[PATCH 04/12] alter: use space_index instead of index_find where appropriate

[Vladimir Davydov <vdavydov.dev@gmail.com>]

Using index_find_xc() in AlterSpaceOp::commit and rollback is confusing,
because these functions may not throw. Let's use space_index instead as
we are sure that the index we are looking for must exist. While we are
at it, add some missing assertions.
---
 src/box/alter.cc | 24 ++++++++++++++++--------
 1 file changed, 16 insertions(+), 8 deletions(-)

diff --git a/src/box/alter.cc b/src/box/alter.cc
index ec7af24b..36310f1c 100644
--- a/src/box/alter.cc
+++ b/src/box/alter.cc
@@ -1006,8 +1006,9 @@ DropIndex::alter(struct alter_space *alter)
 void
 DropIndex::commit(struct alter_space *alter, int64_t /* signature */)
 {
-	struct index *index = index_find_xc(alter->old_space,
-					    old_index_def->iid);
+	struct index *index = space_index(alter->old_space,
+					  old_index_def->iid);
+	assert(index != NULL);
 	index_commit_drop(index);
 }
 
@@ -1105,6 +1106,7 @@ ModifyIndex::commit(struct alter_space *alter, int64_t signature)
 {
 	struct index *new_index = space_index(alter->new_space,
 					      new_index_def->iid);
+	assert(new_index != NULL);
 	index_commit_modify(new_index, signature);
 }
 
@@ -1186,8 +1188,9 @@ CreateIndex::alter(struct alter_space *alter)
 	/**
 	 * Get the new index and build it.
 	 */
-	struct index *new_index = index_find_xc(alter->new_space,
-						new_index_def->iid);
+	struct index *new_index = space_index(alter->new_space,
+					      new_index_def->iid);
+	assert(new_index != NULL);
 	space_build_secondary_key_xc(alter->new_space,
 				     alter->new_space, new_index);
 }
@@ -1195,16 +1198,18 @@ CreateIndex::alter(struct alter_space *alter)
 void
 CreateIndex::commit(struct alter_space *alter, int64_t signature)
 {
-	struct index *new_index = index_find_xc(alter->new_space,
-						new_index_def->iid);
+	struct index *new_index = space_index(alter->new_space,
+					      new_index_def->iid);
+	assert(new_index != NULL);
 	index_commit_create(new_index, signature);
 }
 
 void
 CreateIndex::rollback(struct alter_space *alter)
 {
-	struct index *new_index = index_find_xc(alter->new_space,
-						new_index_def->iid);
+	struct index *new_index = space_index(alter->new_space,
+					      new_index_def->iid);
+	assert(new_index != NULL);
 	index_abort_create(new_index);
 }
 
@@ -1269,8 +1274,10 @@ RebuildIndex::commit(struct alter_space *alter, int64_t signature)
 {
 	struct index *old_index = space_index(alter->old_space,
 					      old_index_def->iid);
+	assert(old_index != NULL);
 	struct index *new_index = space_index(alter->new_space,
 					      new_index_def->iid);
+	assert(new_index != NULL);
 	index_commit_drop(old_index);
 	index_commit_create(new_index, signature);
 }
@@ -1280,6 +1287,7 @@ RebuildIndex::rollback(struct alter_space *alter)
 {
 	struct index *new_index = space_index(alter->new_space,
 					      new_index_def->iid);
+	assert(new_index != NULL);
 	index_abort_create(new_index);
 }
 
-- 
2.11.0