Use a common target framework from all of your projects

CHANGELOG.md

@@ -4,6 +4,8 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 ## [Unreleased]
+* Select common target framework when multiple projects are found
+  - By @AdeAttwood in https://github.com/razzmatazz/csharp-language-server/pull/253
 * Fix how completion item details are resolved
   - https://github.com/razzmatazz/csharp-language-server/pull/251
 * Apply simple heuristics to select a .sln/.slnx file when multiple are found.

src/CSharpLanguageServer/RoslynHelpers.fs

@@ -56,7 +56,7 @@
     override __.Visit(node) =
         if sym.Kind = SymbolKind.Method then
             if node :? MethodDeclarationSyntax then
                 let nodeMethodDecl = node :?> MethodDeclarationSyntax
 
                 if nodeMethodDecl.Identifier.ValueText = sym.Name then
                     let methodArityMatches =
@@ -428,7 +428,7 @@
     | Unknown
 
 
-let selectMostCapableCompatibleTfm (tfms: string seq) : string option =
+let selectLatestTfm (tfms: string seq) : string option =
     let parseTfm (tfm: string) : TfmCategory =
         let patterns = [
             @"^net(?<major>\d)(?<minor>\d)?(?<build>\d)?$", NetFramework
@@ -466,8 +466,8 @@
     |> Seq.tryHead
 
 
-let applyWorkspaceTargetFrameworkProp (logger: ILog) (projs: string seq) props =
-    let tfms = new List<string>()
+let loadProjectTfms (logger: ILog) (projs: string seq) : Map<string, list<string>> =
+    let mutable projectTfms = Map.empty
 
     for projectFilename in projs do
         let projectCollection = new Microsoft.Build.Evaluation.ProjectCollection();
@@ -478,51 +478,51 @@
 
             let noneIfEmpty s =
                 s |> Option.ofObj
-                    |> Option.bind (fun s -> if String.IsNullOrEmpty(s) then None else Some s)
+                  |> Option.bind (fun s -> if String.IsNullOrEmpty(s) then None else Some s)
 
-            let targetFramework = buildProject.GetPropertyValue("TargetFramework") |> noneIfEmpty
+            let targetFramework =
+                match buildProject.GetPropertyValue("TargetFramework") |> noneIfEmpty with
+                | Some tfm -> [tfm.Trim()]
+                | None -> []
 
-            match targetFramework with
-            | Some tfm ->
-                tfms.Add(tfm.Trim())
-            | _ -> ()
+            let targetFrameworks =
+                match buildProject.GetPropertyValue("TargetFrameworks") |> noneIfEmpty with
+                | Some tfms -> tfms.Split(";") |> Array.map (fun s -> s.Trim()) |> List.ofArray
+                | None -> []
 
-            let targetFrameworks = buildProject.GetPropertyValue("TargetFrameworks") |> noneIfEmpty
-
-            match targetFrameworks with
-            | Some semicolonSeparatedTfms ->
-                for tfm in semicolonSeparatedTfms.Split(";") do
-                    tfms.Add(tfm.Trim())
-            | _ -> ()
+            projectTfms <- projectTfms |> Map.add projectFilename (targetFramework @ targetFrameworks)
 
             projectCollection.UnloadProject(buildProject)
         with
         | :? InvalidProjectFileException as ipfe ->
             logger.debug (
-                Log.setMessage "applyWorkspaceTargetFrameworkProp: failed to load {projectFilename}: {ex}"
+                Log.setMessage "loadProjectTfms: failed to load {projectFilename}: {ex}"
                 >> Log.addContext "projectFilename" projectFilename
                 >> Log.addContext "ex" (string (ipfe.GetType()))
             )
 
-    let distinctTfms = tfms |> Set.ofSeq
+    projectTfms
 
-    logger.debug (
-        Log.setMessage "applyWorkspaceTargetFrameworkProp: distinctTfms={distinctTfms}"
-        >> Log.addContext "distinctTfms" (String.Join(";", distinctTfms))
-    )
 
-    match distinctTfms.Count with
-    | 0 -> props
-    | 1 -> props
-    | _ ->
-        match selectMostCapableCompatibleTfm distinctTfms with
-        | Some tfm -> props |> Map.add "TargetFramework" tfm
-        | None -> props
+let applyWorkspaceTargetFrameworkProp (tfmsPerProject: Map<string, list<string>>) props : Map<string, string> =
+    let selectedTfm =
+        match tfmsPerProject.Count with
+        | 0 -> None
+        | _ ->
+            tfmsPerProject.Values
+            |> Seq.map Set.ofSeq
+            |> Set.intersectMany
+            |> selectLatestTfm
 
+    match selectedTfm with
+    | Some tfm -> props |> Map.add "TargetFramework" tfm
+    | None -> props
 
 let resolveDefaultWorkspaceProps (logger: ILog) projs : Map<string, string> =
+    let tfmsPerProject = loadProjectTfms logger projs
+
     Map.empty
-    |> applyWorkspaceTargetFrameworkProp logger projs
+    |> applyWorkspaceTargetFrameworkProp tfmsPerProject
 
 
 let tryLoadSolutionOnPath

tests/CSharpLanguageServer.Tests/InternalTests.fs

@@ -1,15 +1,42 @@
 module CSharpLanguageServer.Tests.InternalTests
 
+open System
 open NUnit.Framework
 
 open CSharpLanguageServer.RoslynHelpers
 
-[<TestCase("net8.0", "net8.0")>]
-[<TestCase("net8.0;net10.0", "net10.0")>]
-[<TestCase("net8.0;netstandard2.0", "net8.0")>]
-[<TestCase("netstandard1.0;netstandard2.0", "netstandard2.0")>]
-[<TestCase("net40;net462;net6.0;net8.0;netcoreapp3.1;netstandard2.0", "net8.0")>]
-[<TestCase("net40;net462", "net462")>]
-let testTheMostCapableTfmIsSelected(tfmList: string, expectedTfm: string) =
-    let selectedTfm = tfmList.Split(";") |> selectMostCapableCompatibleTfm
-    Assert.AreEqual(expectedTfm |> Option.ofObj, selectedTfm)
+[<TestCase("1.csproj:net8.0", "net8.0")>]
+[<TestCase("1.csproj:net8.0,net10.0", "net10.0")>]
+[<TestCase("1.csproj:net8.0,netstandard2.0", "net8.0")>]
+[<TestCase("1.csproj:netstandard1.0,netstandard2.0", "netstandard2.0")>]
+[<TestCase("1.csproj:net40,net462,net6.0,net8.0,netcoreapp3.1,netstandard2.0", "net8.0")>]
+[<TestCase("1.csproj:net40,net462", "net462")>]
+[<TestCase("1.csproj:net8.0 2.csproj:net8.0", "net8.0")>]
+[<TestCase("1.csproj:net8.0,net10.0 2.csproj:netstandard2.0,net462", null)>]
+[<TestCase("1.csproj:net8.0,net10.0 2.csproj:net8.0,net10.0", "net10.0")>]
+[<TestCase("1.csproj:net8.0 2.csproj:net8.0,net10.0", "net8.0")>]
+let testApplyWorkspaceTargetFrameworkProp(tfmList: string, expectedTfm: string | null) =
+
+    let parseTfmList (projectEntry: string) : string * list<string> =
+        let parts = projectEntry.Split(':')
+        if parts.Length <> 2 then
+            failwithf "Invalid project entry format: '%s'. Expected 'ProjectName:tfm1,tfm2,...'" projectEntry
+        let projectName = parts.[0]
+        let tfmStrings = parts.[1].Split(',') |> List.ofSeq
+        (projectName, tfmStrings)
+
+    let tfmsPerProject: Map<string, list<string>> =
+        tfmList
+        |> _.Split([|' '|], StringSplitOptions.RemoveEmptyEntries)
+        |> Array.map parseTfmList
+        |> Map.ofArray
+
+    let props = Map.empty |> applyWorkspaceTargetFrameworkProp tfmsPerProject
+
+    Assert.AreEqual(expectedTfm |> Option.ofObj, props |> Map.tryFind "TargetFramework")
+
+[<TestCase>]
+let testApplyWorkspaceTargetFrameworkPropWithEmptyMap() =
+    let props = Map.empty |> applyWorkspaceTargetFrameworkProp Map.empty
+
+    Assert.AreEqual(None, props |> Map.tryFind "TargetFramework")