Rename .gitignore APP_FOO to ARTI_FOO.

Since these shell-variables are hardwired to use org.torproject.Arti as
the program name, it isn't appropriate to call them "app-specific".

If we someday reinstate APP_FOO, it should be based on a user-provided
application name.

crates/arti-client/src/config.rs

@@ -171,7 +171,7 @@ impl TorClientConfig {
     /// Returns a `TorClientConfig` using reasonably sane defaults.
     ///
     /// This gies the same result as using `tor_config`'s definitions
-    /// for `APP_LOCAL_DATA` and `APP_CACHE` for the state and cache
+    /// for `ARTI_LOCAL_DATA` and `ARTI_CACHE` for the state and cache
     /// directories respectively.
     ///
     /// (On unix, this usually works out to `~/.local/share/arti` and

crates/arti-config/src/arti_defaults.toml

@@ -32,16 +32,16 @@ trace_filter = "debug"
 # These paths can use ~ to indicate the user's home directory, or a set
 # of shell-style variables to indicate platform-specific paths.
 #
-# Supported variables are APP_CACHE, APP_CONFIG, APP_SHARED_DATA,
-# APP_LOCAL_DATA, and USER_HOME.
+# Supported variables are ARTI_CACHE, ARTI_CONFIG, ARTI_SHARED_DATA,
+# ARTI_LOCAL_DATA, and USER_HOME.
 #
 # Multiple processes can share the same cache_dir.  If they do, one of them
 # will download directory information for all of the others.
 #
 # The state directory is not yet used.
 [storage]
-cache_dir = "${APP_CACHE}"
-state_dir = "${APP_LOCAL_DATA}"
+cache_dir = "${ARTI_CACHE}"
+state_dir = "${ARTI_LOCAL_DATA}"
 
 # Replacement values for consensus parameters.  This is an advanced option
 # and you probably should leave it alone. Not all parameters are supported.

crates/arti-config/src/lib.rs

@@ -91,7 +91,7 @@ fn load_mut<P: AsRef<Path>>(
 
 /// Return a filename for the default user configuration file.
 pub fn default_config_file() -> Option<PathBuf> {
-    CfgPath::new("${APP_CONFIG}/arti.toml".into()).path().ok()
+    CfgPath::new("${ARTI_CONFIG}/arti.toml".into()).path().ok()
 }
 
 #[cfg(test)]

crates/tor-config/src/path.rs

@@ -13,11 +13,11 @@ use serde::Deserialize;
 /// with expansion of certain variables.
 ///
 /// The supported variables are:
-///   * `APP_CACHE`: an arti-specific cache directory.
-///   * `APP_CONFIG`: an arti-specific configuration directory.
-///   * `APP_SHARED_DATA`: an arti-specific directory in the user's "shared
+///   * `ARTI_CACHE`: an arti-specific cache directory.
+///   * `ARTI_CONFIG`: an arti-specific configuration directory.
+///   * `ARTI_SHARED_DATA`: an arti-specific directory in the user's "shared
 ///     data" space.
-///   * `APP_LOCAL_DATA`: an arti-specific directory in the user's "local
+///   * `ARTI_LOCAL_DATA`: an arti-specific directory in the user's "local
 ///     data" space.
 ///   * `USER_HOME`: the user's home directory.
 ///
@@ -108,10 +108,10 @@ fn get_home() -> Option<&'static Path> {
 #[cfg(feature = "expand-paths")]
 fn get_env(var: &str) -> Result<Option<&'static str>, CfgPathError> {
     let path = match var {
-        "APP_CACHE" => project_dirs()?.cache_dir(),
-        "APP_CONFIG" => project_dirs()?.config_dir(),
-        "APP_SHARED_DATA" => project_dirs()?.data_dir(),
-        "APP_LOCAL_DATA" => project_dirs()?.data_local_dir(),
+        "ARTI_CACHE" => project_dirs()?.cache_dir(),
+        "ARTI_CONFIG" => project_dirs()?.config_dir(),
+        "ARTI_SHARED_DATA" => project_dirs()?.data_dir(),
+        "ARTI_LOCAL_DATA" => project_dirs()?.data_local_dir(),
         "USER_HOME" => base_dirs()?.home_dir(),
         _ => return Err(CfgPathError::UnknownVar(var.to_owned())),
     };
@@ -188,8 +188,8 @@ mod test {
 
     #[test]
     fn expand_cache() {
-        let p = CfgPath::new("${APP_CACHE}/example".to_string());
-        assert_eq!(p.to_string(), "${APP_CACHE}/example".to_string());
+        let p = CfgPath::new("${ARTI_CACHE}/example".to_string());
+        assert_eq!(p.to_string(), "${ARTI_CACHE}/example".to_string());
 
         let expected = project_dirs().unwrap().cache_dir().join("example");
         assert_eq!(p.path().unwrap().to_str(), expected.to_str());
@@ -197,8 +197,8 @@ mod test {
 
     #[test]
     fn expand_bogus() {
-        let p = CfgPath::new("${APP_WOMBAT}/example".to_string());
-        assert_eq!(p.to_string(), "${APP_WOMBAT}/example".to_string());
+        let p = CfgPath::new("${ARTI_WOMBAT}/example".to_string());
+        assert_eq!(p.to_string(), "${ARTI_WOMBAT}/example".to_string());
 
         assert!(p.path().is_err());
     }