From fe2c558ba66dd6a12cf9289adf692c9a76c71ef4 Mon Sep 17 00:00:00 2001
From: Brad King <brad.king@kitware.com>
Date: Thu, 25 Jul 2019 09:17:53 -0400
Subject: CMakeVersion: Preserve Git information during 'git archive'

Use `export-subst` to get information about the Git commit used to
produce an archive.
---
 Source/.gitattributes     | 2 ++
 Source/CMakeVersion.cmake | 3 +++
 2 files changed, 5 insertions(+)

diff --git a/Source/.gitattributes b/Source/.gitattributes
index 7c160cc..d0aedc2 100644
--- a/Source/.gitattributes
+++ b/Source/.gitattributes
@@ -1,2 +1,4 @@
+CMakeVersion.cmake    export-subst
+
 # Do not format third-party sources.
 /kwsys/**                                  -format.clang-format-6.0
diff --git a/Source/CMakeVersion.cmake b/Source/CMakeVersion.cmake
index 32a40f9..193c14f 100644
--- a/Source/CMakeVersion.cmake
+++ b/Source/CMakeVersion.cmake
@@ -39,6 +39,9 @@ if(COMMAND _git)
   # Get the commit checked out in this work tree.
   _git(log -n 1 HEAD "--pretty=format:%h %s" --)
   set(git_info "${_git_out}")
+else()
+  # Get the commit exported by 'git archive'.
+  set(git_info [==[$Format:%h %s$]==])
 endif()
 
 # Extract commit information if available.
-- 
cgit v0.12