Fix last line not displayed when scrolling using Display, fixes #737

builtins/src/main/java/org/jline/builtins/ScreenTerminal.java

@@ -245,7 +245,7 @@ private void poke(int y, int x, long[] s) {
         int max = s.length;
         while (cur < max) {
             int nb = Math.min(width - x, max - cur);
-            System.arraycopy(s, 0, screen[y++], x, nb);
+            System.arraycopy(s, cur, screen[y++], x, nb);
             x = 0;
             cur += nb;
         }

terminal/src/main/java/org/jline/utils/Display.java

@@ -179,7 +179,7 @@ public void update(List<AttributedString> newLines, int targetCursorPos, boolean
 
         int lineIndex = 0;
         int currentPos = 0;
-        int numLines = Math.max(oldLines.size(), newLines.size());
+        int numLines = Math.min(rows, Math.max(oldLines.size(), newLines.size()));
         boolean wrapNeeded = false;
         while (lineIndex < numLines) {
             AttributedString oldLine =

terminal/src/test/java/org/jline/utils/DisplayTest.java

@@ -0,0 +1,211 @@
+/*
+ * Copyright (c) 2021, the original author or authors.
+ *
+ * This software is distributable under the BSD license. See the terms of the
+ * BSD license in the documentation provided with this software.
+ *
+ * https://opensource.org/licenses/BSD-3-Clause
+ */
+package org.jline.utils;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.charset.Charset;
+import java.nio.charset.CharsetDecoder;
+import java.nio.charset.CoderResult;
+import java.nio.charset.CodingErrorAction;
+import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.jline.terminal.Attributes;
+import org.jline.terminal.Size;
+import org.jline.terminal.Terminal;
+import org.jline.terminal.TerminalBuilder;
+import org.jline.terminal.impl.LineDisciplineTerminal;
+import org.junit.Test;
+
+import static org.jline.utils.InfoCmp.Capability.enter_ca_mode;
+import static org.jline.utils.InfoCmp.Capability.exit_ca_mode;
+import static org.junit.Assert.assertEquals;
+
+public class DisplayTest {
+
+    @Test
+    public void i737() throws IOException {
+        int rows = 10;
+        int cols = 25;
+        try (VirtualTerminal terminal = new VirtualTerminal("jline", "xterm", StandardCharsets.UTF_8, cols, rows)) {
+            Attributes savedAttributes = terminal.enterRawMode();
+            terminal.puts(enter_ca_mode);
+            int height = terminal.getHeight();
+
+            Display display = new Display(terminal, true);
+            display.resize(height, terminal.getWidth());
+
+            // Build Strings to displayed
+            List<AttributedString> lines1 = new ArrayList<>();
+            for (int i = 1; i < height + 1; i++) {
+                lines1.add(new AttributedString(String.format("%03d: %s", i, "Chaine de test...")));
+            }
+
+            List<AttributedString> lines2 = new ArrayList<>();
+            for (int i = 0; i < height; i++) {
+                lines2.add(new AttributedString(String.format("%03d: %s", i, "Chaine de test...")));
+            }
+
+            display.update(lines1, 0);
+
+            display.update(lines2, 0);
+
+            long[] screen = terminal.dump();
+            List<AttributedString> lines = new ArrayList<>();
+            for (int r = 0; r < rows; r++) {
+                AttributedStringBuilder sb = new AttributedStringBuilder();
+                for (int i = 0; i < cols; i++) {
+                    sb.append((char) screen[i + cols * r]);
+                }
+                lines.add(sb.toAttributedString());
+            }
+            assertEquals("009: Chaine de test...   ", lines.get(rows-1).toString());
+
+            terminal.setAttributes(savedAttributes);
+            terminal.puts(exit_ca_mode);
+        }
+    }
+
+    static class VirtualTerminal extends LineDisciplineTerminal {
+        private final ScreenTerminal virtual;
+        private final OutputStream masterInputOutput;
+        public VirtualTerminal(String name, String type, Charset encoding, int cols, int rows) throws IOException {
+            super(name, type, new DelegateOutputStream(), encoding);
+            setSize(new Size(cols, rows));
+            virtual = new ScreenTerminal(cols, rows);
+            ((DelegateOutputStream) masterOutput).output = new MasterOutputStream();
+            masterInputOutput = new OutputStream() {
+                @Override
+                public void write(int b) throws IOException {
+                    VirtualTerminal.this.processInputByte(b);
+                }
+            };
+        }
+
+        public long[] dump() {
+            long[] screen = new long[size.getRows() * size.getColumns()];
+            virtual.dump(screen, 0, 0, size.getRows(), size.getColumns(), null);
+            return screen;
+        }
+
+        private static class DelegateOutputStream extends OutputStream {
+            OutputStream output;
+
+            @Override
+            public void write(int b) throws IOException {
+                output.write(b);
+            }
+
+            @Override
+            public void write(byte[] b) throws IOException {
+                output.write(b);
+            }
+
+            @Override
+            public void write(byte[] b, int off, int len) throws IOException {
+                output.write(b, off, len);
+            }
+
+            @Override
+            public void flush() throws IOException {
+                output.flush();
+            }
+
+            @Override
+            public void close() throws IOException {
+                output.close();
+            }
+        }
+
+        private class MasterOutputStream extends OutputStream {
+            private final ByteArrayOutputStream buffer = new ByteArrayOutputStream();
+            private final CharsetDecoder decoder = Charset.defaultCharset().newDecoder()
+                    .onMalformedInput(CodingErrorAction.REPLACE)
+                    .onUnmappableCharacter(CodingErrorAction.REPLACE);
+
+            @Override
+            public synchronized void write(int b) {
+                buffer.write(b);
+            }
+
+            @Override
+            public void write(byte[] b, int off, int len) throws IOException {
+                buffer.write(b, off, len);
+            }
+
+            @Override
+            public synchronized void flush() throws IOException {
+                int size = buffer.size();
+                if (size > 0) {
+                    CharBuffer out;
+                    for (; ; ) {
+                        out = CharBuffer.allocate(size);
+                        ByteBuffer in = ByteBuffer.wrap(buffer.toByteArray());
+                        CoderResult result = decoder.decode(in, out, false);
+                        if (result.isOverflow()) {
+                            size *= 2;
+                        } else {
+                            buffer.reset();
+                            buffer.write(in.array(), in.arrayOffset(), in.remaining());
+                            break;
+                        }
+                    }
+                    if (out.position() > 0) {
+                        out.flip();
+                        virtual.write(out);
+                        masterInputOutput.write(virtual.read().getBytes());
+                    }
+                }
+            }
+
+            @Override
+            public void close() throws IOException {
+                flush();
+            }
+        }
+    }
+
+    public static void main(String[] args) throws InterruptedException, IOException {
+
+        try (Terminal terminal = TerminalBuilder.builder().build()) {
+            Attributes savedAttributes = terminal.enterRawMode();
+            terminal.puts(enter_ca_mode);
+            int height = terminal.getHeight();
+
+            Display display = new Display(terminal, true);
+            display.resize(height, terminal.getWidth());
+
+            // Build Strings to displayed
+            List<AttributedString> lines1 = new ArrayList<>();
+            for (int i = 1; i < height + 1; i++) {
+                lines1.add(new AttributedString(String.format("%03d: %s", i, "Chaine de test...")));
+            }
+
+            List<AttributedString> lines2 = new ArrayList<>();
+            for (int i = 0; i < height; i++) {
+                lines2.add(new AttributedString(String.format("%03d: %s", i, "Chaine de test...")));
+            }
+
+            // Display with tempo
+            display.update(lines1, 0);
+            Thread.sleep(3000);
+
+            display.update(lines2, 0);
+            Thread.sleep(3000);
+
+            terminal.setAttributes(savedAttributes);
+            terminal.puts(exit_ca_mode);
+        }
+    }
+}