| Message ID | 7b0c665fb75d3d73d9d8d03b629a09a0ec4244e6.1637455620.git.gitgitgadget@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Avoid removing the current working directory, even if it becomes empty | expand |
"Elijah Newren via GitGitGadget" <gitgitgadget@gmail.com> writes: > From: Elijah Newren <newren@gmail.com> > > Removing the current working directory causes all subsequent git > commands (and likely a number of non-git commands) run from that > directory to get confused and fail with a message about being unable to > read the current working directory. That confuses end users, > particularly since the command they get the error from is not the one > that caused the problem; the problem came from the side-effect of some > previous command. > > We would like to avoid removing the current working directory; towards > this end, introduce a new the_cwd variable that tracks the current > working directory. Subsequent commits will make use of this new > variable. Maybe a stupid question, but how is this different from doing getcwd() and storing it away to the_cwd, or adding a check to see if the directory we are about to rmdir() is the cwd, next to the existing check that we do to see if that directory has some untracked files? I am wondering how we are going to make sure that the_cwd is always set to, and maintained to be, the correct value, even in the future when these code paths change. I also wonder if it might be safer to learn what the value of cwd is very near the place where it will become needed (i.e. the callsites of such rmdir() of a directory inside working tree), instead of caching. > Signed-off-by: Elijah Newren <newren@gmail.com> > --- > repository.c | 1 + > repository.h | 1 + > setup.c | 2 ++ > 3 files changed, 4 insertions(+) > > diff --git a/repository.c b/repository.c > index c5b90ba93ea..69a106c553c 100644 > --- a/repository.c > +++ b/repository.c > @@ -17,6 +17,7 @@ > static struct repository the_repo; > struct repository *the_repository; > struct index_state the_index; > +char *the_cwd; > > void initialize_the_repository(void) > { > diff --git a/repository.h b/repository.h > index a057653981c..45de85d18ef 100644 > --- a/repository.h > +++ b/repository.h > @@ -147,6 +147,7 @@ struct repository { > }; > > extern struct repository *the_repository; > +extern char *the_cwd; > > /* > * Define a custom repository layout. Any field can be NULL, which > diff --git a/setup.c b/setup.c > index 347d7181ae9..4466fa55af3 100644 > --- a/setup.c > +++ b/setup.c > @@ -887,6 +887,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv, > set_git_dir(gitdirenv, 1); > if (chdir(worktree)) > die_errno(_("cannot chdir to '%s'"), worktree); > + the_cwd = xstrdup(cwd->buf + offset); > strbuf_addch(cwd, '/'); > free(gitfile); > return cwd->buf + offset; > @@ -940,6 +941,7 @@ static const char *setup_discovered_git_dir(const char *gitdir, > /* Make "offset" point past the '/' (already the case for root dirs) */ > if (offset != offset_1st_component(cwd->buf)) > offset++; > + the_cwd = xstrdup(cwd->buf + offset); > /* Add a '/' at the end */ > strbuf_addch(cwd, '/'); > return cwd->buf + offset;
Am 21.11.21 um 01:46 schrieb Elijah Newren via GitGitGadget: > From: Elijah Newren <newren@gmail.com> > > Removing the current working directory causes all subsequent git > commands (and likely a number of non-git commands) run from that > directory to get confused and fail with a message about being unable to > read the current working directory. That confuses end users, > particularly since the command they get the error from is not the one > that caused the problem; the problem came from the side-effect of some > previous command. > > We would like to avoid removing the current working directory; A worthy goal. > towards > this end, introduce a new the_cwd variable that tracks the current > working directory. Subsequent commits will make use of this new > variable. Why make it a global variable instead of getting the working directory in the places that try to delete directories? (Honest question, not a suggestion.) > > Signed-off-by: Elijah Newren <newren@gmail.com> > --- > repository.c | 1 + > repository.h | 1 + > setup.c | 2 ++ > 3 files changed, 4 insertions(+) > > diff --git a/repository.c b/repository.c > index c5b90ba93ea..69a106c553c 100644 > --- a/repository.c > +++ b/repository.c > @@ -17,6 +17,7 @@ > static struct repository the_repo; > struct repository *the_repository; > struct index_state the_index; > +char *the_cwd; > > void initialize_the_repository(void) > { > diff --git a/repository.h b/repository.h > index a057653981c..45de85d18ef 100644 > --- a/repository.h > +++ b/repository.h > @@ -147,6 +147,7 @@ struct repository { > }; > > extern struct repository *the_repository; > +extern char *the_cwd; > > /* > * Define a custom repository layout. Any field can be NULL, which > diff --git a/setup.c b/setup.c > index 347d7181ae9..4466fa55af3 100644 > --- a/setup.c > +++ b/setup.c > @@ -887,6 +887,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv, > set_git_dir(gitdirenv, 1); > if (chdir(worktree)) > die_errno(_("cannot chdir to '%s'"), worktree); > + the_cwd = xstrdup(cwd->buf + offset); > strbuf_addch(cwd, '/'); > free(gitfile); > return cwd->buf + offset; > @@ -940,6 +941,7 @@ static const char *setup_discovered_git_dir(const char *gitdir, > /* Make "offset" point past the '/' (already the case for root dirs) */ > if (offset != offset_1st_component(cwd->buf)) > offset++; > + the_cwd = xstrdup(cwd->buf + offset); > /* Add a '/' at the end */ > strbuf_addch(cwd, '/'); > return cwd->buf + offset; >
On Sun, Nov 21, 2021 at 12:00 AM Junio C Hamano <gitster@pobox.com> wrote: > > "Elijah Newren via GitGitGadget" <gitgitgadget@gmail.com> writes: > > > From: Elijah Newren <newren@gmail.com> > > > > Removing the current working directory causes all subsequent git > > commands (and likely a number of non-git commands) run from that > > directory to get confused and fail with a message about being unable to > > read the current working directory. That confuses end users, > > particularly since the command they get the error from is not the one > > that caused the problem; the problem came from the side-effect of some > > previous command. > > > > We would like to avoid removing the current working directory; towards > > this end, introduce a new the_cwd variable that tracks the current > > working directory. Subsequent commits will make use of this new > > variable. > > Maybe a stupid question, but how is this different from doing getcwd() > and storing it away to the_cwd The exact output of getcwd() is an absolute path, whereas it's easier to perform later checks if we have a path that is relative to the toplevel working directory. Also, setup.c already calls getcwd() (via strbuf_getcwd()) and then massages it, and I'd have to do the exact same type of massaging. So, instead of calling getcwd() again and re-massaging its output into the format I want, I just reuse the existing call of getcwd() and its massaged output. > or adding a check to see if the > directory we are about to rmdir() is the cwd, next to the existing > check that we do to see if that directory has some untracked files? > > I am wondering how we are going to make sure that the_cwd is always > set to, and maintained to be, the correct value, even in the future > when these code paths change. I also wonder if it might be safer to > learn what the value of cwd is very near the place where it will > become needed (i.e. the callsites of such rmdir() of a directory > inside working tree), instead of caching. I need to clean up my wording a bit, to clarify this. Doing as you suggest here would protect the wrong thing. git has long done an automatic chdir() at startup to the toplevel working tree, whereas what we want to protect is the original current working directory as of the time git started. The original current working directory is likely also still the current working directory of the parent process that spawned us, and if that parent process is a shell, any subsequent commands executed from there can be somewhat confusing when its current working directory is removed. > > Signed-off-by: Elijah Newren <newren@gmail.com> > > --- > > repository.c | 1 + > > repository.h | 1 + > > setup.c | 2 ++ > > 3 files changed, 4 insertions(+) > > > > diff --git a/repository.c b/repository.c > > index c5b90ba93ea..69a106c553c 100644 > > --- a/repository.c > > +++ b/repository.c > > @@ -17,6 +17,7 @@ > > static struct repository the_repo; > > struct repository *the_repository; > > struct index_state the_index; > > +char *the_cwd; > > > > void initialize_the_repository(void) > > { > > diff --git a/repository.h b/repository.h > > index a057653981c..45de85d18ef 100644 > > --- a/repository.h > > +++ b/repository.h > > @@ -147,6 +147,7 @@ struct repository { > > }; > > > > extern struct repository *the_repository; > > +extern char *the_cwd; > > > > /* > > * Define a custom repository layout. Any field can be NULL, which > > diff --git a/setup.c b/setup.c > > index 347d7181ae9..4466fa55af3 100644 > > --- a/setup.c > > +++ b/setup.c > > @@ -887,6 +887,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv, > > set_git_dir(gitdirenv, 1); > > if (chdir(worktree)) > > die_errno(_("cannot chdir to '%s'"), worktree); > > + the_cwd = xstrdup(cwd->buf + offset); > > strbuf_addch(cwd, '/'); > > free(gitfile); > > return cwd->buf + offset; > > @@ -940,6 +941,7 @@ static const char *setup_discovered_git_dir(const char *gitdir, > > /* Make "offset" point past the '/' (already the case for root dirs) */ > > if (offset != offset_1st_component(cwd->buf)) > > offset++; > > + the_cwd = xstrdup(cwd->buf + offset); > > /* Add a '/' at the end */ > > strbuf_addch(cwd, '/'); > > return cwd->buf + offset;
On Sun, Nov 21, 2021 at 12:56 AM René Scharfe <l.s.r@web.de> wrote: > > Am 21.11.21 um 01:46 schrieb Elijah Newren via GitGitGadget: > > From: Elijah Newren <newren@gmail.com> > > > > Removing the current working directory causes all subsequent git > > commands (and likely a number of non-git commands) run from that > > directory to get confused and fail with a message about being unable to > > read the current working directory. That confuses end users, > > particularly since the command they get the error from is not the one > > that caused the problem; the problem came from the side-effect of some > > previous command. > > > > We would like to avoid removing the current working directory; > > A worthy goal. > > > towards > > this end, introduce a new the_cwd variable that tracks the current > > working directory. Subsequent commits will make use of this new > > variable. > > Why make it a global variable instead of getting the working directory > in the places that try to delete directories? (Honest question, not a > suggestion.) As I mentioned in my response to Junio, I need to be clearer that what I want to protect is the current working directory as of the startup of the git process, as a proxy for the current working directory of the parent process, so that subsequent commands started from the parent process don't get confused. As such, we don't want to get the working directory again later, because that'd give us the wrong thing. Also, setup.c has some nice massaging of getcwd() from an absolute path into a relative path that is much more convenient for us to do our later comparisons, and we'd rather not do those additional tweaks with every check. Since the relative path from the project root to the _original_ current working directory is a single value, a global seemed to make sense for saving it. Perhaps I should tweak it to be const as well. > > > > > Signed-off-by: Elijah Newren <newren@gmail.com> > > --- > > repository.c | 1 + > > repository.h | 1 + > > setup.c | 2 ++ > > 3 files changed, 4 insertions(+) > > > > diff --git a/repository.c b/repository.c > > index c5b90ba93ea..69a106c553c 100644 > > --- a/repository.c > > +++ b/repository.c > > @@ -17,6 +17,7 @@ > > static struct repository the_repo; > > struct repository *the_repository; > > struct index_state the_index; > > +char *the_cwd; > > > > void initialize_the_repository(void) > > { > > diff --git a/repository.h b/repository.h > > index a057653981c..45de85d18ef 100644 > > --- a/repository.h > > +++ b/repository.h > > @@ -147,6 +147,7 @@ struct repository { > > }; > > > > extern struct repository *the_repository; > > +extern char *the_cwd; > > > > /* > > * Define a custom repository layout. Any field can be NULL, which > > diff --git a/setup.c b/setup.c > > index 347d7181ae9..4466fa55af3 100644 > > --- a/setup.c > > +++ b/setup.c > > @@ -887,6 +887,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv, > > set_git_dir(gitdirenv, 1); > > if (chdir(worktree)) > > die_errno(_("cannot chdir to '%s'"), worktree); > > + the_cwd = xstrdup(cwd->buf + offset); > > strbuf_addch(cwd, '/'); > > free(gitfile); > > return cwd->buf + offset; > > @@ -940,6 +941,7 @@ static const char *setup_discovered_git_dir(const char *gitdir, > > /* Make "offset" point past the '/' (already the case for root dirs) */ > > if (offset != offset_1st_component(cwd->buf)) > > offset++; > > + the_cwd = xstrdup(cwd->buf + offset); > > /* Add a '/' at the end */ > > strbuf_addch(cwd, '/'); > > return cwd->buf + offset; > > >
diff --git a/repository.c b/repository.c index c5b90ba93ea..69a106c553c 100644 --- a/repository.c +++ b/repository.c @@ -17,6 +17,7 @@ static struct repository the_repo; struct repository *the_repository; struct index_state the_index; +char *the_cwd; void initialize_the_repository(void) { diff --git a/repository.h b/repository.h index a057653981c..45de85d18ef 100644 --- a/repository.h +++ b/repository.h @@ -147,6 +147,7 @@ struct repository { }; extern struct repository *the_repository; +extern char *the_cwd; /* * Define a custom repository layout. Any field can be NULL, which diff --git a/setup.c b/setup.c index 347d7181ae9..4466fa55af3 100644 --- a/setup.c +++ b/setup.c @@ -887,6 +887,7 @@ static const char *setup_explicit_git_dir(const char *gitdirenv, set_git_dir(gitdirenv, 1); if (chdir(worktree)) die_errno(_("cannot chdir to '%s'"), worktree); + the_cwd = xstrdup(cwd->buf + offset); strbuf_addch(cwd, '/'); free(gitfile); return cwd->buf + offset; @@ -940,6 +941,7 @@ static const char *setup_discovered_git_dir(const char *gitdir, /* Make "offset" point past the '/' (already the case for root dirs) */ if (offset != offset_1st_component(cwd->buf)) offset++; + the_cwd = xstrdup(cwd->buf + offset); /* Add a '/' at the end */ strbuf_addch(cwd, '/'); return cwd->buf + offset;