vim-patch:9.1.0743: diff mode does not handle overlapping diffs correctly (#30532)

Problem:  diff mode does not handle overlapping diffs correctly
Solution: correct the logic to handle overlapping blocks
          (Yukihiro Nakadaira)

Vim merges overlapped diff blocks and it doesn't work expectedly
in some situation.

closes: vim/vim#15735

https://github.com/vim/vim/commit/06fe70c183a53ea97cd42ace490d4fb9fd14f042

Co-authored-by: Yukihiro Nakadaira <yukihiro.nakadaira@gmail.com>

1 files changed, 208 insertions, 0 deletions

diff --git a/test/old/testdir/test_diffmode.vim b/test/old/testdir/test_diffmode.vim
index 84cb7eb376..a448ed9b7f 100644
--- a/test/old/testdir/test_diffmode.vim
+++ b/test/old/testdir/test_diffmode.vim
@@ -830,6 +830,15 @@ func WriteDiffFiles(buf, list1, list2)
   endif
 endfunc
 
+func WriteDiffFiles3(buf, list1, list2, list3)
+  call writefile(a:list1, 'Xdifile1')
+  call writefile(a:list2, 'Xdifile2')
+  call writefile(a:list3, 'Xdifile3')
+  if a:buf
+    call term_sendkeys(a:buf, ":checktime\<CR>")
+  endif
+endfunc
+
 " Verify a screendump with both the internal and external diff.
 func VerifyBoth(buf, dumpfile, extra)
   " trailing : for leaving the cursor on the command line
@@ -1799,4 +1808,203 @@ func Test_diff_eob_halfpage()
   %bwipe!
 endfunc
 
+func Test_diff_overlapped_diff_blocks_will_be_merged()
+  CheckScreendump
+
+  let lines =<< trim END
+    func DiffExprStub()
+      let txt_in = readfile(v:fname_in)
+      let txt_new = readfile(v:fname_new)
+      if txt_in == ["line1"] && txt_new == ["line2"]
+        call writefile(["1c1"], v:fname_out)
+      elseif txt_in == readfile("Xdiin1") && txt_new == readfile("Xdinew1")
+        call writefile(readfile("Xdiout1"), v:fname_out)
+      elseif txt_in == readfile("Xdiin2") && txt_new == readfile("Xdinew2")
+        call writefile(readfile("Xdiout2"), v:fname_out)
+      endif
+    endfunc
+  END
+  call writefile(lines, 'XdiffSetup', 'D')
+
+  call WriteDiffFiles(0, [], [])
+  let buf = RunVimInTerminal('-d -S XdiffSetup Xdifile1 Xdifile2', {})
+  call term_sendkeys(buf, ":set autoread\<CR>\<c-w>w:set autoread\<CR>\<c-w>w")
+
+  call WriteDiffFiles(buf, ["a", "b"], ["x", "x"])
+  call writefile(["a", "b"], "Xdiin1")
+  call writefile(["x", "x"], "Xdinew1")
+  call writefile(["1c1", "2c2"], "Xdiout1")
+  call term_sendkeys(buf, ":set diffexpr=DiffExprStub()\<CR>:")
+  call VerifyBoth(buf, "Test_diff_overlapped_2.01", "")
+  call term_sendkeys(buf, ":set diffexpr&\<CR>:")
+
+  call WriteDiffFiles(buf, ["a", "b", "c"], ["x", "c"])
+  call writefile(["a", "b", "c"], "Xdiin1")
+  call writefile(["x", "c"], "Xdinew1")
+  call writefile(["1c1", "2d1"], "Xdiout1")
+  call term_sendkeys(buf, ":set diffexpr=DiffExprStub()\<CR>:")
+  call VerifyBoth(buf, "Test_diff_overlapped_2.02", "")
+  call term_sendkeys(buf, ":set diffexpr&\<CR>:")
+
+  call WriteDiffFiles(buf, ["a", "c"], ["x", "x", "c"])
+  call writefile(["a", "c"], "Xdiin1")
+  call writefile(["x", "x", "c"], "Xdinew1")
+  call writefile(["1c1", "1a2"], "Xdiout1")
+  call term_sendkeys(buf, ":set diffexpr=DiffExprStub()\<CR>:")
+  call VerifyBoth(buf, "Test_diff_overlapped_2.03", "")
+  call term_sendkeys(buf, ":set diffexpr&\<CR>:")
+
+  call StopVimInTerminal(buf)
+  wincmd c
+
+  call WriteDiffFiles3(0, [], [], [])
+  let buf = RunVimInTerminal('-d -S XdiffSetup Xdifile1 Xdifile2 Xdifile3', {})
+  call term_sendkeys(buf, ":set autoread\<CR>\<c-w>w:set autoread\<CR>\<c-w>w:set autoread\<CR>\<c-w>w")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], ["y", "b", "c"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.01", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], ["a", "y", "c"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.02", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], ["a", "b", "y"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.03", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], ["y", "y", "c"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.04", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], ["a", "y", "y"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.05", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], ["y", "y", "y"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.06", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "x"], ["y", "y", "c"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.07", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["x", "x", "c"], ["a", "y", "y"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.08", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["y", "y", "y", "d", "e"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.09", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["y", "y", "y", "y", "e"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.10", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["y", "y", "y", "y", "y"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.11", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["a", "y", "y", "d", "e"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.12", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["a", "y", "y", "y", "e"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.13", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["a", "y", "y", "y", "y"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.14", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["a", "b", "y", "d", "e"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.15", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["a", "b", "y", "y", "e"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.16", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["a", "b", "y", "y", "y"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.17", "")
+
+  call WriteDiffFiles3(buf, ["a", "b"], ["x", "b"], ["y", "y"])
+  call writefile(["a", "b"], "Xdiin1")
+  call writefile(["x", "b"], "Xdinew1")
+  call writefile(["1c1"], "Xdiout1")
+  call writefile(["a", "b"], "Xdiin2")
+  call writefile(["y", "y"], "Xdinew2")
+  call writefile(["1c1", "2c2"], "Xdiout2")
+  call term_sendkeys(buf, ":set diffexpr=DiffExprStub()\<CR>:")
+  call VerifyInternal(buf, "Test_diff_overlapped_3.18", "")
+  call term_sendkeys(buf, ":set diffexpr&\<CR>:")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d"], ["x", "b", "x", "d"], ["y", "y", "c", "d"])
+  call writefile(["a", "b", "c", "d"], "Xdiin1")
+  call writefile(["x", "b", "x", "d"], "Xdinew1")
+  call writefile(["1c1", "3c3"], "Xdiout1")
+  call writefile(["a", "b", "c", "d"], "Xdiin2")
+  call writefile(["y", "y", "c", "d"], "Xdinew2")
+  call writefile(["1c1", "2c2"], "Xdiout2")
+  call term_sendkeys(buf, ":set diffexpr=DiffExprStub()\<CR>:")
+  call VerifyInternal(buf, "Test_diff_overlapped_3.19", "")
+  call term_sendkeys(buf, ":set diffexpr&\<CR>:")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d"], ["x", "b", "x", "d"], ["y", "y", "y", "d"])
+  call writefile(["a", "b", "c", "d"], "Xdiin1")
+  call writefile(["x", "b", "x", "d"], "Xdinew1")
+  call writefile(["1c1", "3c3"], "Xdiout1")
+  call writefile(["a", "b", "c", "d"], "Xdiin2")
+  call writefile(["y", "y", "y", "d"], "Xdinew2")
+  call writefile(["1c1", "2,3c2,3"], "Xdiout2")
+  call term_sendkeys(buf, ":set diffexpr=DiffExprStub()\<CR>:")
+  call VerifyInternal(buf, "Test_diff_overlapped_3.20", "")
+  call term_sendkeys(buf, ":set diffexpr&\<CR>:")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d"], ["x", "b", "x", "d"], ["y", "y", "y", "y"])
+  call writefile(["a", "b", "c", "d"], "Xdiin1")
+  call writefile(["x", "b", "x", "d"], "Xdinew1")
+  call writefile(["1c1", "3c3"], "Xdiout1")
+  call writefile(["a", "b", "c", "d"], "Xdiin2")
+  call writefile(["y", "y", "y", "y"], "Xdinew2")
+  call writefile(["1c1", "2,4c2,4"], "Xdiout2")
+  call term_sendkeys(buf, ":set diffexpr=DiffExprStub()\<CR>:")
+  call VerifyInternal(buf, "Test_diff_overlapped_3.21", "")
+  call term_sendkeys(buf, ":set diffexpr&\<CR>:")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], ["b", "c"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.22", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], ["c"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.23", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], [])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.24", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], ["a", "c"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.25", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], ["a"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.26", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], ["b"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.27", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["d", "e"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.28", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["e"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.29", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["a", "d", "e"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.30", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["a", "e"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.31", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["a"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.32", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["a", "b", "d", "e"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.33", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["a", "b", "e"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.34", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c", "d", "e"], ["a", "x", "c", "x", "e"], ["a", "b"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.35", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], ["a", "y", "b", "c"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.36", "")
+
+  call WriteDiffFiles3(buf, ["a", "b", "c"], ["a", "x", "c"], ["a", "b", "y", "c"])
+  call VerifyBoth(buf, "Test_diff_overlapped_3.37", "")
+
+  call StopVimInTerminal(buf)
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab