From dafa3b163f367086e470bb00faf26a67e9702310 Mon Sep 17 00:00:00 2001
From: Yuya Nishihara <yuya@tcha.org>
Date: Sat, 2 Nov 2024 10:57:05 +0900
Subject: [PATCH] cli: insert dummy -h/--help flag when parsing early args

Fixes #4746
---
 cli/src/cli_util.rs           |  9 +++++++++
 cli/tests/test_global_opts.rs | 10 ++++++++++
 2 files changed, 19 insertions(+)

diff --git a/cli/src/cli_util.rs b/cli/src/cli_util.rs
index 9f730d8bbf..8342fa8fec 100644
--- a/cli/src/cli_util.rs
+++ b/cli/src/cli_util.rs
@@ -3032,7 +3032,16 @@ fn handle_early_args(
     let early_matches = app
         .clone()
         .disable_version_flag(true)
+        // Do not emit DisplayHelp error
         .disable_help_flag(true)
+        // Do not stop parsing at -h/--help
+        .arg(
+            clap::Arg::new("help")
+                .short('h')
+                .long("help")
+                .global(true)
+                .action(ArgAction::Count),
+        )
         .ignore_errors(true)
         .try_get_matches_from(args)?;
     let mut args: EarlyArgs = EarlyArgs::from_arg_matches(&early_matches).unwrap();
diff --git a/cli/tests/test_global_opts.rs b/cli/tests/test_global_opts.rs
index c3eaf146d6..fc469e5414 100644
--- a/cli/tests/test_global_opts.rs
+++ b/cli/tests/test_global_opts.rs
@@ -559,6 +559,16 @@ fn test_early_args() {
     let stdout = test_env.jj_cmd_success(test_env.env_root(), &["help", "--color=always"]);
     insta::assert_snapshot!(stdout.lines().find(|l| l.contains("Commands:")).unwrap(), @"Commands:");
 
+    // Check that early args are accepted after -h/--help
+    let stdout = test_env.jj_cmd_success(test_env.env_root(), &["-h", "--color=always"]);
+    insta::assert_snapshot!(
+        stdout.lines().find(|l| l.contains("Usage:")).unwrap(),
+        @"Usage: jj [OPTIONS] <COMMAND>");
+    let stdout = test_env.jj_cmd_success(test_env.env_root(), &["log", "--help", "--color=always"]);
+    insta::assert_snapshot!(
+        stdout.lines().find(|l| l.contains("Usage:")).unwrap(),
+        @"Usage: jj log [OPTIONS] [PATHS]...");
+
     // Early args are parsed with clap's ignore_errors(), but there is a known
     // bug that causes defaults to be unpopulated. Test that the early args are
     // tolerant of this bug and don't cause a crash.