patch 9.0.1543: display errors when making topline shorterv9.0.1543

Problem:    Display errors when making topline shorter and 'smoothscroll' is
            set.
Solution:   Reset w_skipcol when the topline becomes shorter than its current
            value. (Luuk van Baal, closes #12367)

6 files changed, 41 insertions, 7 deletions

diff --git a/src/testdir/dumps/Test_display_long_line_1.dump b/src/testdir/dumps/Test_display_long_line_1.dump
index 691f358e9b..f2be2aa412 100644
--- a/src/testdir/dumps/Test_display_long_line_1.dump
+++ b/src/testdir/dumps/Test_display_long_line_1.dump
@@ -9,6 +9,6 @@
 @35
 @35
 @35
-@26>a@8
-@10| @24
-@18|1|,|4|8|2| @7|T|o|p| 
+@35
+>a@14| @19
+@18|1|,|7|3|6| @7|T|o|p| 
diff --git a/src/testdir/dumps/Test_display_long_line_2.dump b/src/testdir/dumps/Test_display_long_line_2.dump
index dcf6e275bd..25b5e89786 100644
--- a/src/testdir/dumps/Test_display_long_line_2.dump
+++ b/src/testdir/dumps/Test_display_long_line_2.dump
@@ -9,6 +9,6 @@
 @35
 @35
 @35
-@25>a| @8
+@34>a
 |b@4| |b@4| |b@4| |b@4| |b@4| |b@1|@+0#4040ff13&@2
-| +0#0000000&@17|1|,|4|8|1| @7|T|o|p| 
+| +0#0000000&@17|1|,|7|3|5| @7|T|o|p| 
diff --git a/src/testdir/dumps/Test_display_long_line_3.dump b/src/testdir/dumps/Test_display_long_line_3.dump
new file mode 100644
index 0000000000..7f8c173582
--- /dev/null
+++ b/src/testdir/dumps/Test_display_long_line_3.dump
@@ -0,0 +1,14 @@
+|<+0#4040ff13#ffffff0@2>a+0#0000000&| @30
+|b@4| |b@4| |b@4| |b@4| |b@4| |b@4
+| |b@4| |c@4| |c@4| |c@4| |c@4| |c@3
+@1| |c@4| |c@4| |d@4| |d@4| |d@4| |d@2
+@2| |d@4| |d@4| |d@4| @14
+|~+0#4040ff13&| @33
+|~| @33
+|~| @33
+|~| @33
+|~| @33
+|~| @33
+|~| @33
+|~| @33
+| +0#0000000&@17|1|,|3|1|9| @7|A|l@1| 
diff --git a/src/testdir/dumps/Test_display_long_line_4.dump b/src/testdir/dumps/Test_display_long_line_4.dump
new file mode 100644
index 0000000000..8bdb4d50fc
--- /dev/null
+++ b/src/testdir/dumps/Test_display_long_line_4.dump
@@ -0,0 +1,14 @@
+|a+0&#ffffff0@34
+@35
+@35
+@35
+@35
+@35
+@35
+@35
+@35
+@2>a| @31
+|b@4| |b@4| |b@4| |b@4| |b@4| |b@4
+| |b@4| |c@4| |c@4| |c@4| |c@4| |c@3
+@1| |c@4| |c@4| |d@4| |d@4| |d@4| |@+0#4040ff13&@2
+| +0#0000000&@17|1|,|3|1|8| @7|T|o|p| 
diff --git a/src/testdir/dumps/Test_smooth_long_15.dump b/src/testdir/dumps/Test_smooth_long_15.dump
index b82fca5994..7f5bff746c 100644
--- a/src/testdir/dumps/Test_smooth_long_15.dump
+++ b/src/testdir/dumps/Test_smooth_long_15.dump
@@ -2,5 +2,5 @@
 |h| |l|o|t|s| |o|f| |t|e|x|t| |w|i|t|h| |l|o|t|s| |o|f| |t|e|x|t| |w|i|t|h| |l|o
 |t|s| |o|f| |t|e|x|t| |w|i|t|h| |l|o|t|s| |o|f| |t|e|x|t| |w|i|t|h| |l|o|t|s| |o
 |f| |t|e|x|t| |w|i|t|h| |l|o|t|s| |o|f| |t|e|x|t| |e|n|d| @11
-|f|o|u>r| @35
-@22|4|,|4| @10|B|o|t| 
+>f|o|u|r| @35
+@22|4|,|1| @10|B|o|t| 
diff --git a/src/testdir/dumps/Test_smooth_long_16.dump b/src/testdir/dumps/Test_smooth_long_16.dump
new file mode 100644
index 0000000000..b82fca5994
--- /dev/null
+++ b/src/testdir/dumps/Test_smooth_long_16.dump
@@ -0,0 +1,6 @@
+|<+0#4040ff13#ffffff0@2|t+0#0000000&|h| |l|o|t|s| |o|f| |t|e|x|t| |w|i|t|h| |l|o|t|s| |o|f| |t|e|x|t| |w|i|t
+|h| |l|o|t|s| |o|f| |t|e|x|t| |w|i|t|h| |l|o|t|s| |o|f| |t|e|x|t| |w|i|t|h| |l|o
+|t|s| |o|f| |t|e|x|t| |w|i|t|h| |l|o|t|s| |o|f| |t|e|x|t| |w|i|t|h| |l|o|t|s| |o
+|f| |t|e|x|t| |w|i|t|h| |l|o|t|s| |o|f| |t|e|x|t| |e|n|d| @11
+|f|o|u>r| @35
+@22|4|,|4| @10|B|o|t|