[PATCH 03/21] refactor find_ref_by_name() to accept const list
From: Jay Soffian <hidden>
Date: 2016-06-15 22:46:17
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Jeff King <redacted> Since it doesn't actually touch its argument, this makes sense. However, we still want to return a non-const version (which requires a cast) so that this: struct ref *a, *b; a = find_ref_by_name(b); works. Unfortunately, you can also silently strip the const from a variable: struct ref *a; const struct ref *b; a = find_ref_by_name(b); This is a classic C const problem because there is no way to say "return the type with the same constness that was passed to us"; we provide the same semantics as standard library functions like strchr. Signed-off-by: Jeff King <redacted> Signed-off-by: Jay Soffian <redacted> --- cache.h | 2 +- refs.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-)
diff --git a/cache.h b/cache.h
index 189151d..609380d 100644
--- a/cache.h
+++ b/cache.h@@ -801,7 +801,7 @@ struct ref { #define REF_HEADS (1u << 1) #define REF_TAGS (1u << 2) -extern struct ref *find_ref_by_name(struct ref *list, const char *name); +extern struct ref *find_ref_by_name(const struct ref *list, const char *name); #define CONNECT_VERBOSE (1u << 0) extern struct child_process *git_connect(int fd[2], const char *url, const char *prog, int flags);
diff --git a/refs.c b/refs.c
index 6eb5f53..b2a37e1 100644
--- a/refs.c
+++ b/refs.c@@ -1628,10 +1628,10 @@ int update_ref(const char *action, const char *refname, return 0; } -struct ref *find_ref_by_name(struct ref *list, const char *name) +struct ref *find_ref_by_name(const struct ref *list, const char *name) { for ( ; list; list = list->next) if (!strcmp(list->name, name)) - return list; + return (struct ref *)list; return NULL; }
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1.6.2.rc1.291.g83eb