From 06faa0bfdaa2a24e52b28efa4ce62eb2ae8b8d17 Mon Sep 17 00:00:00 2001
From: Thomas Kluyver <thomas@kluyver.me.uk>
Date: Mon, 20 Jan 2025 22:22:38 +0000
Subject: [PATCH] Allow unrecognised license IDs with FLIT_ALLOW_INVALID

---
 flit_core/flit_core/config.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/flit_core/flit_core/config.py b/flit_core/flit_core/config.py
index ed62ded4..c76a189e 100644
--- a/flit_core/flit_core/config.py
+++ b/flit_core/flit_core/config.py
@@ -765,6 +765,10 @@ def normalize_license_expr(s: str):
     try:
         info = licenses[ls]
     except KeyError:
+        if os.environ.get('FLIT_ALLOW_INVALID'):
+            log.warning("Invalid license ID {!r} allowed by FLIT_ALLOW_INVALID"
+                        .format(s))
+            return s
         raise ConfigError(f"{s!r} is not a recognised SPDX license ID")
 
     return info['id'] + ('+' if or_later else '')