Re: [PATCH 3/4] cache.h: replace 'index_entry_exists()' with 'index_name_pos_sparse()'

"Victoria Dye via GitGitGadget" [off-list ref] writes:

'index_entry_exists()' was original implemented in 20ec2d034c (reset: make
sparse-aware (except --mixed), 2021-11-29) to allow callers to search for an
index entry without expanding a sparse index. That particular case only
required knowing whether the requested entry existed. This patch expands the
amount of information returned by indicating both 1) whether the entry
exists, and 2) its position (or potential position) in the index.

This patch probably should keep index_entry_exists() to potential
new callers that may be introduced by contemporary topics in flight,
by doing something like the following squashed in.  We know that
Shaoxuan's series does add a new callsite, which is of a lessor
concern as that series may want to be rebased on top of these fixes
anyway.  But there may be other topics that may want to add new
calls for this helper that is more trivially and obviously correct
than these four patches, in which case such topics want to proceed
independent of these four patches.

 cache.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git c/cache.h w/cache.h
index ba85435fee..039a32a317 100644
--- c/cache.h
+++ w/cache.h

@@ -839,6 +839,17 @@ int index_name_pos(struct index_state *, const char *name, int namelen);
  */
 int index_name_pos_sparse(struct index_state *, const char *name, int namelen);
 
+/*
+ * This helper function is only kept to help possible
+ * contemporary topics in flight.  Do not use it in new
+ * code; use index_name_pos_sparse() instead.
+ */
+static inline int index_entry_exists(struct index_state *istate,
+				     const char *name, int namelen)
+{
+	return 0 <= index_name_pos_sparse(istate, name, namelen);
+}
+
 /*
  * Some functions return the negative complement of an insert position when a
  * precise match was not found but a position was found where the entry would