From a1cd868c0224f16d921a25f04cbc39cb03a5471d Mon Sep 17 00:00:00 2001
From: Phil Booth <pmbooth@gmail.com>
Date: Wed, 26 Sep 2018 06:49:21 +0100
Subject: Treat empty environment variables as unset

---
 Cargo.toml   |  1 +
 src/env.rs   |  5 +++++
 tests/env.rs | 12 ++++++++++++
 3 files changed, 18 insertions(+)

diff --git a/Cargo.toml b/Cargo.toml
index 7b783d6..cdca1dd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -19,6 +19,7 @@ json = ["serde_json"]
 yaml = ["yaml-rust"]
 hjson = ["serde-hjson"]
 ini = ["rust-ini"]
+ignore-empty-env-vars = []
 
 [dependencies]
 lazy_static = "1.0"
diff --git a/src/env.rs b/src/env.rs
index 51e91a9..d570932 100644
--- a/src/env.rs
+++ b/src/env.rs
@@ -74,6 +74,11 @@ impl Source for Environment {
         };
 
         for (key, value) in env::vars() {
+            // Treat empty environment variables as unset
+            if cfg!(feature = "ignore-empty-env-vars") && value == "" {
+                continue;
+            }
+
             let mut key = key.to_string();
 
             // Check for prefix
diff --git a/tests/env.rs b/tests/env.rs
index 932d2fc..d1cb11a 100644
--- a/tests/env.rs
+++ b/tests/env.rs
@@ -60,3 +60,15 @@ fn test_separator_behavior() {
 
     env::remove_var("C_B_A");
 }
+
+#[test]
+#[cfg(feature = "ignore-empty-env-vars")]
+fn test_empty_value_is_ignored() {
+    env::set_var("C_A_B", "");
+
+    let environment = Environment::new();
+
+    assert!(!environment.collect().unwrap().contains_key("c_a_b"));
+
+    env::remove_var("C_A_B");
+}
-- 
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