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dmach force-pushed the fix-argparse-subparser_all_mutually_exclusive_group_members_suppressed branch from 0d6958c to 616c5fe Compare August 26, 2022 13:52

Rationale
=========

argparse performs a complex formatting of the usage for argument grouping
and for line wrapping to fit the terminal width. This formatting has been
a constant source of bugs for at least 10 years (see linked issues below)
where defensive assertion errors are triggered or brackets and paranthesis
are not properly handeled.

Problem
=======

The current implementation of argparse usage formatting relies on regular
expressions to group arguments usage only to separate them again later
with another set of regular expressions. This is a complex and error prone
approach that caused all the issues linked below. Special casing certain
argument formats has not solved the problem. The following are some of
the most common issues:
- empty `metavar`
- mutually exclusive groups with `SUPPRESS`ed arguments
- metavars with whitespace
- metavars with brackets or paranthesis

Solution
========

The following two comments summarize the solution:
- python#82091 (comment)
- python#77048 (comment)

Mainly, the solution is to rewrite the usage formatting to avoid the
group-then-separate approach. Instead, the usage parts are kept separate
and only joined together at the end. This allows for a much simpler
implementation that is easier to understand and maintain. It avoids the
regular expressions approach and fixes the corresponding issues.

This closes the following issues:
- Closes python#62090
- Closes python#62549
- Closes python#77048
- Closes python#82091
- Closes python#89743
- Closes python#96310
- Closes python#98666

These PRs become obsolete:
- Closes python#15372
- Closes python#96311

serhiy-storchaka approved these changes Feb 21, 2024

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serhiy-storchaka enabled auto-merge (squash) February 21, 2024 13:36

…ually exclusive group are suppressed (pythonGH-96311)

Reproducer depends on terminal size - the traceback occurs when there's
an option long enough so the usage line doesn't fit the terminal width.
Option order is also important for reproducibility.

Excluding empty groups (with all options suppressed) from inserts
fixes the problem.
(cherry picked from commit 5f7df88)

Co-authored-by: Daniel Mach <[email protected]>

…ually exclusive group are suppressed (pythonGH-96311)

Reproducer depends on terminal size - the traceback occurs when there's
an option long enough so the usage line doesn't fit the terminal width.
Option order is also important for reproducibility.

Excluding empty groups (with all options suppressed) from inserts
fixes the problem.
(cherry picked from commit 5f7df88)

Co-authored-by: Daniel Mach <[email protected]>

…tually exclusive group are suppressed (GH-96311) (GH-115768)

Reproducer depends on terminal size - the traceback occurs when there's
an option long enough so the usage line doesn't fit the terminal width.
Option order is also important for reproducibility.

Excluding empty groups (with all options suppressed) from inserts
fixes the problem.
(cherry picked from commit 5f7df88)

Co-authored-by: Daniel Mach <[email protected]>

…tually exclusive group are suppressed (GH-96311) (GH-115767)

Reproducer depends on terminal size - the traceback occurs when there's
an option long enough so the usage line doesn't fit the terminal width.
Option order is also important for reproducibility.

Excluding empty groups (with all options suppressed) from inserts
fixes the problem.
(cherry picked from commit 5f7df88)

Co-authored-by: Daniel Mach <[email protected]>

…ually exclusive group are suppressed (pythonGH-96311)

Reproducer depends on terminal size - the traceback occurs when there's
an option long enough so the usage line doesn't fit the terminal width.
Option order is also important for reproducibility.

Excluding empty groups (with all options suppressed) from inserts
fixes the problem.

…ually exclusive group are suppressed (pythonGH-96311)

Reproducer depends on terminal size - the traceback occurs when there's
an option long enough so the usage line doesn't fit the terminal width.
Option order is also important for reproducibility.

Excluding empty groups (with all options suppressed) from inserts
fixes the problem.

Rationale
=========

argparse performs a complex formatting of the usage for argument grouping
and for line wrapping to fit the terminal width. This formatting has been
a constant source of bugs for at least 10 years (see linked issues below)
where defensive assertion errors are triggered or brackets and paranthesis
are not properly handeled.

Problem
=======

The current implementation of argparse usage formatting relies on regular
expressions to group arguments usage only to separate them again later
with another set of regular expressions. This is a complex and error prone
approach that caused all the issues linked below. Special casing certain
argument formats has not solved the problem. The following are some of
the most common issues:
- empty `metavar`
- mutually exclusive groups with `SUPPRESS`ed arguments
- metavars with whitespace
- metavars with brackets or paranthesis

Solution
========

The following two comments summarize the solution:
- #82091 (comment)
- #77048 (comment)

Mainly, the solution is to rewrite the usage formatting to avoid the
group-then-separate approach. Instead, the usage parts are kept separate
and only joined together at the end. This allows for a much simpler
implementation that is easier to understand and maintain. It avoids the
regular expressions approach and fixes the corresponding issues.

This closes the following GitHub issues:
-  #62090
-  #62549
-  #77048
-  #82091
-  #89743
-  #96310
-  #98666

These PRs become obsolete:
-  #15372
-  #96311

Rationale
=========

argparse performs a complex formatting of the usage for argument grouping
and for line wrapping to fit the terminal width. This formatting has been
a constant source of bugs for at least 10 years (see linked issues below)
where defensive assertion errors are triggered or brackets and paranthesis
are not properly handeled.

Problem
=======

The current implementation of argparse usage formatting relies on regular
expressions to group arguments usage only to separate them again later
with another set of regular expressions. This is a complex and error prone
approach that caused all the issues linked below. Special casing certain
argument formats has not solved the problem. The following are some of
the most common issues:
- empty `metavar`
- mutually exclusive groups with `SUPPRESS`ed arguments
- metavars with whitespace
- metavars with brackets or paranthesis

Solution
========

The following two comments summarize the solution:
- python#82091 (comment)
- python#77048 (comment)

Mainly, the solution is to rewrite the usage formatting to avoid the
group-then-separate approach. Instead, the usage parts are kept separate
and only joined together at the end. This allows for a much simpler
implementation that is easier to understand and maintain. It avoids the
regular expressions approach and fixes the corresponding issues.

This closes the following GitHub issues:
-  python#62090
-  python#62549
-  python#77048
-  python#82091
-  python#89743
-  python#96310
-  python#98666

These PRs become obsolete:
-  python#15372
-  python#96311

…ually exclusive group are suppressed (pythonGH-96311)

Reproducer depends on terminal size - the traceback occurs when there's
an option long enough so the usage line doesn't fit the terminal width.
Option order is also important for reproducibility.

Excluding empty groups (with all options suppressed) from inserts
fixes the problem.