[PATCH V4] update: warn if cwd was deleted

[Pierre-Yves David]

On 09/14/2016 05:05 PM, Stanislau Hlebik wrote:
> # HG changeset patch
> # User Stanislau Hlebik <stash at fb.com>
> # Date 1473865427 25200
> #      Wed Sep 14 08:03:47 2016 -0700
> # Node ID 84ef6a5bc6556f59ed8935a5f716be53a6e17951
> # Parent  f148bfa40489269be2e48046734f81065129847a
> update: warn if cwd was deleted
>
> During update directories are deleted as soon as they have no entries.
> But if current working directory is deleted then it cause problems
> in complex commands like 'hg split'. This commit adds a warning
> that will help users figure the problem faster.
>
> diff --git a/mercurial/merge.py b/mercurial/merge.py
> --- a/mercurial/merge.py
> +++ b/mercurial/merge.py
> @@ -1036,6 +1036,10 @@
>      unlink = util.unlinkpath
>      wjoin = repo.wjoin
>      audit = repo.wvfs.audit
> +    try:
> +        cwd = os.getcwd()
> +    except OSError:
> +        cwd = None

We should probably restrict this to actual directory removal error. The 
current code catch a wider familly of error and could lead to incorrect 
error reporting. The actual error code will be on the exception 'errno' 
attribut. See other usage of this in the codebade or Python 
documentation for details.

>      i = 0
>      for f, args, msg in actions:
>          repo.ui.debug(" %s: %s -> r\n" % (f, msg))
> @@ -1053,6 +1057,16 @@
>          i += 1
>      if i > 0:
>          yield i, f
> +    if cwd:
> +        # cwd was present before we started to remove files
> +        # let's check if it is present after we removed them
> +        try:
> +            os.getcwd()
> +        except OSError:
> +            # Print a warning if cwd was deleted
> +            repo.ui.warn(_("current directory was removed "
> +                           "(consider changing to repo root: %s)\n") %
> +                         repo.root)

Same thing apply here. I believe the error catching is too wide.

Also the hint (part in parenthesis) should be on another line to match 
our convention in error reporting.

Cheers,

-- 
Pierre-Yves David