From 69e3a256e8be1bc6586db6a47eb4fa3dc7c21cff Mon Sep 17 00:00:00 2001
From: Rafael Vuijk <r.vuijk@sownet.nl>
Date: Sun, 9 Aug 2026 11:22:26 +0000
Subject: [PATCH] Pin the language version instead of building on preview

`preview` tracks whatever the installed SDK considers unreleased, so the
semantics of the code compiled here could change between SDK patch releases
with no signal in the repository. For a library that ships strong-named
binaries that is a dependency on a moving target rather than a feature.

C# projects pin to 14.0, which supplies everything preview did that this
repository uses, including extension members. F# does not accept a numeric
LangVersion of 14.0 -- FSC rejects it with FS0246 -- so the property is now
scoped by project extension and the F# wrappers take `latest`, the stable
equivalent of what they had.

The two analyzer projects still fail to build on Linux for an unrelated
reason (NETSDK1060 out of a backslash-separated ProjectReference); that is
unchanged by this commit and was verified against master.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
---
 Sources/AngouriMath/AngouriMath.csproj    |  2 +-
 Sources/Directory.Build.props             | 11 +++++++++--
 Sources/Samples/Samples/Playground.csproj |  2 +-
 3 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/Sources/AngouriMath/AngouriMath.csproj b/Sources/AngouriMath/AngouriMath.csproj
index ca37596de..c851c7e03 100644
--- a/Sources/AngouriMath/AngouriMath.csproj
+++ b/Sources/AngouriMath/AngouriMath.csproj
@@ -9,7 +9,7 @@
   
   <PropertyGroup>
     <OutputType>Library</OutputType>
-    <LangVersion>preview</LangVersion>
+    <LangVersion>14.0</LangVersion>
     <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
     <PackageTags>$(PackageTags), csharp</PackageTags>
     <Description>Enables to work with formulas built in the code or from a string. Computing, derivating, latex rendering, compilation, solving equations and systems of equations analytycally, simplification, and much more. Read more on https://am.angouri.org.</Description>
diff --git a/Sources/Directory.Build.props b/Sources/Directory.Build.props
index 481c603c1..9bc2f78b9 100644
--- a/Sources/Directory.Build.props
+++ b/Sources/Directory.Build.props
@@ -1,7 +1,14 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project>
   <PropertyGroup>
-    <LangVersion>preview</LangVersion>
     <Nullable>enable</Nullable>
   </PropertyGroup>
-</Project>
\ No newline at end of file
+
+  <PropertyGroup Condition="'$(MSBuildProjectExtension)' == '.csproj'">
+    <LangVersion>14.0</LangVersion>
+  </PropertyGroup>
+
+  <PropertyGroup Condition="'$(MSBuildProjectExtension)' == '.fsproj'">
+    <LangVersion>latest</LangVersion>
+  </PropertyGroup>
+</Project>
diff --git a/Sources/Samples/Samples/Playground.csproj b/Sources/Samples/Samples/Playground.csproj
index 5394f4baa..efec86aef 100644
--- a/Sources/Samples/Samples/Playground.csproj
+++ b/Sources/Samples/Samples/Playground.csproj
@@ -3,7 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net10.0</TargetFramework>
-    <LangVersion>preview</LangVersion>
+    <LangVersion>14.0</LangVersion>
     <Nullable>enable</Nullable>
   </PropertyGroup>