add --no-filters option to git hash-object

The new option allows the contents to be hashed as is, ignoring any input
filter that would have been chosen by the attributes mechanism.

This option is incompatible with --path and --stdin-paths options.

Signed-off-by: Dmitry Potapov <dpotapov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/git-hash-object.txt b/Documentation/git-hash-object.txt
index fececbf..0af40cf 100644
--- a/Documentation/git-hash-object.txt
+++ b/Documentation/git-hash-object.txt
@@ -9,7 +9,7 @@
 SYNOPSIS
 --------
 [verse]
-'git hash-object' [-t <type>] [-w] [--path=<file>] [--stdin] [--] <file>...
+'git hash-object' [-t <type>] [-w] [--path=<file>|--no-filters] [--stdin] [--] <file>...
 'git hash-object' [-t <type>] [-w] --stdin-paths < <list-of-paths>
 
 DESCRIPTION
@@ -47,6 +47,12 @@
 	temporary files located outside of the working directory or files
 	read from stdin.
 
+--no-filters::
+	Hash the contents as is, ignoring any input filter that would
+	have been chosen by the attributes mechanism, including crlf
+	conversion. If the file is read from standard input then this
+	is always implied, unless the --path option is given.
+
 Author
 ------
 Written by Junio C Hamano <gitster@pobox.com>
diff --git a/hash-object.c b/hash-object.c
index ce04d15..a4d127c 100644
--- a/hash-object.c
+++ b/hash-object.c
@@ -52,7 +52,7 @@
 }
 
 static const char * const hash_object_usage[] = {
-	"git hash-object [-t <type>] [-w] [--path=<file>] [--stdin] [--] <file>...",
+	"git hash-object [-t <type>] [-w] [--path=<file>|--no-filters] [--stdin] [--] <file>...",
 	"git hash-object  --stdin-paths < <list-of-paths>",
 	NULL
 };
@@ -61,6 +61,7 @@
 static int write_object;
 static int hashstdin;
 static int stdin_paths;
+static int no_filters;
 static const char *vpath;
 
 static const struct option hash_object_options[] = {
@@ -68,6 +69,7 @@
 	OPT_BOOLEAN('w', NULL, &write_object, "write the object into the object database"),
 	OPT_BOOLEAN( 0 , "stdin", &hashstdin, "read the object from stdin"),
 	OPT_BOOLEAN( 0 , "stdin-paths", &stdin_paths, "read file names from stdin"),
+	OPT_BOOLEAN( 0 , "no-filters", &no_filters, "store file as is without filters"),
 	OPT_STRING( 0 , "path", &vpath, "file", "process file as it were from this path"),
 	OPT_END()
 };
@@ -99,9 +101,15 @@
 			errstr = "Can't specify files with --stdin-paths";
 		else if (vpath)
 			errstr = "Can't use --stdin-paths with --path";
+		else if (no_filters)
+			errstr = "Can't use --stdin-paths with --no-filters";
 	}
-	else if (hashstdin > 1)
-		errstr = "Multiple --stdin arguments are not supported";
+	else {
+		if (hashstdin > 1)
+			errstr = "Multiple --stdin arguments are not supported";
+		if (vpath && no_filters)
+			errstr = "Can't use --path with --no-filters";
+	}
 
 	if (errstr) {
 		error (errstr);
@@ -116,7 +124,8 @@
 
 		if (0 <= prefix_length)
 			arg = prefix_filename(prefix, prefix_length, arg);
-		hash_object(arg, type, write_object, vpath ? vpath : arg);
+		hash_object(arg, type, write_object,
+			    no_filters ? NULL : vpath ? vpath : arg);
 	}
 
 	if (stdin_paths)
diff --git a/t/t1007-hash-object.sh b/t/t1007-hash-object.sh
index f3972a7..fcdd15a 100755
--- a/t/t1007-hash-object.sh
+++ b/t/t1007-hash-object.sh
@@ -65,6 +65,14 @@
 	echo example | test_must_fail git hash-object --stdin-paths --path=foo
 '
 
+test_expect_success "Can't use --stdin-paths with --no-filters" '
+	echo example | test_must_fail git hash-object --stdin-paths --no-filters
+'
+
+test_expect_success "Can't use --path with --no-filters" '
+	test_must_fail git hash-object --no-filters --path=foo
+'
+
 # Behavior
 
 push_repo
@@ -117,6 +125,22 @@
 	git config --unset core.autocrlf
 '
 
+test_expect_success 'check that --no-filters option works' '
+	echo fooQ | tr Q "\\015" >file0 &&
+	cp file0 file1 &&
+	echo "file0 -crlf" >.gitattributes &&
+	echo "file1 crlf" >>.gitattributes &&
+	git config core.autocrlf true &&
+	file0_sha=$(git hash-object file0) &&
+	file1_sha=$(git hash-object file1) &&
+	test "$file0_sha" != "$file1_sha" &&
+	nofilters_file1=$(git hash-object --no-filters file1) &&
+	test "$file0_sha" = "$nofilters_file1" &&
+	nofilters_file1=$(cat file1 | git hash-object --stdin) &&
+	test "$file0_sha" = "$nofilters_file1" &&
+	git config --unset core.autocrlf
+'
+
 pop_repo
 
 for args in "-w --stdin" "--stdin -w"; do