dotnet restore will treat all sources as local if the first source is local

[smaglio81]

NuGet Product Used

dotnet.exe

Product Version

9.0.306

Worked before?

No response

Impact

It's more difficult to complete my work

Repro Steps & Context

Describe the bug

dotnet restore will treat all sources passed in using the -s parameter as local if the first source is local.

dotnet restore dotnetrestoretest.csproj -s "C:\Program Files (x86)\Microsoft SDKs\NuGetPackages" -s https://api.nuget.org/v3/index.json

To Reproduce

There is a repository which can reproduce the error.

• https://github.com/smaglio81/dotnetrestorelocal

The project intentionally references a non-existant nuget package version (Microsoft.Extensions.DependencyInjection 8.2.00001), because that forces dotnet to search the sources for the package.

This is what the issue looks like

Exceptions (if any)

error NU1301: The local source 'D:\workspace\dotnetrestorelocal\dotnetrestoretest\https:\api.nuget.org\v3\index.json' doesn't exist.

Further technical details

details of dotnet --info

.NET SDK: Version: 9.0.306 Commit: cc9947ca66 Workload version: 9.0.300-manifests.abe91478 MSBuild version: 17.14.28+09c1be848

Runtime Environment:
OS Name: Windows
OS Version: 10.0.22631
OS Platform: Windows
RID: win-x64
Base Path: C:\Program Files\dotnet\sdk\9.0.306\

.NET workloads installed:
There are no installed workloads to display.
Configured to use loose manifests when installing new manifests.

Host:
Version: 9.0.10
Architecture: x64
Commit: e1f19886fe

.NET SDKs installed:
9.0.306 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.App 8.0.21 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 9.0.10 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 8.0.14 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 8.0.21 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 9.0.10 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 8.0.14 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 8.0.21 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 9.0.10 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
x86 [C:\Program Files (x86)\dotnet]
registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
Not set

global.json file:
Not found

Learn more:
https://aka.ms/dotnet/info

Download .NET:
https://aka.ms/dotnet/download

VS Code details

Version: 1.102.0 (user setup) Commit: cb0c47c0cfaad0757385834bd89d410c78a856c0 Date: 2025-07-09T22:10:34.600Z Electron: 35.6.0 ElectronBuildId: 11847422 Chromium: 134.0.6998.205 Node.js: 22.15.1 V8: 13.4.114.21-electron.0 OS: Windows_NT x64 10.0.22631

Previously submitted as dotnet/sdk#51514

Verbose Logs

PS D:\workspace\dotnetrestorelocal\dotnetrestoretest> dotnet restore dotnetrestoretest.csproj -s "C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\\" -s https://api.nuget.org/v3/index.json --verbosity diag
C:\Program Files\dotnet\sdk\9.0.306\MSBuild.dll -nologo -distributedlogger:Microsoft.DotNet.Tools.MSBuild.MSBuildLogger,C:\Program Files\dotnet\sdk\9.0.306\dotnet.dll*Microsoft.DotNet.Tools.MSBuild.MSBuildForwardingLogger,C:\Program Files\dotnet\sdk\9.0.306\dotnet.dll -maxcpucount -property:RestoreSources=C:\Program Files (x86)\Microsoft SDKs\NuGetPackages\%3Bhttps:%2F%2Fapi.nuget.org/v3/index.json -target:Restore -tlp:default=auto -verbosity:m -verbosity:diag dotnetrestoretest.csproj
    Determining projects to restore...
    D:\workspace\dotnetrestorelocal\dotnetrestoretest\dotnetrestoretest.csproj : error NU1301: The local source 'D:\workspace\dotnetrestorelocal\dotnetrestoretest\https:\api.nuget.org\v3\index.json' doesn't exist.
    Failed to restore D:\workspace\dotnetrestorelocal\dotnetrestoretest\dotnetrestoretest.csproj (in 69 ms).
                                                                                                                                                                                         
Restore failed with 1 error(s) in 0.3s

[johnbrimley]

I took a look at this and was able to identify the issue.

In the SDK parameters like RuntimeIdentifiers and RestoreSources are concatenated together using "%3B" (semi-colon). In the GetRestoreSettingsTask the expectation is that RestoreSources and RestoreSourcesOverride will be string arrays.

The targets file passes them a PropertyGroup instead of ItemGroup so we end up with a single string in the array like...

"C:\Program Files (x86)\Microsoft SDKs\NuGetPackages;https://api.nuget.org/v3/index.json".

This is then mangled into...

"C:\Program Files (x86)\Microsoft SDKs\NuGetPackages;https:\api.nuget.org\v3\index.json"

And sent out in the OutputSources array.

From my perspective there are a couple options.

1. Change the task so that RestoreSources and RestoreSourcesOverride are strings and then explicitly split them with something like MSBuildStringUtility.Split.

2. Leave the properties as they are and update the targets file to split them before they are sent.

Option 1 presents more testability, but if the GetRestoreSettingsTask is considered part of the public API then changing its signature might break other workflows.

[jebriede]

Thanks for reporting the issue! I was able to repro the issue as specified.