Compare prerelease versions correctly for updates

install.ps1

@@ -100,8 +100,43 @@ function Release-LatestTagDownloadUrl {
     return $null
 }
 
+function Version-Core($Value) {
+    $base = $Value.TrimStart("v").Split("+")[0]
+    $base.Split("-")[0]
+}
+
+function Version-Prerelease($Value) {
+    $base = $Value.TrimStart("v").Split("+")[0]
+    $dash = $base.IndexOf("-")
+    if ($dash -lt 0) {
+        return ""
+    }
+    $base.Substring($dash + 1).ToLowerInvariant()
+}
+
 function Version-Parts($Value) {
-    [regex]::Matches($Value, "\d+") | ForEach-Object { [int64]$_.Value }
+    [regex]::Matches((Version-Core $Value), "\d+") | ForEach-Object { [int64]$_.Value }
+}
+
+function Compare-Prerelease($Left, $Right) {
+    if (-not $Left -and -not $Right) {
+        return 0
+    }
+    if (-not $Left) {
+        return 1
+    }
+    if (-not $Right) {
+        return -1
+    }
+    if ($Left -eq $Right) {
+        return 0
+    }
+    if ($Left -match "(?i)^rc(\d+)$" -and $Right -match "(?i)^rc(\d+)$") {
+        $leftRc = [int64]([regex]::Match($Left, "(?i)^rc(\d+)$").Groups[1].Value)
+        $rightRc = [int64]([regex]::Match($Right, "(?i)^rc(\d+)$").Groups[1].Value)
+        return $leftRc.CompareTo($rightRc)
+    }
+    return [string]::CompareOrdinal($Left, $Right)
 }
 
 function Compare-DoshVersion($Left, $Right) {
@@ -114,7 +149,7 @@ function Compare-DoshVersion($Left, $Right) {
         if ($l -lt $r) { return -1 }
         if ($l -gt $r) { return 1 }
     }
-    return 0
+    return Compare-Prerelease (Version-Prerelease $Left) (Version-Prerelease $Right)
 }
 
 function Current-SourceVersion {