patch 8.2.3394: filler lines are wrong when changing text in diff modev8.2.3394

Problem:    Filler lines are wrong when changing text in diff mode.
Solution:   Don't change the filler lines on every change.  Check
            scrollbinding when updating the filler lines. (closes #8809)

3 files changed, 64 insertions, 0 deletions

diff --git a/src/testdir/dumps/Test_diff_scroll_change_01.dump b/src/testdir/dumps/Test_diff_scroll_change_01.dump
new file mode 100644
index 000000000..886fe6088
--- /dev/null
+++ b/src/testdir/dumps/Test_diff_scroll_change_01.dump
@@ -0,0 +1,20 @@
+| +0#0000e05#a8a8a8255@1|-+0#4040ff13#afffff255@34||+1#0000000#ffffff0| +0#0000e05#a8a8a8255@1|6+0#0000000#5fd7ff255| @33
+| +0#0000e05#a8a8a8255@1|-+0#4040ff13#afffff255@34||+1#0000000#ffffff0| +0#0000e05#a8a8a8255@1|7+0#0000000#5fd7ff255| @33
+| +0#0000e05#a8a8a8255@1|-+0#4040ff13#afffff255@34||+1#0000000#ffffff0| +0#0000e05#a8a8a8255@1|8+0#0000000#5fd7ff255| @33
+| +0#0000e05#a8a8a8255@1|9+0#0000000#ffffff0| @33||+1&&| +0#0000e05#a8a8a8255@1|9+0#0000000#ffffff0| @33
+| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|0| @32||+1&&| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|0| @32
+| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0@1| @32||+1&&| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0@1| @32
+| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|2| @32||+1&&| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|2| @32
+| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|3| @32||+1&&| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|3| @32
+| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|4| @32||+1&&| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|4| @32
+|-+0#0000e05#a8a8a8255| |1+0#0000000#ffffff0>5| @32||+1&&|-+0#0000e05#a8a8a8255| |1+0#0000000#ffffff0|5| @32
+|~+0#4040ff13&| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|[+3#0000000&|N|o| |N|a|m|e|]| |[|+|]| @5|7|,|2| @11|A|l@1| |[+1&&|N|o| |N|a|m|e|]| |[|+|]| @5|1|5|,|2| @10|B|o|t
+| +0&&@74
diff --git a/src/testdir/dumps/Test_diff_scroll_change_02.dump b/src/testdir/dumps/Test_diff_scroll_change_02.dump
new file mode 100644
index 000000000..d699ded1f
--- /dev/null
+++ b/src/testdir/dumps/Test_diff_scroll_change_02.dump
@@ -0,0 +1,20 @@
+| +0#0000e05#a8a8a8255@1|-+0#4040ff13#afffff255@34||+1#0000000#ffffff0| +0#0000e05#a8a8a8255@1|6+0#0000000#5fd7ff255| @33
+| +0#0000e05#a8a8a8255@1|-+0#4040ff13#afffff255@34||+1#0000000#ffffff0| +0#0000e05#a8a8a8255@1|7+0#0000000#5fd7ff255| @33
+| +0#0000e05#a8a8a8255@1|-+0#4040ff13#afffff255@34||+1#0000000#ffffff0| +0#0000e05#a8a8a8255@1|8+0#0000000#5fd7ff255| @33
+| +0#0000e05#a8a8a8255@1|9+0#0000000#ffffff0| @33||+1&&| +0#0000e05#a8a8a8255@1|9+0#0000000#ffffff0| @33
+| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|0| @32||+1&&| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|0| @32
+| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0@1| @32||+1&&| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0@1| @32
+| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|2| @32||+1&&| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|2| @32
+| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|3| @32||+1&&| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|3| @32
+| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|4| @32||+1&&| +0#0000e05#a8a8a8255@1|1+0#0000000#ffffff0|4| @32
+| +0#0000e05#a8a8a8255@1|1+0#0000000#ffd7ff255|5>x+2&#ff404010| +0&#ffd7ff255@31||+1&#ffffff0| +0#0000e05#a8a8a8255@1|1+0#0000000#ffd7ff255|5| @32
+|~+0#4040ff13#ffffff0| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|~| @35||+1#0000000&|~+0#4040ff13&| @35
+|[+3#0000000&|N|o| |N|a|m|e|]| |[|+|]| @5|7|,|3| @11|A|l@1| |[+1&&|N|o| |N|a|m|e|]| |[|+|]| @5|1|5|,|3| @10|B|o|t
+| +0&&@74
diff --git a/src/testdir/test_diffmode.vim b/src/testdir/test_diffmode.vim
index 5400de6d3..268c3e9b5 100644
--- a/src/testdir/test_diffmode.vim
+++ b/src/testdir/test_diffmode.vim
@@ -993,6 +993,30 @@ func Test_diff_screen()
   call delete('XdiffSetup')
 endfunc
 
+func Test_diff_with_scroll_and_change()
+  CheckScreendump
+
+  let lines =<< trim END
+	call setline(1, range(1, 15))
+	vnew
+	call setline(1, range(9, 15))
+	windo diffthis
+	wincmd h
+	exe "normal Gl5\<C-E>"
+  END
+  call writefile(lines, 'Xtest_scroll_change')
+  let buf = RunVimInTerminal('-S Xtest_scroll_change', {})
+
+  call VerifyScreenDump(buf, 'Test_diff_scroll_change_01', {})
+
+  call term_sendkeys(buf, "ax\<Esc>")
+  call VerifyScreenDump(buf, 'Test_diff_scroll_change_02', {})
+
+  " clean up
+  call StopVimInTerminal(buf)
+  call delete('Xtest_scroll_change')
+endfunc
+
 func Test_diff_with_cursorline()
   CheckScreendump