patch 8.1.0562: parsing of 'diffopt' is slightly wrong

Problem:    Parsing of 'diffopt' is slightly wrong.
Solution:   Fix the parsing and add a test. (Jason Franklin, Christian
            Brabandt)

Author: brammool

src/diff.c

@@ -2173,6 +2173,7 @@ diffopt_changed(void)
     int		diff_flags_new = 0;
     int		diff_foldcolumn_new = 2;
     long	diff_algorithm_new = 0;
+    long	diff_indent_heuristic = 0;
     tabpage_T	*tp;
 
     p = p_dip;
@@ -2236,7 +2237,7 @@ diffopt_changed(void)
 	else if (STRNCMP(p, "indent-heuristic", 16) == 0)
 	{
 	    p += 16;
-	    diff_algorithm_new |= XDF_INDENT_HEURISTIC;
+	    diff_indent_heuristic = XDF_INDENT_HEURISTIC;
 	}
 	else if (STRNCMP(p, "internal", 8) == 0)
 	{
@@ -2276,6 +2277,8 @@ diffopt_changed(void)
 	    ++p;
     }
 
+    diff_algorithm_new |= diff_indent_heuristic;
+
     /* Can't have both "horizontal" and "vertical". */
     if ((diff_flags_new & DIFF_HORIZONTAL) && (diff_flags_new & DIFF_VERTICAL))
 	return FAIL;

src/testdir/dumps/Test_diff_09.dump

@@ -17,4 +17,4 @@
 | +0#0000e05#a8a8a8255@1| +0#0000000#ffffff0@3|{| @29||+1&&| +0#0000e05#a8a8a8255@1| +0#0000000#ffffff0@3|{| @29
 | +0#0000e05#a8a8a8255@1| +0#0000000#5fd7ff255@7|p|r|i|n|t|f|(|"|Y|o|u|r| |a|n|s|w|e|r| |i|s|:| |"|)|;||+1&#ffffff0| +0#0000e05#a8a8a8255@1|-+0#4040ff13#afffff255@34
 |X+3#0000000#ffffff0|f|i|l|e|1| @12|1|,|1| @11|T|o|p| |X+1&&|f|i|l|e|2| @12|1|,|1| @11|T|o|p
-|:+0&&|s|e|t| |d|i|f@1|o|p|t|+|=|a|l|g|o|r|i|t|h|m|:|p|a|t|i|e|n|c|e| @42
+|:+0&&|s|e|t| |d|i|f@1|o|p|t|+|=|a|l|g|o|r|i|t|h|m|:|h|i|s|t|o|g|r|a|m| @41

src/testdir/dumps/Test_diff_11.dump

@@ -17,4 +17,4 @@
 | +0#0000e05#a8a8a8255@1|~+0#4040ff13#ffffff0| @33||+1#0000000&| +0#0000e05#a8a8a8255@1|~+0#4040ff13#ffffff0| @33
 | +0#0000e05#a8a8a8255@1|~+0#4040ff13#ffffff0| @33||+1#0000000&| +0#0000e05#a8a8a8255@1|~+0#4040ff13#ffffff0| @33
 |X+3#0000000&|f|i|l|e|1| @12|1|,|0|-|1| @9|A|l@1| |X+1&&|f|i|l|e|2| @12|1|,|0|-|1| @9|A|l@1
-|:+0&&|s|e|t| |d|i|f@1|o|p|t|+|=|i|n|d|e|n|t|-|h|e|u|r|i|s|t|i|c| @44
+|:+0&&| @73

src/testdir/screendump.vim

@@ -103,6 +103,8 @@ func VerifyScreenDump(buf, filename, options, ...)
 
   let i = 0
   while 1
+    " leave some time for updating the original window
+    sleep 10m
     call delete(testfile)
     call term_dumpwrite(a:buf, testfile, a:options)
     if readfile(reference) == readfile(testfile)
@@ -113,12 +115,11 @@ func VerifyScreenDump(buf, filename, options, ...)
       " Leave the test file around for inspection.
       let msg = 'See dump file difference: call term_dumpdiff("' . testfile . '", "' . reference . '")'
       if a:0 == 1
-	let msg = a:1 . ': ' . msg
+        let msg = a:1 . ': ' . msg
       endif
       call assert_report(msg)
       return 1
     endif
-    sleep 10m
     let i += 1
   endwhile
   return 0

src/testdir/test_diffmode.vim

@@ -813,8 +813,16 @@ func Test_diff_screen()
   call term_sendkeys(buf, ":set diffopt+=internal\<cr>")
   call VerifyScreenDump(buf, 'Test_diff_10', {})
 
-  call term_sendkeys(buf, ":set diffopt+=indent-heuristic\<cr>")
-  call VerifyScreenDump(buf, 'Test_diff_11', {})
+  " Leave trailing : at commandline!
+  call term_sendkeys(buf, ":set diffopt+=indent-heuristic\<cr>:\<cr>")
+  call VerifyScreenDump(buf, 'Test_diff_11', {}, 'one')
+  " shouldn't matter, if indent-algorithm comes before or after the algorithm
+  call term_sendkeys(buf, ":set diffopt&\<cr>")
+  call term_sendkeys(buf, ":set diffopt+=indent-heuristic,algorithm:patience\<cr>:\<cr>")
+  call VerifyScreenDump(buf, 'Test_diff_11', {}, 'two')
+  call term_sendkeys(buf, ":set diffopt&\<cr>")
+  call term_sendkeys(buf, ":set diffopt+=algorithm:patience,indent-heuristic\<cr>:\<cr>")
+  call VerifyScreenDump(buf, 'Test_diff_11', {}, 'three')
 
   " Test 12: diff the same file
   call WriteDiffFiles(buf, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], [1, 2, 3, 4, 5, 6, 7, 8, 9, 10])

src/version.c

@@ -792,6 +792,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    562,
 /**/
     561,
 /**/