Re: [PATCH v2] setup: don't die if realpath(3) fails on getcwd(3)

> On 5/21/22 9:53 AM, Kevin Locke wrote:
> > +		free((char*)tmp_original_cwd);
> 
> Hm. I'm never a fan of this casting, but it existed before. It's
> because tmp_original_cwd is exposed globally in cache.h, which
> is _really widely_. However, there are only two uses: setup.c,
> which defines it, and common-main.c, which initializes it during
> process startup.
> 
> The following diff could apply before your commit, removing this
> use of "const char *", but maybe it doesn't fit normal Git
> coding guidelines (putting the extern directly in a *.c file):
> 
> --- >8 ---
> 
> diff --git a/cache.h b/cache.h
> index aaf334e2aa4..ce9cd6fa3f0 100644
> --- a/cache.h
> +++ b/cache.h
> @@ -1797,7 +1797,6 @@ struct startup_info {
>  	const char *original_cwd;
>  };
>  extern struct startup_info *startup_info;
> -extern const char *tmp_original_cwd;
>  
>  /* merge.c */
>  struct commit_list;
> diff --git a/common-main.c b/common-main.c
> index 29fb7452f8a..e472258b83b 100644
> --- a/common-main.c
> +++ b/common-main.c
> @@ -23,6 +23,8 @@ static void restore_sigpipe_to_default(void)
>  	signal(SIGPIPE, SIG_DFL);
>  }
>  
> +extern char *tmp_original_cwd;
> +
>  int main(int argc, const char **argv)
>  {
>  	int result;
> diff --git a/setup.c b/setup.c
> index 04ce33cdcd4..86986317490 100644
> --- a/setup.c
> +++ b/setup.c
> @@ -12,7 +12,7 @@ static int work_tree_config_is_bogus;
>  
>  static struct startup_info the_startup_info;
>  struct startup_info *startup_info = &the_startup_info;
> -const char *tmp_original_cwd;
> +char *tmp_original_cwd;
>  
>  /*
>   * The input parameter must contain an absolute path, and it must already be
> @@ -459,7 +459,7 @@ static void setup_original_cwd(void)
>  
>  	/* Normalize the directory */
>  	strbuf_realpath(&tmp, tmp_original_cwd, 1);
> -	free((char*)tmp_original_cwd);
> +	free(tmp_original_cwd);
>  	tmp_original_cwd = NULL;
>  	startup_info->original_cwd = strbuf_detach(&tmp, NULL);
>  
> --- >8 ---

>> +		tmp_original_cwd = NULL;
>> +		startup_info->original_cwd = strbuf_detach(&tmp, NULL);
>> +	} else {
>> +		trace_printf("realpath(cwd) failed: %s\n", strerror(errno));
> 
> It could also be helpful to include a trace2 output, since
> most modern tracing uses that mechanism:
> 
> 		trace2_data_string("setup", the_repository,
> 				   "realpath-path", tmp_original_cwd);
> 		trace2_data_string("setup", the_repository,
> 				   "realpath-failure", strerror(errno));
> 
> But this is also unlikely to be necessary. We can instruct
> a user to rerun their command with GIT_TRACE=1 if we see
> this error in the wild.