Merge branch 'trs/fix-help-all-on-≥3.10'

CHANGES.md

@@ -21,6 +21,14 @@ development source code and as such may not be routinely kept up to date.
   `{files}`.
   ([#260](https://github.com/nextstrain/cli/pull/260))
 
+* When running on Python ≥3.10, the `--help` output of `nextstrain build`,
+  `nextstrain view`, and `nextstrain shell` once again shows just the most
+  common options.  All options are still shown with `--help-all`.  A regression
+  since Python 3.10 meant that `--help` acted the same as `--help-all` before
+  this fix.  This affected any installation on Python ≥3.10, including
+  standalone installations, since the standalone binaries bundle Python 3.10.
+  ([#259](https://github.com/nextstrain/cli/pull/259))
+
 
 # 6.1.0.post1 (18 January 2023)
 

nextstrain/cli/argparse.py

@@ -1,6 +1,7 @@
 """
 Custom helpers for extending the behaviour of argparse standard library.
 """
+import sys
 from argparse import Action, ArgumentDefaultsHelpFormatter, ArgumentTypeError, SUPPRESS
 from itertools import takewhile
 from textwrap import indent
@@ -113,9 +114,13 @@ def __call__(self, parser, namespace, values, option_string = None):
 
     def truncate_help(self, full_help):
         """
-        Truncate the full help after the standard "optional arguments" listing
-        and before any custom argument groups.
+        Truncate the full help after the standard "options" (or "optional
+        arguments") listing and before any custom argument groups.
         """
+        # See <https://github.com/python/cpython/pull/23858>
+        # and <https://bugs.python.org/issue9694>.
+        heading = "options:\n" if sys.version_info >= (3, 10) else "optional arguments:\n"
+
         seen_optional_arguments_heading = False
 
         def before_extra_argument_groups(line):
@@ -127,7 +132,7 @@ def before_extra_argument_groups(line):
             nonlocal seen_optional_arguments_heading
 
             if not seen_optional_arguments_heading:
-                if line == "optional arguments:\n":
+                if line == heading:
                     seen_optional_arguments_heading = True
 
             return not seen_optional_arguments_heading \