From 419a9d4a38cdb63c049780c19c5c492c37fc154e Mon Sep 17 00:00:00 2001
From: Rainer Sigwald <raines@microsoft.com>
Date: Wed, 18 Apr 2018 11:44:26 -0500
Subject: [PATCH] Report better version for VS preview consoles

For prereleases, the Visual Studio command prompt sets the environment
variable `VSCMD_VER` to a value like `15.7.0-pre.3.0`, which is not
parseable by System.Version.

This could be handled by using a version parser that can handle this
SemVer 2 version as well as Windows 4-part versions, but that would be
another dependency, so I just special-cased the problematic dash.
---
 .../Discovery/Providers/DevConsoleInstanceProvider.cs | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/OmniSharp.Host/MSBuild/Discovery/Providers/DevConsoleInstanceProvider.cs b/src/OmniSharp.Host/MSBuild/Discovery/Providers/DevConsoleInstanceProvider.cs
index a8c4398787..9e5d218e1f 100644
--- a/src/OmniSharp.Host/MSBuild/Discovery/Providers/DevConsoleInstanceProvider.cs
+++ b/src/OmniSharp.Host/MSBuild/Discovery/Providers/DevConsoleInstanceProvider.cs
@@ -36,6 +36,17 @@ public override ImmutableArray<MSBuildInstance> GetInstances()
             var versionString = Environment.GetEnvironmentVariable("VSCMD_VER");
             Version.TryParse(versionString, out var version);
 
+            if (version == null)
+            {
+                var dashIndex = versionString.IndexOf('-');
+
+                if (dashIndex > 0)
+                {
+                    versionString = versionString.Substring(0, dashIndex);
+                    Version.TryParse(versionString, out version);
+                }
+            }
+
             if (version == null)
             {
                 versionString = Environment.GetEnvironmentVariable("VisualStudioVersion");