support RCC_-prefixed env keys alongside legacy dotted keys

connections.env and local .env are transitioning from dotted keys
(ci.db.master.ip, connection) to upper-cased RCC_-prefixed keys
(RCC_CI_DB_MASTER_IP, RCC_CONNECTION). Both forms are matched and
toggled during the migration, so old branches keep working while
new ones use the new format.

src/config/parse.rs

@@ -44,12 +44,40 @@ pub fn set_dot_env(start: bool, config: &DevToolsConf) -> Result<()> {
     Ok(())
 }
 
+const CI_DB_MASTER_IP: &str = "ci.db.master.ip";
+const CI_DB_MASTER_PORT: &str = "ci.db.master.port";
+const CONNECTION: &str = "connection";
+
+const RCC_CI_DB_MASTER_IP: &str = "RCC_CI_DB_MASTER_IP";
+const RCC_CI_DB_MASTER_PORT: &str = "RCC_CI_DB_MASTER_PORT";
+const RCC_CONNECTION: &str = "RCC_CONNECTION";
+
+/// Converts a legacy dotted key (`ci.db.master.ip`) into its `RCC_`-prefixed
+/// replacement (`RCC_CI_DB_MASTER_IP`), as used by the new env file format.
+/// Test-only: keeps the `RCC_*` consts above honest (see `rcc_key_matches_const`)
+/// — the hot paths below use the consts directly to avoid allocating per line.
+#[cfg(test)]
+fn rcc_key(dotted_key: &str) -> String {
+    format!("RCC_{}", dotted_key.to_uppercase().replace('.', "_"))
+}
+
+fn starts_with_env_key(line: &str, key: &str) -> bool {
+    line.strip_prefix(key)
+        .is_some_and(|rest| rest.starts_with('='))
+}
+
 pub(crate) fn connections_env_comment(line: &str) -> bool {
-    line.starts_with("ci.db.master.ip=") || line.starts_with("ci.db.master.port=")
+    starts_with_env_key(line, CI_DB_MASTER_IP)
+        || starts_with_env_key(line, RCC_CI_DB_MASTER_IP)
+        || starts_with_env_key(line, CI_DB_MASTER_PORT)
+        || starts_with_env_key(line, RCC_CI_DB_MASTER_PORT)
 }
 
 pub(crate) fn should_commented_out(line: &str) -> bool {
-    line.starts_with("# ci.db.master.ip=") || line.starts_with("# ci.db.master.port=")
+    match line.strip_prefix("# ") {
+        Some(rest) => connections_env_comment(rest),
+        None => false,
+    }
 }
 
 fn toggle_after_line(
@@ -86,14 +114,10 @@ fn toggle_after_line(
         if relevant {
             modified_lines.push(toggle(&line_content, activate));
             counter += 1;
+        } else if let Some(key) = connection_key(&line_content) {
+            let value = if activate { "staging" } else { "ci" };
+            modified_lines.push(format!("{}='{}'", key, value));
         } else {
-            if !activate && line_content.trim_start().starts_with("connection=") {
-                modified_lines.push("connection='ci'".to_string());
-                continue;
-            } else if activate && line_content.trim_start().starts_with("connection=") {
-                modified_lines.push("connection='staging'".to_string());
-                continue;
-            }
             modified_lines.push(line_content);
         }
     }
@@ -104,6 +128,19 @@ fn toggle_after_line(
     Ok(())
 }
 
+/// Returns the `connection` key as it appears on the given line (either the
+/// legacy `connection` or the new `RCC_CONNECTION`), if the line sets it.
+fn connection_key(line: &str) -> Option<&'static str> {
+    let trimmed = line.trim_start();
+    if starts_with_env_key(trimmed, CONNECTION) {
+        Some(CONNECTION)
+    } else if starts_with_env_key(trimmed, RCC_CONNECTION) {
+        Some(RCC_CONNECTION)
+    } else {
+        None
+    }
+}
+
 pub(crate) fn toggle(line: &str, activate: bool) -> String {
     if activate {
         return line.replacen('#', "", 1);
@@ -169,4 +206,55 @@ mod tests {
     fn should_commented_out_ignores_uncommented() {
         assert!(!should_commented_out("ci.db.master.ip=127.0.0.1"));
     }
+
+    #[test]
+    fn rcc_key_converts_dotted_key() {
+        assert_eq!(rcc_key("ci.db.master.ip"), "RCC_CI_DB_MASTER_IP");
+        assert_eq!(rcc_key("connection"), "RCC_CONNECTION");
+    }
+
+    #[test]
+    fn rcc_key_matches_const() {
+        assert_eq!(rcc_key(CI_DB_MASTER_IP), RCC_CI_DB_MASTER_IP);
+        assert_eq!(rcc_key(CI_DB_MASTER_PORT), RCC_CI_DB_MASTER_PORT);
+        assert_eq!(rcc_key(CONNECTION), RCC_CONNECTION);
+    }
+
+    #[test]
+    fn connections_env_comment_matches_rcc_ip() {
+        assert!(connections_env_comment("RCC_CI_DB_MASTER_IP=127.0.0.1"));
+    }
+
+    #[test]
+    fn connections_env_comment_matches_rcc_port() {
+        assert!(connections_env_comment("RCC_CI_DB_MASTER_PORT=5432"));
+    }
+
+    #[test]
+    fn should_commented_out_matches_rcc_ip() {
+        assert!(should_commented_out("# RCC_CI_DB_MASTER_IP=127.0.0.1"));
+    }
+
+    #[test]
+    fn should_commented_out_matches_rcc_port() {
+        assert!(should_commented_out("# RCC_CI_DB_MASTER_PORT=5432"));
+    }
+
+    #[test]
+    fn connection_key_matches_legacy() {
+        assert_eq!(connection_key("connection='ci'"), Some("connection"));
+    }
+
+    #[test]
+    fn connection_key_matches_rcc() {
+        assert_eq!(
+            connection_key("RCC_CONNECTION='ci'"),
+            Some("RCC_CONNECTION")
+        );
+    }
+
+    #[test]
+    fn connection_key_ignores_other() {
+        assert_eq!(connection_key("connection_pool=5"), None);
+    }
 }