#
#
# add_dir "tests/diff_on_missing_trailing_newline_at_end_of_file"
# 
# add_file "tests/diff_on_missing_trailing_newline_at_end_of_file/__driver__.lua"
#  content [6075a66de87b656791ec862445c54a922a789eaa]
# 
# add_file "tests/diff_on_missing_trailing_newline_at_end_of_file/file1"
#  content [a43dc27b1c92cccc533ceb3a27035128e26e5b07]
# 
# add_file "tests/diff_on_missing_trailing_newline_at_end_of_file/file13.diff"
#  content [d6e7ac58324be3537427f865e5925f187331f5de]
# 
# add_file "tests/diff_on_missing_trailing_newline_at_end_of_file/file14.diff"
#  content [dcdd2294fa92ad013ddc177c12f3a3bed0c2dd38]
# 
# add_file "tests/diff_on_missing_trailing_newline_at_end_of_file/file2"
#  content [4f8091d2fa31b0598dd0ff6dc936f8d0b47b59d1]
# 
# add_file "tests/diff_on_missing_trailing_newline_at_end_of_file/file23.diff"
#  content [86af946a84931611d6625fe4b555ab42b4e8fc0d]
# 
# add_file "tests/diff_on_missing_trailing_newline_at_end_of_file/file24.diff"
#  content [e6c588f9eac350fac803802708a65f2807b68673]
# 
# add_file "tests/diff_on_missing_trailing_newline_at_end_of_file/file3"
#  content [8aa9b19b304a24ebcd71cfc4a27efc95f8ad8e11]
# 
# add_file "tests/diff_on_missing_trailing_newline_at_end_of_file/file4"
#  content [400b49625ecf4bb7d2d7096ba86801bddb05bb9f]
# 
# patch "diff_patch.cc"
#  from [e359a4c03c6ce548d6414dce11160fbcb6fcb831]
#    to [daeb9be7d8c10d33781b54debd541027618dbfce]
# 
# patch "simplestring_xform.cc"
#  from [5f2e4fcd288a2ec1fd59feb97ebc777b56597608]
#    to [dcaa75eb0ed67ddc119ef62f06c21bd7d13bf5cb]
# 
# patch "simplestring_xform.hh"
#  from [0280d49b889bc0b7b2900d5d123cc8ec95a115eb]
#    to [564a305c99ca931c93956ac3ef903683dcb15db7]
# 
# patch "tests/merge_update_part_of_file/after.diff"
#  from [48e13022c089817683c14884566546af358f7ce9]
#    to [a86dd00b0ad3a0822139372cc83d8ddd746572dd]
# 
# patch "tests/merge_update_part_of_file/before.diff"
#  from [6dffe627ffe07df8df1f15670b065f16264cba6a]
#    to [1f6b25391440c416b57b517d8ce552d7b7a52f80]
#
============================================================
--- tests/diff_on_missing_trailing_newline_at_end_of_file/__driver__.lua	6075a66de87b656791ec862445c54a922a789eaa
+++ tests/diff_on_missing_trailing_newline_at_end_of_file/__driver__.lua	6075a66de87b656791ec862445c54a922a789eaa
@@ -0,0 +1,58 @@
+--
+-- Checks that "mtn diff" output produces the correct results
+-- in case of a missing trailing newline at end of file.
+--
+-- This test goes like this:
+-- 1. Commit two files: 
+--    "file1": containing "foo\nbar\nquux\n"
+--    "file2": containing "foo\nbar\nquux"
+-- 2. Override both "file1" and "file2" with:
+--    "file3": containing "foo\nbar\quux\nbaz\n"
+--    "file4": containing "foo\nbar\quux\nbaz"
+-- 3. Produce a "mtn diff" output and compare against:
+--    "file13.diff" 
+--    "file14.diff" 
+--    "file23.diff" 
+--    "file24.diff" 
+--
+
+mtn_setup()
+
+check(get("file1"))
+check(get("file2"))
+check(get("file3"))
+check(get("file4"))
+check(get("file13.diff"))
+check(get("file14.diff"))
+check(get("file23.diff"))
+check(get("file24.diff"))
+
+addfile("file1")
+addfile("file2")
+commit()
+anc = base_revision()
+
+copy("file3", "file1")
+check(mtn("diff", "file1"), 0, true)
+canonicalize("stdout")
+rename("stdout", "file13.mtn-diff")
+check(samefile("file13.mtn-diff", "file13.diff"))
+
+copy("file4", "file1")
+check(mtn("diff", "file1"), 0, true)
+canonicalize("stdout")
+rename("stdout", "file14.mtn-diff")
+check(samefile("file14.mtn-diff", "file14.diff"))
+
+copy("file3", "file2")
+check(mtn("diff", "file2"), 0, true)
+canonicalize("stdout")
+rename("stdout", "file23.mtn-diff")
+check(samefile("file23.mtn-diff", "file23.diff"))
+
+copy("file4", "file2")
+check(mtn("diff", "file2"), 0, true)
+canonicalize("stdout")
+rename("stdout", "file24.mtn-diff")
+check(samefile("file24.mtn-diff", "file24.diff"))
+
============================================================
--- tests/diff_on_missing_trailing_newline_at_end_of_file/file1	a43dc27b1c92cccc533ceb3a27035128e26e5b07
+++ tests/diff_on_missing_trailing_newline_at_end_of_file/file1	a43dc27b1c92cccc533ceb3a27035128e26e5b07
@@ -0,0 +1,3 @@
+foo
+bar
+quux
============================================================
--- tests/diff_on_missing_trailing_newline_at_end_of_file/file13.diff	d6e7ac58324be3537427f865e5925f187331f5de
+++ tests/diff_on_missing_trailing_newline_at_end_of_file/file13.diff	d6e7ac58324be3537427f865e5925f187331f5de
@@ -0,0 +1,15 @@
+#
+# old_revision [40ea110392539e19c2d251569a3610c0051e0c64]
+#
+# patch "file1"
+#  from [a43dc27b1c92cccc533ceb3a27035128e26e5b07]
+#    to [8aa9b19b304a24ebcd71cfc4a27efc95f8ad8e11]
+#
+============================================================
+--- file1	a43dc27b1c92cccc533ceb3a27035128e26e5b07
++++ file1	8aa9b19b304a24ebcd71cfc4a27efc95f8ad8e11
+@@ -1,3 +1,4 @@ quux
+ foo
+ bar
+ quux
++baz
============================================================
--- tests/diff_on_missing_trailing_newline_at_end_of_file/file14.diff	dcdd2294fa92ad013ddc177c12f3a3bed0c2dd38
+++ tests/diff_on_missing_trailing_newline_at_end_of_file/file14.diff	dcdd2294fa92ad013ddc177c12f3a3bed0c2dd38
@@ -0,0 +1,16 @@
+#
+# old_revision [40ea110392539e19c2d251569a3610c0051e0c64]
+#
+# patch "file1"
+#  from [a43dc27b1c92cccc533ceb3a27035128e26e5b07]
+#    to [400b49625ecf4bb7d2d7096ba86801bddb05bb9f]
+#
+============================================================
+--- file1	a43dc27b1c92cccc533ceb3a27035128e26e5b07
++++ file1	400b49625ecf4bb7d2d7096ba86801bddb05bb9f
+@@ -1,3 +1,4 @@ quux
+ foo
+ bar
+ quux
++baz
+\ No newline at end of file
============================================================
--- tests/diff_on_missing_trailing_newline_at_end_of_file/file2	4f8091d2fa31b0598dd0ff6dc936f8d0b47b59d1
+++ tests/diff_on_missing_trailing_newline_at_end_of_file/file2	4f8091d2fa31b0598dd0ff6dc936f8d0b47b59d1
@@ -0,0 +1,3 @@
+foo
+bar
+quux
============================================================
--- tests/diff_on_missing_trailing_newline_at_end_of_file/file23.diff	86af946a84931611d6625fe4b555ab42b4e8fc0d
+++ tests/diff_on_missing_trailing_newline_at_end_of_file/file23.diff	86af946a84931611d6625fe4b555ab42b4e8fc0d
@@ -0,0 +1,17 @@
+#
+# old_revision [40ea110392539e19c2d251569a3610c0051e0c64]
+#
+# patch "file2"
+#  from [4f8091d2fa31b0598dd0ff6dc936f8d0b47b59d1]
+#    to [8aa9b19b304a24ebcd71cfc4a27efc95f8ad8e11]
+#
+============================================================
+--- file2	4f8091d2fa31b0598dd0ff6dc936f8d0b47b59d1
++++ file2	8aa9b19b304a24ebcd71cfc4a27efc95f8ad8e11
+@@ -1,3 +1,4 @@ bar
+ foo
+ bar
+-quux
+\ No newline at end of file
++quux
++baz
============================================================
--- tests/diff_on_missing_trailing_newline_at_end_of_file/file24.diff	e6c588f9eac350fac803802708a65f2807b68673
+++ tests/diff_on_missing_trailing_newline_at_end_of_file/file24.diff	e6c588f9eac350fac803802708a65f2807b68673
@@ -0,0 +1,18 @@
+#
+# old_revision [40ea110392539e19c2d251569a3610c0051e0c64]
+#
+# patch "file2"
+#  from [4f8091d2fa31b0598dd0ff6dc936f8d0b47b59d1]
+#    to [400b49625ecf4bb7d2d7096ba86801bddb05bb9f]
+#
+============================================================
+--- file2	4f8091d2fa31b0598dd0ff6dc936f8d0b47b59d1
++++ file2	400b49625ecf4bb7d2d7096ba86801bddb05bb9f
+@@ -1,3 +1,4 @@ bar
+ foo
+ bar
+-quux
+\ No newline at end of file
++quux
++baz
+\ No newline at end of file
============================================================
--- tests/diff_on_missing_trailing_newline_at_end_of_file/file3	8aa9b19b304a24ebcd71cfc4a27efc95f8ad8e11
+++ tests/diff_on_missing_trailing_newline_at_end_of_file/file3	8aa9b19b304a24ebcd71cfc4a27efc95f8ad8e11
@@ -0,0 +1,4 @@
+foo
+bar
+quux
+baz
============================================================
--- tests/diff_on_missing_trailing_newline_at_end_of_file/file4	400b49625ecf4bb7d2d7096ba86801bddb05bb9f
+++ tests/diff_on_missing_trailing_newline_at_end_of_file/file4	400b49625ecf4bb7d2d7096ba86801bddb05bb9f
@@ -0,0 +1,4 @@
+foo
+bar
+quux
+baz
============================================================
--- diff_patch.cc	e359a4c03c6ce548d6414dce11160fbcb6fcb831
+++ diff_patch.cc	daeb9be7d8c10d33781b54debd541027618dbfce
@@ -1010,17 +1010,17 @@ void walk_hunk_consumer(vector<long, QA(
           while (idx(lines2,b) != *i)
             cons.insert_at(b++);
         }
-      if (b < lines2.size())
+      if (a < lines1.size())
         {
           cons.advance_to(a);
-          while(b < lines2.size())
-            cons.insert_at(b++);
+          while(a < lines1.size())
+            cons.delete_at(a++);
         }
-      if (a < lines1.size())
+      if (b < lines2.size())
         {
           cons.advance_to(a);
-          while(a < lines1.size())
-            cons.delete_at(a++);
+          while(b < lines2.size())
+            cons.insert_at(b++);
         }
       cons.flush_hunk(a);
     }
@@ -1349,8 +1349,8 @@ make_diff(string const & filename1,
     }
 
   vector<string> lines1, lines2;
-  split_into_lines(data1(), lines1);
-  split_into_lines(data2(), lines2);
+  split_into_lines(data1(), lines1, true);
+  split_into_lines(data2(), lines2, true);
 
   vector<long, QA(long)> left_interned;
   vector<long, QA(long)> right_interned;
============================================================
--- simplestring_xform.cc	5f2e4fcd288a2ec1fd59feb97ebc777b56597608
+++ simplestring_xform.cc	dcaa75eb0ed67ddc119ef62f06c21bd7d13bf5cb
@@ -50,9 +50,24 @@ void split_into_lines(string const & in,
 }
 
 void split_into_lines(string const & in,
+                      vector<string> & out,
+                      bool diff_compat)
+{
+  return split_into_lines(in, constants::default_encoding, out, diff_compat);
+}
+
+void split_into_lines(string const & in,
                       string const & encoding,
                       vector<string> & out)
 {
+  return split_into_lines(in, encoding, out, false);
+}
+
+void split_into_lines(string const & in,
+                      string const & encoding,
+                      vector<string> & out,
+                      bool diff_compat)
+{
   string lc_encoding = lowercase(encoding);
   out.clear();
 
@@ -92,8 +107,16 @@ void split_into_lines(string const & in,
             break;
           end = in.find_first_of("\r\n", begin);
         }
-      if (begin < in.size())
-        out.push_back(in.substr(begin, in.size() - begin));
+      if (begin < in.size()) {
+        // special case: last line without trailing newline
+        string s = in.substr(begin, in.size() - begin);
+        if (diff_compat) {
+          // special handling: produce diff(1) compatible output
+          s += (in.find_first_of("\r") != string::npos ? "\r\n" : "\n");
+          s += "\\ No newline at end of file"; 
+        }
+        out.push_back(s);
+      }
     }
   else
     {
============================================================
--- simplestring_xform.hh	0280d49b889bc0b7b2900d5d123cc8ec95a115eb
+++ simplestring_xform.hh	564a305c99ca931c93956ac3ef903683dcb15db7
@@ -13,6 +13,15 @@ void split_into_lines(std::string const 
                       std::string const & encoding,
                       std::vector<std::string> & out);
 
+void split_into_lines(std::string const & in,
+                      std::vector<std::string> & out,
+                      bool diff_compat);
+
+void split_into_lines(std::string const & in,
+                      std::string const & encoding,
+                      std::vector<std::string> & out,
+                      bool diff_compat);
+
 void join_lines(std::vector<std::string> const & in,
                 std::string & out,
                 std::string const & linesep);
============================================================
--- tests/merge_update_part_of_file/after.diff	48e13022c089817683c14884566546af358f7ce9
+++ tests/merge_update_part_of_file/after.diff	a86dd00b0ad3a0822139372cc83d8ddd746572dd
@@ -12,5 +12,5 @@
  two
  chunks
  
+-line to be changed
 +line changed
--line to be changed
============================================================
--- tests/merge_update_part_of_file/before.diff	6dffe627ffe07df8df1f15670b065f16264cba6a
+++ tests/merge_update_part_of_file/before.diff	1f6b25391440c416b57b517d8ce552d7b7a52f80
@@ -23,5 +23,5 @@
  two
  chunks
  
+-line to be changed
 +line changed
--line to be changed