D6441: help: check if a subtopic exists and raise an error if it doesn't (issue6145)

[ngoldbaum (Nathan Goldbaum)]

ngoldbaum added inline comments.

INLINE COMMENTS

> av6 wrote in help.py:689-695
> This made me remember that for-else statement exists.

I left this as-is because I find for-else statements hard to read (I never remember what it means!) and find this to be clearer even if there's a bit more boilerplate.

REPOSITORY
  rHG Mercurial

REVISION DETAIL
  https://phab.mercurial-scm.org/D6441

To: ngoldbaum, #hg-reviewers
Cc: av6, mercurial-devel