Merge pull request #7918 from zimbatm/fix-empty-nix-store-env

treat empty NIX_STORE_DIR env vars as unset

2 files changed, 9 insertions, 0 deletions

diff --git a/src/libutil/util.cc b/src/libutil/util.cc
index e4af702a3..17ccf3554 100644
--- a/src/libutil/util.cc
+++ b/src/libutil/util.cc
@@ -54,6 +54,11 @@ std::optional<std::string> getEnv(const std::string & key)
     return std::string(value);
 }
 
+std::optional<std::string> getEnvNonEmpty(const std::string & key) {
+    auto value = getEnv(key);
+    if (value == "") return {};
+    return value;
+}
 
 std::map<std::string, std::string> getEnv()
 {
diff --git a/src/libutil/util.hh b/src/libutil/util.hh
index 75959d7e3..326c6b143 100644
--- a/src/libutil/util.hh
+++ b/src/libutil/util.hh
@@ -39,6 +39,10 @@ extern const std::string nativeSystem;
 /* Return an environment variable. */
 std::optional<std::string> getEnv(const std::string & key);
 
+/* Return a non empty environment variable. Returns nullopt if the env
+variable is set to "" */
+std::optional<std::string> getEnvNonEmpty(const std::string & key);
+
 /* Get the entire environment. */
 std::map<std::string, std::string> getEnv();