Re: [PATCH 1/2] config: check if config path is a file before parsing it

> If a directory is given as a config file by accident, we keep open it
> as a file. The behavior of fopen() in this case seems to be
> undefined.
> 
> On Linux, we open a directory as a file ok, then get error (which we
> consider eof) on the first read. So the config parser sees this "file"
> as empty (i.e. valid config). All is well and we don't complain
> anything (but we should).
> 
> The situation is slighly different on Windows. I think fopen() returns
> NULL. And we get a very unhelpful message:
> 
>     $ cat >abc <<EOF
>     [include]
>         path = /tmp/foo
>     EOF
>     $ mkdir /tmp/foo
>     $ git config --includes --file=abc core.bare
>     fatal: bad config line 3 in file abc
> 
> Opening a directory is wrong in the first place. Avoid it. If caught,
> print something better. With this patch, we have
> 
>     $ git config --includes --file=abc core.bare
>     error: '/tmp/foo' is not a file
>     fatal: bad config line 3 in file abc
> 
> It's not perfect (line should be 2 instead of 3). But it's definitely
> improving.
> 
> The new test is only relevant on linux where we blindly open the
> directory and consider it an empty file. On Windows, the test should
> pass even without this patch.
> ---
>  abspath.c              | 7 +++++++
>  cache.h                | 1 +
>  config.c               | 9 +++++++++
>  t/t1300-repo-config.sh | 5 +++++
>  4 files changed, 22 insertions(+)
> 
> diff --git a/abspath.c b/abspath.c
> index 2f0c26e0e2..373cc3abb2 100644
> --- a/abspath.c
> +++ b/abspath.c
> @@ -11,6 +11,13 @@ int is_directory(const char *path)
>  	return (!stat(path, &st) && S_ISDIR(st.st_mode));
>  }
>  
> +int is_not_file(const char *path)
> +{
> +	struct stat st;
> +
> +	return !stat(path, &st) && !S_ISREG(st.st_mode);
> +}
> +
>  /* removes the last path component from 'path' except if 'path' is root */
>  static void strip_last_component(struct strbuf *path)
>  {
> diff --git a/cache.h b/cache.h
> index 80b6372cf7..bdd1402ab9 100644
> --- a/cache.h
> +++ b/cache.h
> @@ -1149,6 +1149,7 @@ static inline int is_absolute_path(const char *path)
>  	return is_dir_sep(path[0]) || has_dos_drive_prefix(path);
>  }
>  int is_directory(const char *);
> +int is_not_file(const char *);
>  char *strbuf_realpath(struct strbuf *resolved, const char *path,
>  		      int die_on_error);
>  const char *real_path(const char *path);
> diff --git a/config.c b/config.c
> index c6b874a7bf..c21c0ce433 100644
> --- a/config.c
> +++ b/config.c
> @@ -13,6 +13,7 @@
>  #include "hashmap.h"
>  #include "string-list.h"
>  #include "utf8.h"
> +#include "dir.h"