Detect file creation/deletion when parsing patch files created with d…

…iff -N

src/fname.mll

@@ -53,12 +53,17 @@ and lex_filename buf = parse
 
 {
 let parse s =
-  let filename, _date =
+  let filename, date =
     match String.cut '\t' s with
     | None -> (s, "")
     | Some x -> x
   in
-  if filename = "/dev/null" then
+  if filename = "/dev/null" ||
+     String.is_prefix ~prefix:"1970-" date ||
+     String.is_prefix ~prefix:"1969-" date ||
+     String.is_suffix ~suffix:" 1970" date ||
+     String.is_suffix ~suffix:" 1969" date then
+    (* See https://github.com/hannesm/patch/issues/8 *)
     Ok None
   else
     let lexbuf = Lexing.from_string filename in

test/test.ml

@@ -899,7 +899,7 @@ diff -ruaN a/test b/test
 |}
 
 let macos_diff_N_deletion =
-  operations [Patch.Edit ("a/test", "b/test")] macos_diff_N_deletion
+  operations [Patch.Delete "a/test"] macos_diff_N_deletion
 
 let openbsd_diff_N_deletion = {|\
 diff -ruaN a/test b/test
@@ -910,7 +910,7 @@ diff -ruaN a/test b/test
 |}
 
 let openbsd_diff_N_deletion =
-  operations [Patch.Edit ("a/test", "b/test")] openbsd_diff_N_deletion
+  operations [Patch.Delete "a/test"] openbsd_diff_N_deletion
 
 let gnu_diff_N_deletion = {|\
 diff -ruaN a/test b/test
@@ -921,7 +921,7 @@ diff -ruaN a/test b/test
 |}
 
 let gnu_diff_N_deletion =
-  operations [Patch.Edit ("a/test", "b/test")] gnu_diff_N_deletion
+  operations [Patch.Delete "a/test"] gnu_diff_N_deletion
 
 let busybox_diff_N_deletion = {|\
 --- a/test