Fix running with TTY but without readline initialized

Author: msimacek

graalpython/com.oracle.graal.python.shell/src/com/oracle/graal/python/shell/JLineConsoleHandler.java

@@ -43,6 +43,10 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.Reader;
+import java.io.Writer;
+import java.nio.charset.Charset;
 import java.nio.file.Path;
 import java.time.Instant;
 import java.util.Collections;
@@ -69,11 +73,14 @@
 import org.graalvm.shadowed.org.jline.reader.impl.DefaultParser;
 import org.graalvm.shadowed.org.jline.terminal.Terminal;
 import org.graalvm.shadowed.org.jline.terminal.TerminalBuilder;
+import org.graalvm.shadowed.org.jline.utils.InputStreamReader;
 
 public class JLineConsoleHandler extends ConsoleHandler {
     private final InputStream inputStream;
     private final OutputStream outputStream;
     private LineReader reader;
+    private Reader fallbackReader;
+    private Writer fallbackWriter;
     private final LinkedList<String> lineBuffer = new LinkedList<>();
     private CompletionState completionState;
 
@@ -175,6 +182,49 @@ public static class CompletionState {
     // Used via interop
     @Override
     public String readLine(String prompt) {
+        if (reader == null) {
+            if (fallbackReader == null) {
+                Charset charset;
+                try {
+                    charset = Charset.forName(System.getProperty("stdin.encoding"));
+                } catch (Exception e) {
+                    charset = Charset.defaultCharset();
+                }
+                // Note: using InputStreamReader from jline.utils for truly unbuffered reads
+                fallbackReader = new InputStreamReader(inputStream, charset);
+            }
+            try {
+                if (prompt != null && !prompt.isEmpty()) {
+                    if (fallbackWriter == null) {
+                        fallbackWriter = new OutputStreamWriter(outputStream);
+                    }
+                    fallbackWriter.write(prompt);
+                    fallbackWriter.flush();
+                }
+                StringBuilder sb = new StringBuilder();
+                while (true) {
+                    int c = inputStream.read();
+                    if (c < 0) {
+                        // EOF
+                        if (!sb.isEmpty()) {
+                            break;
+                        }
+                        if (prompt != null) {
+                            fallbackWriter.write("\n");
+                            fallbackWriter.flush();
+                        }
+                        return null;
+                    } else if (c == '\n') {
+                        break;
+                    } else if (c != '\r') {
+                        sb.append((char) c);
+                    }
+                }
+                return sb.toString();
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        }
         if (lineBuffer.isEmpty()) {
             try {
                 String lines = reader.readLine(prompt);

graalpython/com.oracle.graal.python.test/src/tests/test_repl.py

@@ -85,7 +85,7 @@ def validate_repl(stdin, python_args=(), ignore_preamble=True):
             import termios
             termios.tcsetwinsize(pty_parent, (60, 80))
             proc = subprocess.Popen(
-                [sys.executable, '-I', *python_args],
+                [sys.executable, '-s', '-E', '-P', *python_args],
                 env=env,
                 stdin=pty_child,
                 stdout=pty_child,
@@ -151,6 +151,18 @@ def test_basic_repl():
         """))
 
 
+    def test_basic_repl_no_readline():
+        validate_repl(dedent("""\
+            >>> 1023 + 1
+            1024
+            >>> None
+            >>> "hello"
+            'hello'
+            >>> _
+            'hello'
+        """), python_args=['-I'])
+
+
     def test_continuation():
         validate_repl(dedent(r'''\
             >>> def foo():

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/modules/ReadlineModuleBuiltins.java

@@ -74,6 +74,7 @@
 import com.oracle.graal.python.runtime.GilNode;
 import com.oracle.graal.python.runtime.PythonContext;
 import com.oracle.graal.python.runtime.exception.PythonErrorType;
+import com.oracle.graal.python.util.PythonUtils;
 import com.oracle.truffle.api.CompilerDirectives.TruffleBoundary;
 import com.oracle.truffle.api.TruffleLogger;
 import com.oracle.truffle.api.dsl.Bind;
@@ -128,7 +129,10 @@ public void postInitialize(Python3Core core) {
     public static Object getConsoleHandlerIfInitialized(PythonContext context) {
         PythonModule module = context.lookupBuiltinModule(T_READLINE);
         if (module != null) {
-            return module.getModuleState(LocalData.class).consoleHandler;
+            LocalData moduleState = module.getModuleState(LocalData.class);
+            if (moduleState != null) {
+                return moduleState.consoleHandler;
+            }
         }
         return null;
     }
@@ -403,7 +407,7 @@ static Object getCompletionStateMember(PythonModule self, String member) {
                     }
                 }
             } catch (InteropException e) {
-                // Fall through
+                LOGGER.fine(() -> PythonUtils.formatJString("Exception in getting completion state member %s: %s", member, e));
             }
         }
         return null;
@@ -416,7 +420,7 @@ static int getCompletionStateIntMember(PythonModule self, String member, int def
             try {
                 return InteropLibrary.getUncached().asInt(idx);
             } catch (InteropException e) {
-                // Fall through
+                LOGGER.fine(() -> PythonUtils.formatJString("Exception in getting completion state member %s: %s", member, e));
             }
         }
         return defaultValue;
@@ -433,7 +437,7 @@ static Object get(PythonModule self) {
                 try {
                     return InteropLibrary.getUncached().asTruffleString(lineObj);
                 } catch (InteropException e) {
-                    // Fall through
+                    LOGGER.fine(() -> PythonUtils.formatJString("Exception in getting completion state member %s: %s", "line", e));
                 }
             }
             return T_EMPTY_STRING;