From 86e476c8d1f6776bf330059efe7cf46ce279592b Mon Sep 17 00:00:00 2001
From: Andrew Lytvynov <awly@tailscale.com>
Date: Wed, 10 Jan 2024 09:03:11 -0800
Subject: [PATCH] version/mkversion: allow version override with
 $TS_VERSION_OVERRIDE (#10799)

This is useful to build local binaries with custom versions to test
version-specific logic (like updates).

Updates https://github.com/tailscale/corp/issues/16703

Signed-off-by: Andrew Lytvynov <awly@tailscale.com>
---
 version/mkversion/mkversion.go | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/version/mkversion/mkversion.go b/version/mkversion/mkversion.go
index a7d60f528..c09473256 100644
--- a/version/mkversion/mkversion.go
+++ b/version/mkversion/mkversion.go
@@ -199,6 +199,13 @@ func tailscaleModuleRef(modBs []byte) (string, error) {
 }
 
 func mkOutput(v verInfo) (VersionInfo, error) {
+	if override := os.Getenv("TS_VERSION_OVERRIDE"); override != "" {
+		var err error
+		v.major, v.minor, v.patch, err = parseVersion(override)
+		if err != nil {
+			return VersionInfo{}, fmt.Errorf("failed to parse TS_VERSION_OVERRIDE: %w", err)
+		}
+	}
 	var changeSuffix string
 	if v.minor%2 == 1 {
 		// Odd minor numbers are unstable builds.