Bug: Windows guard in is_available() compares os.system (a function) to 'nt' — always False

Description

In httpie/output/ui/man_pages.py, is_available() tries to short-circuit on Windows but the check is broken:

https://github.com/httpie/cli/blob/master/httpie/output/ui/man_pages.py#L21

def is_available(program: str) -> bool:
    if NO_MAN_PAGES or os.system == 'nt':
        return False
    ...

os.system is a built-in function object, so os.system == 'nt' is always False. The intended Windows guard never fires. The author almost certainly meant os.name == 'nt'.

Why it is wrong

os.system is <built-in function system>; comparing a callable to the string 'nt' is always False.
The correct, idiomatic Windows check is os.name == 'nt' (or sys.platform == 'win32').

Impact

On Windows the if NO_MAN_PAGES or os.system == 'nt': branch is dead code. The function does not short-circuit; instead it falls through to subprocess.run(['man', '1', program]). On a typical Windows install man is absent, so FileNotFoundError is raised and swallowed by the except Exception: return False, yielding the same observable result — but only by accident. If a man executable happens to be on PATH (e.g. Git Bash / WSL), HTTPie will attempt to render man pages on Windows, contrary to the intent of the guard. Also, relying on a swallowed exception for control flow is fragile.

Reproduction / verification

import os
print(os.system == 'nt')   # -> False (regardless of platform)
print(os.name == 'nt')     # -> True on Windows, 'posix' elsewhere

Suggested fix

import sys
...
def is_available(program: str) -> bool:
    if NO_MAN_PAGES or sys.platform == 'win32':
        return False
    ...

(Using sys.platform == 'win32' is the most robust Windows detector.)

Affected version

Current master (verified via git clone --depth 1).

Follow-up: confirmed the bug — os.system is a built-in function object, so os.system == 'nt' is always False and the Windows short-circuit never fires (the function instead relies on a swallowed FileNotFoundError to return False by accident).

The intended guard should be a real platform check, e.g.:

import sys
...
def is_available(program: str) -> bool:
    if NO_MAN_PAGES or sys.platform == 'win32':
        return False
    ...

(sys.platform == 'win32' is the most robust Windows detector; os.name == 'nt' works too.)

Happy to open a PR that (1) swaps the guard for sys.platform == 'win32' and (2) adds a regression test asserting is_available() == (sys.platform == 'win32') so this can't silently regress again. Just let me know if you'd like me to send it.

fix: use sys.platform for Windows man page guard

Fix Windows guard in man page availability check

Fix Windows man pages guard: os.system to sys.platform

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Bug: Windows guard in is_available() compares os.system (a function) to 'nt' — always False #1898

Description

Why it is wrong

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Reproduction / verification

Suggested fix

Affected version

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Bug: Windows guard in is_available() compares os.system (a function) to 'nt' — always False #1898

Description

Description

Why it is wrong

Impact

Reproduction / verification

Suggested fix

Affected version

Activity

truongsontung commented on Jul 14, 2026

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