Merge pull request #4452 from fsprojects/repo-assist/fix-issue-4443-slnx-restore-ee71a070001dd7c1

[repo-assist] Support .slnx solutions in paket restore (#4443)

Author: fpellet

RELEASE_NOTES.md

@@ -1,5 +1,6 @@
 #### Unreleased
 
+* Add support for `.slnx` solution files - https://github.com/fsprojects/Paket/issues/4443
 * Do not warn about missing "redirects: force" for FSharp.Core in projects targeting net5.0 and later - https://github.com/fsprojects/Paket/issues/4455
 
 #### 12.0.0-alpha001 - 2026-10-11

src/Paket.Core/Common/Utils.fs

@@ -501,7 +501,10 @@ let RunInLockedAccessMode(lockedFolder,lockedAction: unit -> bool) =
 
         releaseLock 5
         if runDotNetRestore then
-            let slnFiles = rootFolder.GetFiles("*.sln", SearchOption.TopDirectoryOnly)
+            let slnFiles =
+                [| yield! rootFolder.GetFiles("*.sln", SearchOption.TopDirectoryOnly)
+                   yield! rootFolder.GetFiles("*.slnx", SearchOption.TopDirectoryOnly) |]
+                |> Array.distinctBy (fun f -> f.FullName)
             if Array.isEmpty slnFiles then
                 let projFiles = rootFolder.GetFiles("*.*proj", SearchOption.TopDirectoryOnly)