"Derrick Stolee via GitGitGadget" [off-list ref] writes:
From: Derrick Stolee <redacted>
The for_each_string_list_item() macro takes a string_list and
automatically constructs a for loop to iterate over its contents. This
macro will segfault if the list is non-NULL.
We cannot change the macro to be careful around NULL values because
there are many callers that use the address of a local variable, which
will never be NULL and will cause compile errors with -Werror=address.
For now, leave a documentation comment to try to avoid mistakes in the
future where a caller does not check for a NULL list.
Signed-off-by: Derrick Stolee <redacted>
---
string-list.h | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
For exactly the -Werror=address reason, any other way that checks
list for NULL-ness cannot be done here (other than with Peff's
inline helper that returns the first item or NULL), which is a bit
of shame but this is totally outside the topic, and an additional
comment is a good thing to have here.
Thanks. All four patches look reasonable. Will queue (but after I
make sure I can tag and push out -rc2 today).
quoted hunk
diff --git a/string-list.h b/string-list.h
index d5a744e1438..c7b0d5d0008 100644
--- a/string-list.h
+++ b/string-list.h
@@ -141,7 +141,12 @@ void string_list_clear_func(struct string_list *list, string_list_clear_func_t c
int for_each_string_list(struct string_list *list,
string_list_each_func_t func, void *cb_data);
-/** Iterate over each item, as a macro. */
+/**
+ * Iterate over each item, as a macro.
+ *
+ * Be sure that 'list' is non-NULL. The macro cannot perform NULL
+ * checks due to -Werror=address errors.
+ */
#define for_each_string_list_item(item,list) \
for (item = (list)->items; \
item && item < (list)->items + (list)->nr; \