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 <johannes.schindelin@xxxxxx>
> ---
> 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:
---
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