On 03/08, René Scharfe wrote:
> Am 08.03.2017 um 16:43 schrieb Johannes Schindelin:
> > In 4ac9006f832 (real_path: have callers use real_pathdup and
> > strbuf_realpath, 2016-12-12), we changed the xstrdup(real_path())
> > pattern to use real_pathdup() directly.
> >
> > The only problem with this change is that real_path() calls
> > strbuf_realpath() with die_on_error = 1 while real_pathdup() calls it
> > with die_on_error = 0. Meaning that in cases where real_path() causes
> > Git to die() with an error message, real_pathdup() is silent and returns
> > NULL instead.
> >
> > The callers, however, are ill-prepared for that change, as they expect
> > the return value to be non-NULL.
> >
> > This patch fixes that by extending real_pathdup()'s signature to accept
> > the die_on_error flag and simply pass it through to strbuf_realpath(),
> > and then adjust all callers after a careful audit whether they would
> > handle NULLs well.
> >
> > Note: this fix not only prevents NULL pointer accesses, but it also
> > reintroduces the error messages that were lost with the change to
> > real_pathdup().
> >
> > Signed-off-by: Johannes Schindelin <[email protected]>
> > ---
> > abspath.c | 4 ++--
> > builtin/init-db.c | 6 +++---
> > cache.h | 2 +-
> > dir.c | 4 ++--
> > environment.c | 2 +-
> > setup.c | 4 ++--
> > submodule.c | 10 +++++-----
> > t/t1501-work-tree.sh | 2 +-
> > worktree.c | 2 +-
> > 9 files changed, 18 insertions(+), 18 deletions(-)
> >
> > diff --git a/abspath.c b/abspath.c
> > index 2f0c26e0e2c..b02e068aa34 100644
> > --- a/abspath.c
> > +++ b/abspath.c
> > @@ -214,12 +214,12 @@ const char *real_path_if_valid(const char *path)
> > return strbuf_realpath(&realpath, path, 0);
> > }
> >
> > -char *real_pathdup(const char *path)
> > +char *real_pathdup(const char *path, int die_on_error)
>
> Adding a gentle variant (with the current implementation) and making
> real_pathdup() die on error would be nicer, as it doesn't require
> callers to pass magic flag values. Most cases use the dying variant,
> so such a patch would have to touch less places:
I agree with Junio and Rene that a gentle version would make the api
slightly nicer (and more consistant with some of the other api's we have
in git).
This is exactly what I should have done back when I originally made the
change. Sorry for missing this!
> ---
> abspath.c | 7 +++++++
> cache.h | 1 +
> setup.c | 2 +-
> t/t1501-work-tree.sh | 2 +-
> 4 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/abspath.c b/abspath.c
> index 2f0c26e0e2..f3fcff8b1b 100644
> --- a/abspath.c
> +++ b/abspath.c
> @@ -217,6 +217,13 @@ const char *real_path_if_valid(const char *path)
> char *real_pathdup(const char *path)
> {
> struct strbuf realpath = STRBUF_INIT;
> + strbuf_realpath(&realpath, path, 1);
> + return strbuf_detach(&realpath, NULL);
> +}
> +
> +char *real_pathdup_gently(const char *path)
> +{
> + struct strbuf realpath = STRBUF_INIT;
> char *retval = NULL;
>
> if (strbuf_realpath(&realpath, path, 0))
> diff --git a/cache.h b/cache.h
> index 80b6372cf7..9dfbce702e 100644
> --- a/cache.h
> +++ b/cache.h
> @@ -1154,6 +1154,7 @@ char *strbuf_realpath(struct strbuf *resolved, const
> char *path,
> const char *real_path(const char *path);
> const char *real_path_if_valid(const char *path);
> char *real_pathdup(const char *path);
> +char *real_pathdup_gently(const char *path);
> const char *absolute_path(const char *path);
> char *absolute_pathdup(const char *path);
> const char *remove_leading_path(const char *in, const char *prefix);
> diff --git a/setup.c b/setup.c
> index f14cbcd338..398ea8a913 100644
> --- a/setup.c
> +++ b/setup.c
> @@ -806,7 +806,7 @@ static int canonicalize_ceiling_entry(struct
> string_list_item *item,
> /* Keep entry but do not canonicalize it */
> return 1;
> } else {
> - char *real_path = real_pathdup(ceil);
> + char *real_path = real_pathdup_gently(ceil);
> if (!real_path) {
> return 0;
> }
> diff --git a/t/t1501-work-tree.sh b/t/t1501-work-tree.sh
> index 046d9b7909..b06210ec5e 100755
> --- a/t/t1501-work-tree.sh
> +++ b/t/t1501-work-tree.sh
> @@ -423,7 +423,7 @@ test_expect_success '$GIT_WORK_TREE overrides
> $GIT_DIR/common' '
> )
> '
>
> -test_expect_failure 'error out gracefully on invalid $GIT_WORK_TREE' '
> +test_expect_success 'error out gracefully on invalid $GIT_WORK_TREE' '
> (
> GIT_WORK_TREE=/.invalid/work/tree &&
> export GIT_WORK_TREE &&
> --
> 2.12.0
>
--
Brandon Williams
