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authorEelco Dolstra <edolstra@gmail.com>2019-11-22T15·06+0100
committerglittershark <grfn@gws.fyi>2020-09-01T02·21+0000
commit785cb3a75476033ba6eec2fef334d47d8e64388a (patch)
tree676d53868e29e0ab28443b9d13019c54754012f7 /third_party/nix/src/libutil/util.hh
parentc5f3b12f0484cd1a5152b6c64a336e9852d7c484 (diff)
refactor(tvix): getEnv(): Return std::optional r/1756
This allows distinguishing between an empty value and no value.

Patch ported from upstream at
https://github.com/NixOS/nix/commit/ba87b08f8529e4d9f8c58d8c625152058ceadb75

Change-Id: I061cc8e16b1a7a0341adfc3b0edca1c0c51d5c97
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1884
Tested-by: BuildkiteCI
Reviewed-by: kanepyork <rikingcoding@gmail.com>
Diffstat (limited to 'third_party/nix/src/libutil/util.hh')
-rw-r--r--third_party/nix/src/libutil/util.hh2
1 files changed, 1 insertions, 1 deletions
diff --git a/third_party/nix/src/libutil/util.hh b/third_party/nix/src/libutil/util.hh
index b6d726b46c01..b3349c4f39c4 100644
--- a/third_party/nix/src/libutil/util.hh
+++ b/third_party/nix/src/libutil/util.hh
@@ -26,7 +26,7 @@ struct Source;
 extern const std::string nativeSystem;
 
 /* Return an environment variable. */
-std::string getEnv(const std::string& key, const std::string& def = "");
+std::optional<std::string> getEnv(const std::string& key);
 
 /* Get the entire environment. */
 std::map<std::string, std::string> getEnv();