1 files changed, 55 insertions, 0 deletions
diff --git a/scripts/update_version_stamp.lua b/scripts/update_version_stamp.lua
new file mode 100755
index 0000000000..11b521fab6
--- /dev/null
+++ b/scripts/update_version_stamp.lua
@@ -0,0 +1,55 @@
+#!/usr/bin/env lua
+--
+-- Script to update the Git version stamp during build.
+-- This is called via the custom update_version_stamp target in
+-- src/nvim/CMakeLists.txt.
+--
+-- arg[1]: file in which to update the version string
+-- arg[2]: prefix to use always ("vX.Y.Z")
+
+local function die(msg)
+  io.stderr:write(string.format('%s: %s\n', arg[0], msg))
+  -- No error, fall back to using generated "-dev" version.
+  os.exit(0)
+end
+
+local function iswin()
+  return package.config:sub(1,1) == '\\'
+end
+
+if #arg ~= 2 then
+  die(string.format("Expected two args, got %d", #arg))
+end
+
+local versiondeffile = arg[1]
+local prefix = arg[2]
+
+local dev_null = iswin() and 'NUL' or '/dev/null'
+local described = io.popen('git describe --first-parent --dirty 2>'..dev_null):read('*l')
+if not described then
+  described = io.popen('git describe --first-parent --tags --always --dirty'):read('*l')
+end
+if not described then
+  io.open(versiondeffile, 'w'):write('\n')
+  die('git-describe failed, using empty include file.')
+end
+
+-- `git describe` annotates the most recent tagged release; for pre-release
+-- builds we must replace that with the unreleased version.
+local with_prefix = described:gsub("^v%d+%.%d+%.%d+", prefix)
+if described == with_prefix then
+  -- Prepend the prefix always, e.g. with "nightly-12208-g4041b62b9".
+  with_prefix = prefix .. "-" .. described
+end
+
+-- Read existing include file.
+local current = io.open(versiondeffile, 'r')
+if current then
+  current = current:read('*l')
+end
+
+-- Write new include file, if different.
+local new = '#define NVIM_VERSION_MEDIUM "'..with_prefix..'"'
+if current ~= new then
+  io.open(versiondeffile, 'w'):write(new .. '\n')
+end