attr: remove an implicit dependency on the_index

Make the attr API take an index_state instead of assuming the_index in
attr code. All call sites are converted blindly to keep the patch
simple and retain current behavior. Individual call sites may receive
further updates to use the right index instead of the_index.

There is one ugly temporary workaround added in attr.c that needs some
more explanation.

Commit c24f3abace (apply: file commited with CRLF should roundtrip
diff and apply - 2017-08-19) forces one convert_to_git() call to NOT
read the index at all. But what do you know, we read it anyway by
falling back to the_index. When "istate" from convert_to_git is now
propagated down to read_attr_from_array() we will hit segfault
somewhere inside read_blob_data_from_index.

The right way of dealing with this is to kill "use_index" variable and
only follow "istate" but at this stage we are not ready for that:
while most git_attr_set_direction() calls just passes the_index to be
assigned to use_index, unpack-trees passes a different one which is
used by entry.c code, which has no way to know what index to use if we
delete use_index. So this has to be done later.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 7 insertions, 3 deletions

diff --git a/attr.h b/attr.h
index 46340010bb..3daca3c0cb 100644
--- a/attr.h
+++ b/attr.h
@@ -1,6 +1,8 @@
 #ifndef ATTR_H
 #define ATTR_H
 
+struct index_state;
+
 /* An attribute is a pointer to this opaque structure */
 struct git_attr;
 
@@ -60,13 +62,15 @@ void attr_check_free(struct attr_check *check);
  */
 const char *git_attr_name(const struct git_attr *);
 
-int git_check_attr(const char *path, struct attr_check *check);
+int git_check_attr(const struct index_state *istate,
+		   const char *path, struct attr_check *check);
 
 /*
  * Retrieve all attributes that apply to the specified path.
  * check holds the attributes and their values.
  */
-void git_all_attrs(const char *path, struct attr_check *check);
+void git_all_attrs(const struct index_state *istate,
+		   const char *path, struct attr_check *check);
 
 enum git_attr_direction {
 	GIT_ATTR_CHECKIN,
@@ -74,7 +78,7 @@ enum git_attr_direction {
 	GIT_ATTR_INDEX
 };
 void git_attr_set_direction(enum git_attr_direction new_direction,
-			    struct index_state *istate);
+			    const struct index_state *istate);
 
 void attr_start(void);