Re: [PATCH] Simplify handling of setup_git_directory_gently() failure cases.

[Erin Dahlgren <eedahlgren@gmail.com>]

On Fri, Dec 14, 2018 at 2:32 AM Johannes Schindelin
<Johannes.Schindelin@gmx.de> wrote:
>
> Hi Erin,
>
> On Thu, 13 Dec 2018, Erin Dahlgren wrote:
>
> > setup_git_directory_gently() expects two types of failures to
> > discover a git directory (e.g. .git/):
> >
> >   - GIT_DIR_HIT_CEILING: could not find a git directory in any
> >       parent directories of the cwd.
> >   - GIT_DIR_HIT_MOUNT_POINT: could not find a git directory in
> >       any parent directories up to the mount point of the cwd.
> >
> > Both cases are handled in a similar way, but there are misleading
> > and unimportant differences. In both cases, setup_git_directory_gently()
> > should:
> >
> >   - Die if we are not in a git repository. Otherwise:
> >   - Set nongit_ok = 1, indicating that we are not in a git repository
> >       but this is ok.
> >   - Call strbuf_release() on any non-static struct strbufs that we
> >       allocated.
> >
> > Before this change are two misleading additional behaviors:
> >
> >   - GIT_DIR_HIT_CEILING: setup_nongit() changes to the cwd for no
> >       apparent reason. We never had the chance to change directories
> >       up to this point so chdir(current cwd) is pointless.
> >   - GIT_DIR_HIT_MOUNT_POINT: strbuf_release() frees the buffer
> >       of a static struct strbuf (cwd). This is unnecessary because the
> >       struct is static so its buffer is always reachable. This is also
> >       misleading because nowhere else in the function is this buffer
> >       released.
> >
> > This change eliminates these two misleading additional behaviors and
> > deletes setup_nogit() because the code is clearer without it. The
> > result is that we can see clearly that GIT_DIR_HIT_CEILING and
> > GIT_DIR_HIT_MOUNT_POINT lead to the same behavior (ignoring the
> > different help messages).
> >
> > Thanks-to: Johannes Schindelin <johannes.schindelin@gmx.de>
> > Signed-off-by: Erin Dahlgren <eedahlgren@gmail.com>
>
> Thank you for working on this!
>
> > ---
> >  setup.c | 34 +++++++++++++---------------------
> >  1 file changed, 13 insertions(+), 21 deletions(-)
>
> Nice! It's always good to see a code reduction with such a cleanup.
>
> Just one thing:
>
> > diff --git a/setup.c b/setup.c
> > index 1be5037..b441e39 100644
> > --- a/setup.c
> > +++ b/setup.c
> > @@ -831,16 +831,6 @@ static const char *setup_bare_git_dir(struct strbuf *cwd, int offset,
> >       return NULL;
> >  }
> >
> > -static const char *setup_nongit(const char *cwd, int *nongit_ok)
> > -{
> > -     if (!nongit_ok)
> > -             die(_("not a git repository (or any of the parent directories): %s"), DEFAULT_GIT_DIR_ENVIRONMENT);
> > -     if (chdir(cwd))
> > -             die_errno(_("cannot come back to cwd"));
> > -     *nongit_ok = 1;
> > -     return NULL;
> > -}
> > -
> >  static dev_t get_device_or_die(const char *path, const char *prefix, int prefix_len)
> >  {
> >       struct stat buf;
> > @@ -1097,18 +1087,20 @@ const char *setup_git_directory_gently(int *nongit_ok)
> >               prefix = setup_bare_git_dir(&cwd, dir.len, &repo_fmt, nongit_ok);
> >               break;
> >       case GIT_DIR_HIT_CEILING:
> > -             prefix = setup_nongit(cwd.buf, nongit_ok);
> > -             break;
> > +             if (!nongit_ok)
> > +                     die(_("not a git repository (or any of the parent directories): %s"),
> > +                                     DEFAULT_GIT_DIR_ENVIRONMENT);
> > +             *nongit_ok = 1;
> > +             strbuf_release(&dir);
> > +             return NULL;
> >       case GIT_DIR_HIT_MOUNT_POINT:
> > -             if (nongit_ok) {
> > -                     *nongit_ok = 1;
> > -                     strbuf_release(&cwd);
> > -                     strbuf_release(&dir);
> > -                     return NULL;
> > -             }
> > -             die(_("not a git repository (or any parent up to mount point %s)\n"
> > -                   "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set)."),
> > -                 dir.buf);
> > +             if (!nongit_ok)
> > +                     die(_("not a git repository (or any parent up to mount point %s)\n"
> > +                                             "Stopping at filesystem boundary (GIT_DISCOVERY_ACROSS_FILESYSTEM not set)."),
> > +                                     dir.buf);
>
> This indentation would probably be better aligned with the first
> double-quote on the `die` line.

Hi Johannes,

No problem. Thanks for your time discussing and reviewing!

- Erin

>
> Otherwise: ACK!
>
> Thank you,
> Johannes
>
> > +             *nongit_ok = 1;
> > +             strbuf_release(&dir);
> > +             return NULL;
> >       default:
> >               BUG("unhandled setup_git_directory_1() result");
> >       }
> > --
> > 2.7.4
> >
> >