Allow config files to be specified anywhere in the command.

Sadly, we need to work around clap's limitations to do it,
which results in suboptmial error messages if these arguments
are missing. Basically we pretend to clap that they're optional
and check if they're provided manually.

hyperspace/core/src/command.rs

@@ -64,34 +64,42 @@ pub enum Subcommand {
 	},
 }
 
+/* Notice that config_a, config_b and config_core are optional below,
+   even though we consider them mandatory. This is due to limitations
+   of clap, which does not allow mandatory arguments to be global.
+   Being local, they would have to occur immediately after query
+   subcommand, which is not very user-friendly. For this reason we
+   tell clap they're optional and raise an error later if they are not
+   provided.
+*/
 #[derive(Debug, Clone, Parser)]
 pub struct Cmd {
-	/// Relayer chain A config path.
-	#[clap(long)]
-	pub config_a: String,
-	/// Relayer chain B config path.
-	#[clap(long)]
-	config_b: String,
-	/// Relayer core config path.
-	#[clap(long)]
-	config_core: String,
+	/// Relayer chain A config path (madatory).
+	#[clap(long, global = true)]
+	pub config_a: Option<String>,
+	/// Relayer chain B config path (mandatory).
+	#[clap(long, global = true)]
+	config_b: Option<String>,
+    /// Relayer core config path (mandatory).
+	#[clap(long, global = true)]
+	config_core: Option<String>,
 	/// Port id for channel creation
-	#[clap(long)]
+	#[clap(long, global = true)]
 	port_id: Option<String>,
 	/// Connection delay period in seconds
-	#[clap(long)]
+	#[clap(long, global = true)]
 	delay_period: Option<std::num::NonZeroU32>,
 	/// Channel order
-	#[clap(long)]
+	#[clap(long, global = true)]
 	order: Option<String>,
 	/// Channel version
-	#[clap(long)]
+	#[clap(long, global = true)]
 	version: Option<String>,
 	/// New config path for A to avoid overriding existing configuration
-	#[clap(long)]
+	#[clap(long, global = true)]
 	pub out_config_a: Option<String>,
 	/// New config path for B to avoid overriding existing configuration
-	#[clap(long)]
+	#[clap(long, global = true)]
 	pub out_config_b: Option<String>,
 }
 
@@ -132,9 +140,15 @@ impl UploadWasmCmd {
 impl Cmd {
 	pub async fn parse_config(&self) -> Result<Config> {
 		use tokio::fs::read_to_string;
-		let path_a: PathBuf = self.config_a.parse()?;
-		let path_b: PathBuf = self.config_b.parse()?;
-		let path_core: PathBuf = self.config_core.parse()?;
+		let config_a_opt =
+			self.config_a.clone().ok_or(anyhow::anyhow!("--config-a is mandatory"))?;
+		let path_a: PathBuf = config_a_opt.parse()?;
+		let config_b_opt =
+			self.config_b.clone().ok_or(anyhow::anyhow!("--config-b is mandatory"))?;
+		let path_b: PathBuf = config_b_opt.parse()?;
+		let config_core_opt =
+			self.config_core.clone().ok_or(anyhow::anyhow!("--config-core is mandatory"))?;
+		let path_core: PathBuf = config_core_opt.parse()?;
 		let file_content = read_to_string(path_a).await?;
 		let config_a: AnyConfig = toml::from_str(&file_content)?;
 		let file_content = read_to_string(path_b).await?;
@@ -279,8 +293,10 @@ impl Cmd {
 	}
 
 	pub async fn save_config(&self, new_config: &Config) -> Result<()> {
-		let path_a = self.out_config_a.as_ref().cloned().unwrap_or_else(|| self.config_a.clone());
-		let path_b = self.out_config_b.as_ref().cloned().unwrap_or_else(|| self.config_b.clone());
+		let path_a = self.out_config_a.as_ref().cloned().or_else(|| self.config_a.clone())
+            .ok_or(anyhow::anyhow!("--config-a is mandatory"))?;
+		let path_b = self.out_config_b.as_ref().cloned().or_else(|| self.config_b.clone())
+            .ok_or(anyhow::anyhow!("--config-b is mandatory"))?;
 		write_config(path_a, &new_config.chain_a).await?;
 		write_config(path_b, &new_config.chain_b).await
 	}