thodg/libgit2

diff --git a/include/git2/sys/filter.h b/include/git2/sys/filter.h
index 9a6720a..aa89c7b 100644
--- a/include/git2/sys/filter.h
+++ b/include/git2/sys/filter.h
@@ -29,10 +29,24 @@ GIT_EXTERN(git_filter *) git_filter_lookup(const char *name);
 #define GIT_FILTER_CRLF  "crlf"
 #define GIT_FILTER_IDENT "ident"
 
+/**
+ * This is priority that the internal CRLF filter will be registered with
+ */
 #define GIT_FILTER_CRLF_PRIORITY 0
+
+/**
+ * This is priority that the internal ident filter will be registered with
+ */
 #define GIT_FILTER_IDENT_PRIORITY 100
 
 /**
+ * This is priority to use with a custom filter to imitate a core Git
+ * filter driver, so that it will be run last on checkout and first on
+ * checkin.  You do not have to use this, but it helps compatibility.
+ */
+#define GIT_FILTER_DRIVER_PRIORITY 200
+
+/**
  * Create a new empty filter list
  *
  * Normally you won't use this because `git_filter_list_load` will create
diff --git a/src/ident.c b/src/ident.c
index 3ea9498..23c407f 100644
--- a/src/ident.c
+++ b/src/ident.c
@@ -8,6 +8,7 @@
 #include "git2/sys/filter.h"
 #include "filter.h"
 #include "buffer.h"
+#include "buf_text.h"
 
 static int ident_find_id(
 	const char **id_start, const char **id_end, const char *start, size_t len)
@@ -24,7 +25,7 @@ static int ident_find_id(
 		len = remaining - 1;
 	}
 
-	if (len < 3)
+	if (!found || len < 3)
 		return GIT_ENOTFOUND;
 	*id_start = found;
 
@@ -99,6 +100,10 @@ static int ident_apply(
 {
 	GIT_UNUSED(self); GIT_UNUSED(payload);
 
+	/* Don't filter binary files */
+	if (git_buf_text_is_binary(from))
+		return GIT_ENOTFOUND;
+
 	if (git_filter_source_mode(src) == GIT_FILTER_SMUDGE)
 		return ident_insert_id(to, from, src);
 	else
diff --git a/tests-clar/checkout/crlf.c b/tests-clar/checkout/crlf.c
index 4953609..9a4cbd3 100644
--- a/tests-clar/checkout/crlf.c
+++ b/tests-clar/checkout/crlf.c
@@ -159,21 +159,30 @@ void test_checkout_crlf__with_ident(void)
 
 	cl_git_mkfile("crlf/lf.ident", ALL_LF_TEXT_RAW "\n$Id: initial content$\n");
 	cl_git_mkfile("crlf/crlf.ident", ALL_CRLF_TEXT_RAW "\r\n$Id$\r\n\r\n");
+	cl_git_mkfile("crlf/more1.identlf", "$Id$\n" MORE_LF_TEXT_RAW);
+	cl_git_mkfile("crlf/more2.identcrlf", "\r\n$Id: $\r\n" MORE_CRLF_TEXT_RAW);
 
 	cl_git_pass(git_repository_index(&index, g_repo));
 	cl_git_pass(git_index_add_bypath(index, "lf.ident"));
 	cl_git_pass(git_index_add_bypath(index, "crlf.ident"));
+	cl_git_pass(git_index_add_bypath(index, "more1.identlf"));
+	cl_git_pass(git_index_add_bypath(index, "more2.identcrlf"));
 	cl_repo_commit_from_index(NULL, g_repo, NULL, 0, "Some ident files\n");
 
 	git_checkout_head(g_repo, &opts);
 
-	/* check that blob has $Id$ */
+	/* check that blobs have $Id$ */
 
 	cl_git_pass(git_blob_lookup(&blob, g_repo,
 		& git_index_get_bypath(index, "lf.ident", 0)->oid));
 	cl_assert_equal_s(
 		ALL_LF_TEXT_RAW "\n$Id$\n", git_blob_rawcontent(blob));
+	git_blob_free(blob);
 
+	cl_git_pass(git_blob_lookup(&blob, g_repo,
+		& git_index_get_bypath(index, "more2.identcrlf", 0)->oid));
+	cl_assert_equal_s(
+		"\n$Id$\n" MORE_CRLF_TEXT_AS_LF, git_blob_rawcontent(blob));
 	git_blob_free(blob);
 
 	/* check that filesystem is initially untouched - matching core Git */
@@ -184,20 +193,39 @@ void test_checkout_crlf__with_ident(void)
 	/* check that forced checkout rewrites correctly */
 
 	p_unlink("crlf/lf.ident");
-	p_unlink("crlf/crlflf.ident");
+	p_unlink("crlf/crlf.ident");
+	p_unlink("crlf/more1.identlf");
+	p_unlink("crlf/more2.identcrlf");
 
 	git_checkout_head(g_repo, &opts);
 
-	if (GIT_EOL_NATIVE == GIT_EOL_LF)
+	if (GIT_EOL_NATIVE == GIT_EOL_LF) {
 		cl_assert_equal_file(
 			ALL_LF_TEXT_RAW
 			"\n$Id: fcf6d4d9c212dc66563b1171b1cd99953c756467$\n",
 			0, "crlf/lf.ident");
-	else
+		cl_assert_equal_file(
+			ALL_CRLF_TEXT_AS_LF
+			"\n$Id: f2c66ad9b2b5a734d9bf00d5000cc10a62b8a857$\n\n",
+			0, "crlf/crlf.ident");
+	} else {
 		cl_assert_equal_file(
 			ALL_LF_TEXT_AS_CRLF
 			"\r\n$Id: fcf6d4d9c212dc66563b1171b1cd99953c756467$\r\n",
 			0, "crlf/lf.ident");
+		cl_assert_equal_file(
+			ALL_CRLF_TEXT_RAW
+			"\r\n$Id: f2c66ad9b2b5a734d9bf00d5000cc10a62b8a857$\r\n\r\n",
+			0, "crlf/crlf.ident");
+	}
+
+	cl_assert_equal_file(
+		"$Id: f7830382dac1f1583422be5530fdfbd26289431b$\n"
+		MORE_LF_TEXT_AS_LF, 0, "crlf/more1.identlf");
+
+	cl_assert_equal_file(
+		"\r\n$Id: 74677a68413012ce8d7e7cfc3f12603df3a3eac4$\r\n"
+		MORE_CRLF_TEXT_AS_CRLF, 0, "crlf/more2.identcrlf");
 
 	git_index_free(index);
 }
diff --git a/tests-clar/filter/custom.c b/tests-clar/filter/custom.c
index a2752ef..d6ad4b7 100644
--- a/tests-clar/filter/custom.c
+++ b/tests-clar/filter/custom.c
@@ -6,8 +6,9 @@
 #include "git2/sys/filter.h"
 #include "git2/sys/repository.h"
 
-#define BITFLIP_FILTER_PRIORITY 20
-#define REVERSE_FILTER_PRIORITY 25
+/* picked these to be >= GIT_FILTER_DRIVER_PRIORITY */
+#define BITFLIP_FILTER_PRIORITY 200
+#define REVERSE_FILTER_PRIORITY 250
 
 #define VERY_SECURE_ENCRYPTION(b) ((b) ^ 0xff)
 
@@ -255,3 +256,62 @@ void test_filter_custom__can_register_a_custom_filter_in_the_repository(void)
 	cl_assert_equal_sz(0, git_filter_list_length(fl));
 	git_filter_list_free(fl);
 }
+
+void test_filter_custom__order_dependency(void)
+{
+	git_index *index;
+	git_blob *blob;
+	git_buf buf = { 0 };
+
+	/* so if ident and reverse are used together, an interesting thing
+	 * happens - a reversed "$Id$" string is no longer going to trigger
+	 * ident correctly.  When checking out, the filters should be applied
+	 * in order CLRF, then ident, then reverse, so ident expansion should
+	 * work correctly.  On check in, the content should be reversed, then
+	 * ident, then CRLF filtered.  Let's make sure that works...
+	 */
+
+	cl_git_mkfile(
+		"empty_standard_repo/.gitattributes",
+		"hero.*.rev-ident text ident reverse eol=lf\n");
+
+	cl_git_mkfile(
+		"empty_standard_repo/hero.1.rev-ident",
+		"This is a test\n$Id$\nHave fun!\n");
+
+	cl_git_mkfile(
+		"empty_standard_repo/hero.2.rev-ident",
+		"Another test\n$dI$\nCrazy!\n");
+
+	cl_git_pass(git_repository_index(&index, g_repo));
+	cl_git_pass(git_index_add_bypath(index, "hero.1.rev-ident"));
+	cl_git_pass(git_index_add_bypath(index, "hero.2.rev-ident"));
+	cl_repo_commit_from_index(NULL, g_repo, NULL, 0, "Filter chains\n");
+	git_index_free(index);
+
+	cl_git_pass(git_blob_lookup(&blob, g_repo,
+		& git_index_get_bypath(index, "hero.1.rev-ident", 0)->oid));
+	cl_assert_equal_s(
+		"\n!nuf evaH\n$dI$\ntset a si sihT", git_blob_rawcontent(blob));
+	cl_git_pass(git_blob_filtered_content(&buf, blob, "hero.1.rev-ident", 0));
+	/* no expansion because id was reversed at checkin and now at ident
+	 * time, reverse is not applied yet */
+	cl_assert_equal_s(
+		"This is a test\n$Id$\nHave fun!\n", buf.ptr);
+	git_blob_free(blob);
+
+	cl_git_pass(git_blob_lookup(&blob, g_repo,
+		& git_index_get_bypath(index, "hero.2.rev-ident", 0)->oid));
+	cl_assert_equal_s(
+		"\n!yzarC\n$Id$\ntset rehtonA", git_blob_rawcontent(blob));
+	cl_git_pass(git_blob_filtered_content(&buf, blob, "hero.2.rev-ident", 0));
+	/* expansion because reverse was applied at checkin and at ident time,
+	 * reverse is not applied yet */
+	cl_assert_equal_s(
+		"Another test\n$59001fe193103b1016b27027c0c827d036fd0ac8 :dI$\nCrazy!\n", buf.ptr);
+	cl_assert_equal_i(0, git_oid_strcmp(
+		git_blob_id(blob), "8ca0df630d728c0c72072b6101b301391ef10095"));
+	git_blob_free(blob);
+
+	git_buf_free(&buf);
+}