# [PATCH] tree-walk.c: fix some sparse 'NULL pointer' warnings 2 messages from 2015-05-19 to 2015-05-20. Participants: Ramsay Jones, David Turner. Thread: https://gitlist.dev/t/39377 ## Ramsay Jones, 2015-05-19 22:16 Subject: [PATCH] tree-walk.c: fix some sparse 'NULL pointer' warnings Message-ID: <555BB633.8030204@ramsay1.demon.co.uk> URL: https://gitlist.dev/e/555BB633.8030204%40ramsay1.demon.co.uk ``` Commit 811cd77b ("tree-walk: learn get_tree_entry_follow_symlinks", 14-05-2015) introduced a new function to locate an object by path while following symlinks in the repository. However, sparse now issues some "Using plain integer as NULL pointer" warnings as follows: SP tree-walk.c tree-walk.c:517:31: warning: Using plain integer as NULL pointer tree-walk.c:521:28: warning: Using plain integer as NULL pointer The first warning relates to the use of an '{0}' initializer for the 'struct tree_desc' t. The first field of this structure has pointer type. A simple solution would replace the initializer expression with '{NULL}'. However, we choose to remove the initializer expression and make the initialization more explicit with a call to the 'init_tree_desc' function. The second warning relates to the '0' initializer for the buf field of the 'result_path' strbuf pointer. A simple solution would replace this initializer with 'NULL'. However, this would violate a strbuf invariant that the 'buf' field is never NULL. (see strbuf documentation in strbuf.h header.) Assuming the documentation of 'get_tree_entry_follow_symlinks' regarding the 'result_path' parameter is observed by callers (ie that the parameter points to an _unitialized_ strbuf), a better solution is to simply call the 'strbuf_init' function. Signed-off-by: Ramsay Jones --- Hi David, If you need to re-roll the patches in your 'dt/cat-file-follow-symlinks' branch, could you please squash this, or something like this, into the relevant patch (commit 811cd77b). Thanks! ATB, Ramsay Jones tree-walk.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/tree-walk.c b/tree-walk.c index 8031f3a..6dccd2d 100644 --- a/tree-walk.c +++ b/tree-walk.c @@ -514,13 +514,12 @@ enum follow_symlinks_result get_tree_entry_follow_symlinks(unsigned char *tree_s ssize_t parents_nr = 0; unsigned char current_tree_sha1[20]; struct strbuf namebuf = STRBUF_INIT; - struct tree_desc t = {0}; + struct tree_desc t; int follows_remaining = GET_TREE_ENTRY_FOLLOW_SYMLINKS_MAX_LINKS; int i; - result_path->buf = 0; - result_path->alloc = 0; - result_path->len = 0; + init_tree_desc(&t, NULL, 0UL); + strbuf_init(result_path, 0); strbuf_addstr(&namebuf, name); hashcpy(current_tree_sha1, tree_sha1); -- 2.4.0 ``` ## David Turner, 2015-05-20 17:04 Subject: Re: [PATCH] tree-walk.c: fix some sparse 'NULL pointer' warnings Message-ID: <1432141461.15896.6.camel@ubuntu> URL: https://gitlist.dev/e/1432141461.15896.6.camel%40ubuntu In-Reply-To: <555BB633.8030204@ramsay1.demon.co.uk> ``` re-rolled, thanks. On Tue, 2015-05-19 at 23:16 +0100, Ramsay Jones wrote: > Commit 811cd77b ("tree-walk: learn get_tree_entry_follow_symlinks", > 14-05-2015) introduced a new function to locate an object by path > while following symlinks in the repository. However, sparse now > issues some "Using plain integer as NULL pointer" warnings as > follows: > > SP tree-walk.c > tree-walk.c:517:31: warning: Using plain integer as NULL pointer > tree-walk.c:521:28: warning: Using plain integer as NULL pointer > > The first warning relates to the use of an '{0}' initializer for > the 'struct tree_desc' t. The first field of this structure has > pointer type. A simple solution would replace the initializer > expression with '{NULL}'. However, we choose to remove the > initializer expression and make the initialization more explicit > with a call to the 'init_tree_desc' function. > > The second warning relates to the '0' initializer for the buf > field of the 'result_path' strbuf pointer. A simple solution > would replace this initializer with 'NULL'. However, this would > violate a strbuf invariant that the 'buf' field is never NULL. > (see strbuf documentation in strbuf.h header.) Assuming the > documentation of 'get_tree_entry_follow_symlinks' regarding the > 'result_path' parameter is observed by callers (ie that the > parameter points to an _unitialized_ strbuf), a better solution > is to simply call the 'strbuf_init' function. > > Signed-off-by: Ramsay Jones > --- > > Hi David, > > If you need to re-roll the patches in your 'dt/cat-file-follow-symlinks' > branch, could you please squash this, or something like this, into the > relevant patch (commit 811cd77b). > > Thanks! > > ATB, > Ramsay Jones > > tree-walk.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/tree-walk.c b/tree-walk.c > index 8031f3a..6dccd2d 100644 > --- a/tree-walk.c > +++ b/tree-walk.c > @@ -514,13 +514,12 @@ enum follow_symlinks_result get_tree_entry_follow_symlinks(unsigned char *tree_s > ssize_t parents_nr = 0; > unsigned char current_tree_sha1[20]; > struct strbuf namebuf = STRBUF_INIT; > - struct tree_desc t = {0}; > + struct tree_desc t; > int follows_remaining = GET_TREE_ENTRY_FOLLOW_SYMLINKS_MAX_LINKS; > int i; > > - result_path->buf = 0; > - result_path->alloc = 0; > - result_path->len = 0; > + init_tree_desc(&t, NULL, 0UL); > + strbuf_init(result_path, 0); > strbuf_addstr(&namebuf, name); > hashcpy(current_tree_sha1, tree_sha1); > ```