fix(commands): Require an argument name before the list of tracing filters when used without a subcommand (#7056)

* require flag for tracing filters when subcmd is omitted.

* Fixes test, updates Changelog

* Adds code comment

* Apply suggestions from code review

Co-authored-by: teor <teor@riseup.net>

---------

Co-authored-by: teor <teor@riseup.net>

CHANGELOG.md

@@ -6,6 +6,13 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org).
 
 
+## [Zebra 1.0.1](https://github.com/ZcashFoundation/zebra/releases/tag/v1.0.1) - 2023-XX-XX
+
+### Breaking Changes
+
+- Zebra now detects subcommand name typos on the command-line. If you want to give Zebra a list of tracing filters, use `zebrad start --filters debug,...` ([#7056](https://github.com/ZcashFoundation/zebra/pull/7056))
+
+
 ## [Zebra 1.0.1](https://github.com/ZcashFoundation/zebra/releases/tag/v1.0.1) - 2023-07-03
 
 Zebra's first patch release fixes multiple peer connection security issues and panics. It also significantly reduces Zebra's CPU usage. We recommend that all users upgrade to Zebra 1.0.1 or later.

zebrad/src/commands/entry_point.rs

@@ -1,7 +1,5 @@
 //! Zebrad EntryPoint
 
-use std::cmp::min;
-
 use abscissa_core::{Command, Configurable, FrameworkError, Runnable};
 use clap::Parser;
 use std::{ffi::OsString, path::PathBuf};
@@ -42,7 +40,7 @@ pub struct EntryPoint {
 
     /// Filter strings which override the config file and defaults
     // This can be applied to the default start command if no subcommand is provided.
-    #[clap(help = "tracing filters which override the zebrad.toml config")]
+    #[clap(long, help = "tracing filters which override the zebrad.toml config")]
     filters: Vec<String>,
 }
 
@@ -63,28 +61,23 @@ impl EntryPoint {
         "start"
     }
 
+    /// Checks if the provided arguments include a subcommand
+    fn should_add_default_subcommand(&self) -> bool {
+        self.cmd.is_none()
+    }
+
     /// Process command arguments and insert the default subcommand
     /// if no subcommand is provided.
     pub fn process_cli_args(mut args: Vec<OsString>) -> clap::error::Result<Vec<OsString>> {
-        // Check if the provided arguments include a subcommand
-        let should_add_default_subcommand = EntryPoint::try_parse_from(&args)?.cmd.is_none();
+        let entry_point = EntryPoint::try_parse_from(&args)?;
 
         // Add the default subcommand to args after the top-level args if cmd is None
-        if should_add_default_subcommand {
-            // try_parse_from currently produces an error if the first argument is not the binary name,
-            let mut num_top_level_args = 1;
-
-            // update last_top_level_arg_idx to the number of top-level args
-            for (idx, arg) in args.iter().enumerate() {
-                num_top_level_args = match arg.to_str() {
-                    Some("--verbose" | "-v" | "--version" | "-V" | "--help") => idx + 1,
-                    Some("--config" | "-c") => idx + 2,
-                    _ => num_top_level_args,
-                }
+        if entry_point.should_add_default_subcommand() {
+            args.push(EntryPoint::default_cmd_as_str().into());
+            // This duplicates the top-level filters args, but the tracing component only checks `StartCmd.filters`.
+            for filter in entry_point.filters {
+                args.push(filter.into())
             }
-
-            num_top_level_args = min(num_top_level_args, args.len());
-            args.insert(num_top_level_args, EntryPoint::default_cmd_as_str().into());
         }
 
         Ok(args)

zebrad/src/commands/tests.rs

@@ -16,7 +16,8 @@ fn args_with_subcommand_pass_through() {
         (true, false, false, vec!["zebrad", "--help"]),
         (false, true, false, vec!["zebrad", "start"]),
         (false, true, true, vec!["zebrad", "-v", "start"]),
-        (false, true, false, vec!["zebrad", "warn"]),
+        (false, true, false, vec!["zebrad", "--filters", "warn"]),
+        (true, false, false, vec!["zebrad", "warn"]),
         (false, true, false, vec!["zebrad", "start", "warn"]),
         (true, false, false, vec!["zebrad", "help", "warn"]),
     ];