Fixes #576 - fails to load with older versions of git

Author: eamodio

CHANGELOG.md

@@ -8,6 +8,7 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/) and this p
 
 ### Fixed
 
+- Fixes [#576](https://github.com/eamodio/vscode-gitlens/issues/576) — Fails to load with older versions of git
 - Fixes an issue where the _Copy Commit Message to Clipboard_ command fails (and probably others too) — a regression caused by the attempted fix for [#568](https://github.com/eamodio/vscode-gitlens/issues/565)
 
 ## [9.0.2] - 2018-12-05

src/git/git.ts

@@ -69,7 +69,8 @@ const GitWarnings = {
     mustRunInWorkTree: /this operation must be run in a work tree/i,
     patchWithConflicts: /Applied patch to \'.*?\' with conflicts/i,
     noRemoteRepositorySpecified: /No remote repository specified\./i,
-    remoteConnectionError: /Could not read from remote repository/i
+    remoteConnectionError: /Could not read from remote repository/i,
+    notAGitCommand: /\'.+\' is not a git command/i
 };
 
 export enum GitErrorHandling {

src/git/gitService.ts

@@ -1132,7 +1132,7 @@ export class GitService implements Disposable {
         const author = `${user.name} <${user.email}>`;
         // Check if there is a mailmap for the current user
         const mappedAuthor = await Git.check_mailmap(repoPath, author);
-        if (author !== mappedAuthor) {
+        if (mappedAuthor != null && mappedAuthor.length !== 0 && author !== mappedAuthor) {
             match = mappedAuthorRegex.exec(mappedAuthor);
             if (match != null) {
                 [, user.name, user.email] = match;