fix config from env var

.changelog/unreleased/bug-fixes/3971-fix-config-from-env.md

@@ -0,0 +1,3 @@
+- Fix the prefix separator for config key-vals set from env var to a
+  single underscore between the "NAMADA" prefix and the rest of the path.
+  ([\#3971](https://github.com/anoma/namada/pull/3971))

Cargo.toml

@@ -93,7 +93,7 @@ clap_complete_nushell = "4.5"
 clru = {git = "https://github.com/marmeladema/clru-rs.git", rev = "71ca566"}
 color-eyre = "0.6.2"
 concat-idents = "1.1.2"
-config = { git = "https://github.com/mehcode/config-rs.git", rev = "e3c1d0b452639478662a44f15ef6d5b6d969bf9b" }
+config = "0.14.1"
 data-encoding = "2.3.2"
 derivation-path = "0.2.0"
 derivative = "2.2.0"

crates/apps_lib/src/config/mod.rs

@@ -287,7 +287,9 @@ impl Config {
             .add_source(defaults)
             .add_source(config::File::with_name(file_name))
             .add_source(
-                config::Environment::with_prefix("NAMADA").separator("__"),
+                config::Environment::with_prefix("NAMADA")
+                    .prefix_separator("_")
+                    .separator("__"),
             );
 
         let config = builder.build().map_err(Error::ReadError)?;
@@ -854,11 +856,38 @@ namespace = "cometbft"
 
 #[cfg(test)]
 mod tests {
-    use super::DEFAULT_COMETBFT_CONFIG;
+    use std::env;
+
+    use namada_sdk::chain::ChainId;
+    use tempfile::tempdir;
+
+    use super::{Config, DEFAULT_COMETBFT_CONFIG};
+    use crate::config::TendermintMode;
     use crate::tendermint_config::TendermintConfig;
 
     #[test]
     fn test_default_cometbft_config() {
         assert!(TendermintConfig::parse_toml(DEFAULT_COMETBFT_CONFIG).is_ok());
     }
+
+    /// Check that a key-val set from an env var gets applied to a loaded config
+    #[test]
+    fn test_config_env_var() {
+        let base_dir = tempdir().unwrap();
+        let chain_id = ChainId("ChainyMcChainFace".to_owned());
+
+        Config::generate(
+            base_dir.path(),
+            &chain_id,
+            TendermintMode::Full,
+            true,
+        )
+        .unwrap();
+
+        let moniker = "moniker_from_env";
+        env::set_var("NAMADA_LEDGER__COMETBFT__MONIKER", moniker);
+        let config = Config::load(&base_dir, &chain_id, None);
+
+        assert_eq!(config.ledger.cometbft.moniker.as_ref(), moniker);
+    }
 }