[3.7] bpo-34247: Fix Python 3.7 initialization (#8659)

* -X dev: it is now possible to override the memory allocator using
  PYTHONMALLOC even if the developer mode is enabled.
* Add _Py_InitializeFromConfig()
* Add _Py_Initialize_ReadEnvVars() to set global configuration
  variables from environment variables
* Fix the code to initialize Python: Py_Initialize() now also reads
  environment variables
* _Py_InitializeCore() can now be called twice: the second call
  only replaces the configuration.
* Write unit tests on Py_Initialize() and the different ways to
  configure Python
* The isolated mode now always sets Py_IgnoreEnvironmentFlag and
  Py_NoUserSiteDirectory to 1.
* pymain_read_conf() now saves/restores the configuration
  if the encoding changed

2 files changed, 304 insertions, 3 deletions

diff --git a/Programs/_freeze_importlib.c b/Programs/_freeze_importlib.c
index b8b630cfed..7de641e1a5 100644
--- a/Programs/_freeze_importlib.c
+++ b/Programs/_freeze_importlib.c
@@ -74,18 +74,25 @@ main(int argc, char *argv[])
     }
     text[text_size] = '\0';
 
+    _PyCoreConfig config = _PyCoreConfig_INIT;
+    config.program_name = L"./_freeze_importlib";
+    /* Don't install importlib, since it could execute outdated bytecode. */
+    config._disable_importlib = 1;
+
     Py_NoUserSiteDirectory++;
     Py_NoSiteFlag++;
     Py_IgnoreEnvironmentFlag++;
     Py_FrozenFlag++;
 
-    Py_SetProgramName(L"./_freeze_importlib");
-    /* Don't install importlib, since it could execute outdated bytecode. */
-    _PyInitError err = _Py_InitializeEx_Private(1, 0);
+
+    _PyInitError err = _Py_InitializeFromConfig(&config);
+    /* No need to call _PyCoreConfig_Clear() since we didn't allocate any
+       memory: program_name is a constant string. */
     if (_Py_INIT_FAILED(err)) {
         _Py_FatalInitError(err);
     }
 
+
     if (strstr(inpath, "_external") != NULL) {
         is_bootstrap = 0;
     }
diff --git a/Programs/_testembed.c b/Programs/_testembed.c
index b1be682f7a..6c35f9586b 100644
--- a/Programs/_testembed.c
+++ b/Programs/_testembed.c
@@ -1,4 +1,5 @@
 #include <Python.h>
+#include "internal/import.h"
 #include "pythread.h"
 #include <inttypes.h>
 #include <stdio.h>
@@ -292,6 +293,293 @@ static int test_initialize_pymain(void)
 }
 
 
+static void
+dump_config(void)
+{
+#define ASSERT_EQUAL(a, b) \
+    if ((a) != (b)) { \
+        printf("ERROR: %s != %s (%i != %i)\n", #a, #b, (a), (b)); \
+        exit(1); \
+    }
+#define ASSERT_STR_EQUAL(a, b) \
+    if ((a) == NULL || (b == NULL) || wcscmp((a), (b)) != 0) { \
+        printf("ERROR: %s != %s ('%ls' != '%ls')\n", #a, #b, (a), (b)); \
+        exit(1); \
+    }
+
+    PyInterpreterState *interp = PyThreadState_Get()->interp;
+    _PyCoreConfig *config = &interp->core_config;
+
+    printf("install_signal_handlers = %i\n", config->install_signal_handlers);
+
+    printf("Py_IgnoreEnvironmentFlag = %i\n", Py_IgnoreEnvironmentFlag);
+
+    printf("use_hash_seed = %i\n", config->use_hash_seed);
+    printf("hash_seed = %lu\n", config->hash_seed);
+
+    printf("allocator = %s\n", config->allocator);
+
+    printf("dev_mode = %i\n", config->dev_mode);
+    printf("faulthandler = %i\n", config->faulthandler);
+    printf("tracemalloc = %i\n", config->tracemalloc);
+    printf("import_time = %i\n", config->import_time);
+    printf("show_ref_count = %i\n", config->show_ref_count);
+    printf("show_alloc_count = %i\n", config->show_alloc_count);
+    printf("dump_refs = %i\n", config->dump_refs);
+    printf("malloc_stats = %i\n", config->malloc_stats);
+
+    printf("coerce_c_locale = %i\n", config->coerce_c_locale);
+    printf("coerce_c_locale_warn = %i\n", config->coerce_c_locale_warn);
+    printf("utf8_mode = %i\n", config->utf8_mode);
+
+    printf("program_name = %ls\n", config->program_name);
+    ASSERT_STR_EQUAL(config->program_name, Py_GetProgramName());
+
+    printf("argc = %i\n", config->argc);
+    printf("argv = [");
+    for (int i=0; i < config->argc; i++) {
+        if (i) {
+            printf(", ");
+        }
+        printf("\"%ls\"", config->argv[i]);
+    }
+    printf("]\n");
+
+    printf("program = %ls\n", config->program);
+    /* FIXME: test xoptions */
+    /* FIXME: test warnoptions */
+    /* FIXME: test module_search_path_env */
+    /* FIXME: test home */
+    /* FIXME: test module_search_paths */
+    /* FIXME: test executable */
+    /* FIXME: test prefix */
+    /* FIXME: test base_prefix */
+    /* FIXME: test exec_prefix */
+    /* FIXME: test base_exec_prefix */
+    /* FIXME: test dll_path */
+
+    printf("Py_IsolatedFlag = %i\n", Py_IsolatedFlag);
+    printf("Py_NoSiteFlag = %i\n", Py_NoSiteFlag);
+    printf("Py_BytesWarningFlag = %i\n", Py_BytesWarningFlag);
+    printf("Py_InspectFlag = %i\n", Py_InspectFlag);
+    printf("Py_InteractiveFlag = %i\n", Py_InteractiveFlag);
+    printf("Py_OptimizeFlag = %i\n", Py_OptimizeFlag);
+    printf("Py_DebugFlag = %i\n", Py_DebugFlag);
+    printf("Py_DontWriteBytecodeFlag = %i\n", Py_DontWriteBytecodeFlag);
+    printf("Py_VerboseFlag = %i\n", Py_VerboseFlag);
+    printf("Py_QuietFlag = %i\n", Py_QuietFlag);
+    printf("Py_NoUserSiteDirectory = %i\n", Py_NoUserSiteDirectory);
+    printf("Py_UnbufferedStdioFlag = %i\n", Py_UnbufferedStdioFlag);
+    /* FIXME: test legacy_windows_fs_encoding */
+    /* FIXME: test legacy_windows_stdio */
+
+    printf("_disable_importlib = %i\n", config->_disable_importlib);
+    /* cannot test _Py_CheckHashBasedPycsMode: the symbol is not exported */
+    printf("Py_FrozenFlag = %i\n", Py_FrozenFlag);
+
+#undef ASSERT_EQUAL
+#undef ASSERT_STR_EQUAL
+}
+
+
+static int test_init_default_config(void)
+{
+    _testembed_Py_Initialize();
+    dump_config();
+    Py_Finalize();
+    return 0;
+}
+
+
+static int test_init_global_config(void)
+{
+    /* FIXME: test Py_IgnoreEnvironmentFlag */
+
+    putenv("PYTHONUTF8=0");
+    Py_UTF8Mode = 1;
+
+    /* Test initialization from global configuration variables (Py_xxx) */
+    Py_SetProgramName(L"./globalvar");
+
+    /* Py_IsolatedFlag is not tested */
+    Py_NoSiteFlag = 1;
+    Py_BytesWarningFlag = 1;
+
+    putenv("PYTHONINSPECT=");
+    Py_InspectFlag = 1;
+
+    putenv("PYTHONOPTIMIZE=0");
+    Py_InteractiveFlag = 1;
+
+    putenv("PYTHONDEBUG=0");
+    Py_OptimizeFlag = 2;
+
+    /* Py_DebugFlag is not tested */
+
+    putenv("PYTHONDONTWRITEBYTECODE=");
+    Py_DontWriteBytecodeFlag = 1;
+
+    putenv("PYTHONVERBOSE=0");
+    Py_VerboseFlag = 1;
+
+    Py_QuietFlag = 1;
+    Py_NoUserSiteDirectory = 1;
+
+    putenv("PYTHONUNBUFFERED=");
+    Py_UnbufferedStdioFlag = 1;
+
+    Py_FrozenFlag = 1;
+
+    /* FIXME: test Py_LegacyWindowsFSEncodingFlag */
+    /* FIXME: test Py_LegacyWindowsStdioFlag */
+
+    Py_Initialize();
+    dump_config();
+    Py_Finalize();
+    return 0;
+}
+
+
+static int test_init_from_config(void)
+{
+    /* Test _Py_InitializeFromConfig() */
+    _PyCoreConfig config = _PyCoreConfig_INIT;
+    config.install_signal_handlers = 0;
+
+    /* FIXME: test ignore_environment */
+
+    putenv("PYTHONHASHSEED=42");
+    config.use_hash_seed = 1;
+    config.hash_seed = 123;
+
+    putenv("PYTHONMALLOC=malloc");
+    config.allocator = "malloc_debug";
+
+    /* dev_mode=1 is tested in test_init_dev_mode() */
+
+    putenv("PYTHONFAULTHANDLER=");
+    config.faulthandler = 1;
+
+    putenv("PYTHONTRACEMALLOC=0");
+    config.tracemalloc = 2;
+
+    putenv("PYTHONPROFILEIMPORTTIME=0");
+    config.import_time = 1;
+
+    config.show_ref_count = 1;
+    config.show_alloc_count = 1;
+    /* FIXME: test dump_refs: bpo-34223 */
+
+    putenv("PYTHONMALLOCSTATS=0");
+    config.malloc_stats = 1;
+
+    /* FIXME: test coerce_c_locale and coerce_c_locale_warn */
+
+    putenv("PYTHONUTF8=0");
+    Py_UTF8Mode = 0;
+    config.utf8_mode = 1;
+
+    Py_SetProgramName(L"./globalvar");
+    config.program_name = L"./conf_program_name";
+
+    /* FIXME: test argc/argv */
+    config.program = L"conf_program";
+    /* FIXME: test xoptions */
+    /* FIXME: test warnoptions */
+    /* FIXME: test module_search_path_env */
+    /* FIXME: test home */
+    /* FIXME: test path config: module_search_path .. dll_path */
+
+    _PyInitError err = _Py_InitializeFromConfig(&config);
+    /* Don't call _PyCoreConfig_Clear() since all strings are static */
+    if (_Py_INIT_FAILED(err)) {
+        _Py_FatalInitError(err);
+    }
+    dump_config();
+    Py_Finalize();
+    return 0;
+}
+
+
+static void test_init_env_putenvs(void)
+{
+    putenv("PYTHONHASHSEED=42");
+    putenv("PYTHONMALLOC=malloc_debug");
+    putenv("PYTHONTRACEMALLOC=2");
+    putenv("PYTHONPROFILEIMPORTTIME=1");
+    putenv("PYTHONMALLOCSTATS=1");
+    putenv("PYTHONUTF8=1");
+    putenv("PYTHONVERBOSE=1");
+    putenv("PYTHONINSPECT=1");
+    putenv("PYTHONOPTIMIZE=2");
+    putenv("PYTHONDONTWRITEBYTECODE=1");
+    putenv("PYTHONUNBUFFERED=1");
+    putenv("PYTHONNOUSERSITE=1");
+    putenv("PYTHONFAULTHANDLER=1");
+    putenv("PYTHONDEVMODE=1");
+    /* FIXME: test PYTHONWARNINGS */
+    /* FIXME: test PYTHONEXECUTABLE */
+    /* FIXME: test PYTHONHOME */
+    /* FIXME: test PYTHONDEBUG */
+    /* FIXME: test PYTHONDUMPREFS */
+    /* FIXME: test PYTHONCOERCECLOCALE */
+    /* FIXME: test PYTHONPATH */
+}
+
+
+static int test_init_env(void)
+{
+    /* Test initialization from environment variables */
+    Py_IgnoreEnvironmentFlag = 0;
+    test_init_env_putenvs();
+    _testembed_Py_Initialize();
+    dump_config();
+    Py_Finalize();
+    return 0;
+}
+
+
+static int test_init_isolated(void)
+{
+    /* Test _PyCoreConfig.isolated=1 */
+    _PyCoreConfig config = _PyCoreConfig_INIT;
+
+    /* Set coerce_c_locale and utf8_mode to not depend on the locale */
+    config.coerce_c_locale = 0;
+    config.utf8_mode = 0;
+    /* Use path starting with "./" avoids a search along the PATH */
+    config.program_name = L"./_testembed";
+
+    Py_IsolatedFlag = 1;
+
+    test_init_env_putenvs();
+    _PyInitError err = _Py_InitializeFromConfig(&config);
+    if (_Py_INIT_FAILED(err)) {
+        _Py_FatalInitError(err);
+    }
+    dump_config();
+    Py_Finalize();
+    return 0;
+}
+
+
+static int test_init_dev_mode(void)
+{
+    _PyCoreConfig config = _PyCoreConfig_INIT;
+    putenv("PYTHONFAULTHANDLER=");
+    putenv("PYTHONMALLOC=");
+    config.dev_mode = 1;
+    config.program_name = L"./_testembed";
+    _PyInitError err = _Py_InitializeFromConfig(&config);
+    if (_Py_INIT_FAILED(err)) {
+        _Py_FatalInitError(err);
+    }
+    dump_config();
+    Py_Finalize();
+    return 0;
+}
+
+
 /* *********************************************************
  * List of test cases and the function that implements it.
  *
@@ -318,6 +606,12 @@ static struct TestCase TestCases[] = {
     { "bpo20891", test_bpo20891 },
     { "initialize_twice", test_initialize_twice },
     { "initialize_pymain", test_initialize_pymain },
+    { "init_default_config", test_init_default_config },
+    { "init_global_config", test_init_global_config },
+    { "init_from_config", test_init_from_config },
+    { "init_env", test_init_env },
+    { "init_dev_mode", test_init_dev_mode },
+    { "init_isolated", test_init_isolated },
     { NULL, NULL }
 };