project path per line. Empty when nothing changed

Files written

Into repository-path, which defaults to the workspace:

File	When
affected.proj	traversal is in the format list
affected.txt	text is in the format list
affected.json	json is in the format list
affected.slnf	slnf is in the format list

Nothing is written when nothing changed — the run exits 166 first.

Version guard

After installing, the action reads back dotnet affected --version and stops if the major is newer than the one it targets, naming the action version to move to. A version it cannot parse is let through: this check must never be what breaks a run that would otherwise have worked.

Older majors are allowed, so pinning toolVersion to an earlier release still works.

Exit-code handling

Tool exit	Action behaviour
0	Sets affected from affected.txt
166	Succeeds with an empty affected output — nothing changed
anything else	Logs the tool’s stderr and fails the step

Requirements

• fetch-depth: 0 on actions/checkout. A shallow clone lacks the baseline and any merge base.
• A .NET SDK on the runner. GitHub’s hosted images ship one; with actions/setup-dotnet, run it before this action so dotnet tool install has something to install into.
• $GITHUB_WORKSPACE — the action fails without it, which in practice means it only runs inside Actions.