"""
Test that re-running a process from within the same target
after rebuilding the a dynamic library flushes the scratch
TypeSystems tied to that process.
"""

import lldb
from lldbsuite.test.lldbtest import *
from lldbsuite.test import lldbutil
from lldbsuite.test.decorators import *


def isUbuntu18_04():
    """
    Check if the host OS is Ubuntu 18.04.
    Derived from `platform.freedesktop_os_release` in Python 3.10.
    """
    for path in ("/etc/os-release", "/usr/lib/os-release"):
        if os.path.exists(path):
            with open(path) as f:
                contents = f.read()
            if "Ubuntu 18.04" in contents:
                return True

    return False


class TestRerunExprDylib(TestBase):
    @skipTestIfFn(isUbuntu18_04, bugnumber="rdar://103831050")
    @skipIfWindows
    def test(self):
        """
        Tests whether re-launching a process without destroying
        the owning target keeps invalid ASTContexts in the
        scratch AST's importer.

        We test this by:
        1. Evaluating an expression to import 'struct Foo' into
           the scratch AST
        2. Change the definition of 'struct Foo' and rebuild the dylib
        3. Re-launch the process
        4. Evaluate the same expression in (1). We expect to have only
           the latest definition of 'struct Foo' in the scratch AST.
        """

        DYLIB_NAME = 'foo'
        FULL_DYLIB_NAME = 'libfoo.dylib' if self.platformIsDarwin() else 'libfoo.so'

        # Build libfoo.dylib
        self.build(dictionary={'DYLIB_CXX_SOURCES':'lib.cpp',
                               'DYLIB_ONLY':'YES',
                               'DYLIB_NAME':DYLIB_NAME,
                               'USE_LIBDL':'1',
                               'LD_EXTRAS':'-L.'})

        # Build a.out
        self.build(dictionary={'EXE':'a.out',
                               'CXX_SOURCES':'main.cpp',
                               'USE_LIBDL':'1',
                               'CXXFLAGS_EXTRAS':f'-DLIB_NAME=\\"{FULL_DYLIB_NAME}\\"',
                               'LD_EXTRAS':'-L.'})

        exe = self.getBuildArtifact("a.out")
        target = self.dbg.CreateTarget(exe) 
        target.BreakpointCreateBySourceRegex('dlclose', lldb.SBFileSpec('main.cpp'))
        target.BreakpointCreateBySourceRegex('return', lldb.SBFileSpec('main.cpp'))
        process = target.LaunchSimple(None, None, self.get_process_working_directory())  

        self.expect_expr('*foo', result_type='Foo', result_children=[
                ValueCheck(name='m_val', value='42')
            ])

        # Delete the dylib to force make to rebuild it.
        remove_file(self.getBuildArtifact(FULL_DYLIB_NAME))

        # Re-build libfoo.dylib
        self.build(dictionary={'DYLIB_CXX_SOURCES':'rebuild.cpp',
                               'DYLIB_ONLY':'YES',
                               'DYLIB_NAME':DYLIB_NAME,
                               'USE_LIBDL':'1',
                               'LD_EXTRAS':'-L.'})

        # Rerun program within the same target
        process.Continue()
        process.Destroy()
        process = target.LaunchSimple(None, None, self.get_process_working_directory())  

        self.expect_expr('*foo', result_type='Foo', result_children=[
            ValueCheck(name='Base', children=[
                ValueCheck(name='m_base_val', value='42')
            ]),
            ValueCheck(name='m_derived_val', value='137')
        ])

        self.filecheck("target module dump ast", __file__)

        # The new definition 'struct Foo' is in the scratch AST
        # CHECK:      |-CXXRecordDecl {{.*}} struct Foo definition
        # CHECK:      | |-public 'Base'
        # CHECK-NEXT: | `-FieldDecl {{.*}} m_derived_val 'int'
        # CHECK-NEXT: `-CXXRecordDecl {{.*}} struct Base definition
        # CHECK:        `-FieldDecl {{.*}} m_base_val 'int'

        # ...but the original definition of 'struct Foo' is not in the scratch AST anymore
        # CHECK-NOT: FieldDecl {{.*}} m_val 'int'

