[PATCH 2/4] dts: customise argparse error message

[Luca Vizzarro <luca.vizzarro@arm.com>]

This commit customises the arguments parsing class' error message,
making it so the confusing usage is not displayed in these occurrences,
but the user is redirected to use the help argument instead.

Reviewed-by: Paul Szczepanek <paul.szczepanek@arm.com>
Signed-off-by: Luca Vizzarro <luca.vizzarro@arm.com>
---
 dts/framework/settings.py | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/dts/framework/settings.py b/dts/framework/settings.py
index 2d0365e763..acfe5cad44 100644
--- a/dts/framework/settings.py
+++ b/dts/framework/settings.py
@@ -170,6 +170,15 @@ def _parse_revision_id(rev_id: str) -> str:
         )
 
 
+class ArgumentParser(argparse.ArgumentParser):
+    """ArgumentParser with a custom error message."""
+    def error(self, message):
+        print(f"{self.prog}: error: {message}\n", file=sys.stderr)
+        self.exit(2,
+                  "For help and usage, "
+                  "run the command with the --help flag.\n")
+
+
 @dataclass(slots=True)
 class Settings:
     """Default framework-wide user settings.
@@ -200,8 +209,8 @@ class Settings:
 SETTINGS: Settings = Settings()
 
 
-def _get_parser() -> argparse.ArgumentParser:
-    parser = argparse.ArgumentParser(
+def _get_parser() -> ArgumentParser:
+    parser = ArgumentParser(
         description="Run DPDK test suites. All options may be specified with the environment "
         "variables provided in brackets. Command line arguments have higher priority.",
         formatter_class=argparse.ArgumentDefaultsHelpFormatter,
-- 
2.34.1