Merge pull request #4267 from mohseenrm/master

adding GIT_FILTER_VERSION to GIT_FILTER_INIT as part of convention
diff --git a/include/git2/sys/filter.h b/include/git2/sys/filter.h
index d0e5d4d..6d575d4 100644
--- a/include/git2/sys/filter.h
+++ b/include/git2/sys/filter.h
@@ -271,6 +271,17 @@
 };
 
 #define GIT_FILTER_VERSION 1
+#define GIT_FILTER_INIT {GIT_FILTER_VERSION}
+
+/**
+ * Initializes a `git_filter` with default values. Equivalent to
+ * creating an instance with GIT_FILTER_INIT.
+ *
+ * @param filter the `git_filter` struct to initialize.
+ * @param version Version the struct; pass `GIT_FILTER_VERSION`
+ * @return Zero on success; -1 on failure.
+ */
+GIT_EXTERN(int) git_filter_init(git_filter *filter, unsigned int version);
 
 /**
  * Register a filter under a given name with a given priority.
diff --git a/src/filter.c b/src/filter.c
index e74cc10..361e085 100644
--- a/src/filter.c
+++ b/src/filter.c
@@ -895,7 +895,7 @@
 			git_array_size(filters->filters) - 1 - i : i;
 		git_filter_entry *fe = git_array_get(filters->filters, filter_idx);
 		git_writestream *filter_stream;
-		
+
 		assert(fe->filter->stream || fe->filter->apply);
 
 		/* If necessary, create a stream that proxies the traditional
@@ -1022,3 +1022,9 @@
 
 	return git_filter_list_stream_data(filters, &in, target);
 }
+
+int git_filter_init(git_filter *filter, unsigned int version)
+{
+	GIT_INIT_STRUCTURE_FROM_TEMPLATE(filter, version, git_filter, GIT_FILTER_INIT);
+	return 0;
+}
diff --git a/tests/core/structinit.c b/tests/core/structinit.c
index 2d21440..78503fc 100644
--- a/tests/core/structinit.c
+++ b/tests/core/structinit.c
@@ -1,5 +1,6 @@
 #include "clar_libgit2.h"
 #include <git2/sys/config.h>
+#include <git2/sys/filter.h>
 #include <git2/sys/odb_backend.h>
 #include <git2/sys/refdb_backend.h>
 #include <git2/sys/transport.h>
@@ -96,6 +97,11 @@
 		git_diff_find_options, GIT_DIFF_FIND_OPTIONS_VERSION, \
 		GIT_DIFF_FIND_OPTIONS_INIT, git_diff_find_init_options);
 
+	/* filter */
+	CHECK_MACRO_FUNC_INIT_EQUAL( \
+		git_filter, GIT_FILTER_VERSION, \
+		GIT_FILTER_INIT, git_filter_init);
+
 	/* merge_file_input */
 	CHECK_MACRO_FUNC_INIT_EQUAL( \
 		git_merge_file_input, GIT_MERGE_FILE_INPUT_VERSION, \