Add GIT_VERSION magic constant

sds · sds · commit 40384fce79bb · 2015-04-10T05:11:23.000Z
Add a constant which makes it convenient to execute code based on the
version of git we're running. Returning the `Overcommit::Utils::Version`
class, doing a comparison is now as simple as writing:

    if GIT_VERSION &lt; '1.8.5'
      ...
    end
diff --git a/lib/overcommit.rb b/lib/overcommit.rb
@@ -1,5 +1,7 @@
 require 'overcommit/constants'
 require 'overcommit/exceptions'
+require 'overcommit/utils'
+require 'overcommit/git_version'
 require 'overcommit/configuration_validator'
 require 'overcommit/configuration'
 require 'overcommit/configuration_loader'
@@ -16,5 +18,4 @@
 require 'overcommit/hook_runner'
 require 'overcommit/installer'
 require 'overcommit/logger'
-require 'overcommit/utils'
 require 'overcommit/version'
diff --git a/lib/overcommit/git_version.rb b/lib/overcommit/git_version.rb
@@ -0,0 +1,15 @@
+# Returns the version of the available git binary.
+#
+# This is intended to be used to conveniently execute code based on a specific
+# git version. Simply compare to a version string:
+#
+# @example
+#   if GIT_VERSION <= '1.8.5'
+#     ...
+#   end
+module Overcommit
+  GIT_VERSION = begin
+    version = `git --version`.chomp[/[\d\.]+/, 0]
+    Overcommit::Utils::Version.new(version)
+  end
+end
