From 8d7f03dac8739afed890af0c0921965786c5e83c Mon Sep 17 00:00:00 2001
From: David Lord <davidism@gmail.com>
Date: Mon, 28 Mar 2022 10:20:42 -0700
Subject: treat empty auto_envvar as None

---
 src/click/core.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

(limited to 'src')

diff --git a/src/click/core.py b/src/click/core.py
index 939ad81..18431cd 100644
--- a/src/click/core.py
+++ b/src/click/core.py
@@ -2834,7 +2834,10 @@ class Option(Parameter):
             envvar = f"{ctx.auto_envvar_prefix}_{self.name.upper()}"
             rv = os.environ.get(envvar)
 
-        return rv
+            if rv:
+                return rv
+
+        return None
 
     def value_from_envvar(self, ctx: Context) -> t.Optional[t.Any]:
         rv: t.Optional[t.Any] = self.resolve_envvar_value(ctx)
-- 
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