[lldb][Interpreter] Add newline terminal to one-line script calls

[kastiglione]

Summary

Fix script -lpython to handle control flow in one-line commands.

The fix is to append a newline to the source being evaluated.

Without this patch, the following commands print no output, no errors.

(lldb) script if "foo" in lldb.frame.name: print(lldb.thread)
(lldb) script for f in lldb.thread: print(f.name)

The issue is with code.InteractiveConsole.runsource(). A trailing newline is
needed for these expressions to be evaluated. I don't know why this is, the
docs don't mention anything.

From a python repl, the following samples show that a terminal newline allows
statements containing flow control to fully execute.

>>> import code
>>> repl = code.InteractiveConsole()
>>> repl.runsource("if True: print(1)")
True
>>> repl.runsource("if True: print(1)\n")
1
False

Notes:

From an interactive python repl, the output is not printed immediately. The
user is required to enter a blank line following the first.

>>> if True: print(1)
... 
1

However, python -c 'if True: print(1)' works without needing a newline.

[JDevlieghere]

LGTM

[mib]

A bit late to this ... thanks for your fix!

lldb/source/Interpreter/embedded_interpreter.py

 
 
 def run_one_line(local_dict, input_string):
     global g_run_one_line_str
     try:
         input_string = strip_and_check_exit(input_string)
         repl = code.InteractiveConsole(local_dict)
         if input_string:
+            # A newline is appended to support one-line statements containing
+            # control flow. For example "if True: print(1)" silently does
+            # nothing, but works with a newline: "if True: print(1)\n".
+            input_string += "\n"
             repl.runsource(input_string)
         elif g_run_one_line_str:
             repl.runsource(g_run_one_line_str)
     except LLDBExit:
         pass
     except SystemExit as e:
         if e.code:
             print('Script exited with code %s' % e.code)

lldb/test/Shell/ScriptInterpreter/Python/python.test

 # RUN: %lldb --script-language python -o 'script print("{}".format(1000+100+10+1))' 2>&1 | FileCheck %s
 # RUN: %lldb --script-language python -o 'script -- print("{}".format(1000+100+10+1))' 2>&1 | FileCheck %s
 # RUN: %lldb --script-language python -o 'script --language default -- print("{}".format(1000+100+10+1))' 2>&1 | FileCheck %s
 # RUN: %lldb -o 'script -l python -- print("{}".format(1000+100+10+1))' 2>&1 | FileCheck %s
 # RUN: %lldb -o 'script -lpython -- print("{}".format(1000+100+10+1))' 2>&1 | FileCheck %s
 # RUN: %lldb -o 'script --language python -- print("{}".format(1000+100+10+1))' 2>&1 | FileCheck %s
 # RUN: %lldb -o 'script --language=python -- print("{}".format(1000+100+10+1))' 2>&1 | FileCheck %s
+# RUN: %lldb -o 'script -lpython -- if True: print("{}".format(1000+100+10+1))' 2>&1 | FileCheck %s
 # CHECK: 1111
 
 # RUN: %lldb -o 'script --language invalid -- print("{}".format(1000+100+10+1))' 2>&1 | FileCheck %s --check-prefix INVALID
 # INVALID: error: unrecognized value for language 'invalid'
 # INVALID-NOT: 1111