diff --git a/flake.nix b/flake.nix
index e7b0422e..d3fca85c 100644
--- a/flake.nix
+++ b/flake.nix
@@ -50,6 +50,9 @@
             "-static-libstdc++"
           ]);
 
+          GIT_REVISION = if self ? rev then self.rev else "dirty";
+          GIT_REVISION_DATE = (builtins.concatStringsSep "-" (builtins.match "(.{4})(.{2})(.{2}).*" self.lastModifiedDate)) + " " + (builtins.concatStringsSep ":" (builtins.match "^........(.{2})(.{2})(.{2}).*" self.lastModifiedDate));
+
           postInstall = ''
             moveToOutput bin "$bin"
           '';
diff --git a/git_watcher.cmake b/git_watcher.cmake
index ab135e80..78e57ba1 100644
--- a/git_watcher.cmake
+++ b/git_watcher.cmake
@@ -139,6 +139,8 @@ function(GetGitState _working_dir)
     RunGitCommand(show -s "--format=%H" ${object})
     if(exit_code EQUAL 0)
         set(ENV{GIT_HEAD_SHA1} ${output})
+    else()
+        set(ENV{GIT_HEAD_SHA1} "$ENV{GIT_REVISION}")
     endif()
 
     RunGitCommand(show -s "--format=%an" ${object})
@@ -154,6 +156,8 @@ function(GetGitState _working_dir)
     RunGitCommand(show -s "--format=%ci" ${object})
     if(exit_code EQUAL 0)
         set(ENV{GIT_COMMIT_DATE_ISO8601} "${output}")
+    else()
+        set(ENV{GIT_COMMIT_DATE_ISO8601} "$ENV{GIT_REVISION_DATE}")
     endif()
 
     RunGitCommand(show -s "--format=%s" ${object})