Allow Version class to deal with HEAD as a version hash

mminns · mminns · commit 3874ddaed4b3 · 2017-05-18T19:51:20.000+01:00
The Version code expects a commit Hash to be used to specifiy the version of code in use in the library. However this can also be HEAD. If it is HEAD the current code will crash as it tries to extract 7 characters out of 4.
diff --git a/LibGit2Sharp/Version.cs b/LibGit2Sharp/Version.cs
@@ -69,7 +69,8 @@ private string RetrieveAbbrevShaFrom(string name)
         {
             string sha = ReadContentFromResource(assembly, name) ?? "unknown";
 
-            return sha.Substring(0, 7);
+            var index = sha.Length > 7 ? 7 : sha.Length;
+            return sha.Substring(0, index);
         }
 
         /// <summary>
diff --git a/LibGit2Sharp/libgit2sharp_hash.txt b/LibGit2Sharp/libgit2sharp_hash.txt
@@ -1 +1 @@
-unknown
+HEAD

Original file line number	Diff line number	Diff line change
`@@ -69,7 +69,8 @@ private string RetrieveAbbrevShaFrom(string name)`
`69`	`69`	`{`
`70`	`70`	`string sha = ReadContentFromResource(assembly, name) ?? "unknown";`
`71`	`71`
`72`		`- return sha.Substring(0, 7);`
	`72`	`+ var index = sha.Length > 7 ? 7 : sha.Length;`
	`73`	`+ return sha.Substring(0, index);`
`73`	`74`	`}`
`74`	`75`
`75`	`76`	`/// <summary>`