Fix executing from stdin

Author: msimacek

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

@@ -621,7 +621,7 @@ protected void launch(Builder contextBuilder) {
             }
             consoleHandler.setContext(context);
 
-            if (commandString != null || inputFile != null) {
+            if (commandString != null || inputFile != null || !stdinIsInteractive) {
                 try {
                     evalNonInteractive(context, consoleHandler);
                     rc = 0;
@@ -722,8 +722,7 @@ private void evalNonInteractive(Context context, ConsoleHandler consoleHandler)
         if (commandString != null) {
             src = Source.newBuilder(getLanguageId(), commandString, "<string>").build();
         } else {
-            assert inputFile != null;
-            // the path is passed through a context option
+            // the path is passed through a context option, may be empty when running from stdin
             src = Source.newBuilder(getLanguageId(), "__graalpython__.run_path()", "<internal>").internal(true).build();
         }
         context.eval(src);

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

@@ -50,6 +50,7 @@
 import static com.oracle.graal.python.runtime.exception.PythonErrorType.TypeError;
 
 import java.io.IOException;
+import java.io.InputStreamReader;
 import java.io.PrintWriter;
 import java.nio.charset.StandardCharsets;
 import java.util.List;
@@ -246,7 +247,7 @@ PNone run() {
             PythonContext context = getContext();
             String inputFilePath = context.getOption(PythonOptions.InputFilePath);
             PythonModule sysModule = context.getSysModule();
-            boolean needsMainImporter = getImporter(sysModule, inputFilePath);
+            boolean needsMainImporter = !inputFilePath.isEmpty() && getImporter(sysModule, inputFilePath);
             if (needsMainImporter) {
                 Object sysPath = sysModule.getAttribute("path");
                 PyObjectCallMethodObjArgs.getUncached().execute(null, sysPath, "insert", 0, inputFilePath);
@@ -264,11 +265,19 @@ PNone run() {
             return PNone.NONE;
         }
 
-        // Equivalent of CPython's pymain_run_file
+        // Equivalent of CPython's pymain_run_file and pymain_run_stdin
         private void runFile(PythonContext context, String inputFilePath) {
             Source source;
             try {
-                source = Source.newBuilder(PythonLanguage.ID, context.getPublicTruffleFileRelaxed(inputFilePath)).mimeType(PythonLanguage.MIME_TYPE).build();
+                Source.SourceBuilder builder;
+                if (inputFilePath.isEmpty()) {
+                    // Reading from stdin
+                    builder = Source.newBuilder(PythonLanguage.ID, new InputStreamReader(context.getStandardIn()), "<stdin>");
+                } else {
+                    TruffleFile file = context.getPublicTruffleFileRelaxed(inputFilePath);
+                    builder = Source.newBuilder(PythonLanguage.ID, file);
+                }
+                source = builder.mimeType(PythonLanguage.MIME_TYPE).build();
                 // TODO we should handle non-IO errors better
             } catch (IOException e) {
                 ErrorAndMessagePair error = OSErrorEnum.fromException(e);