2 files changed, 27 insertions, 6 deletions
diff --git a/build/plugins/pybuild.py b/build/plugins/pybuild.py
index 744449d109..229d4b1665 100644
--- a/build/plugins/pybuild.py
+++ b/build/plugins/pybuild.py
@@ -8,7 +8,6 @@ import ymake
 from _common import stripext, rootrel_arc_src, listid, pathid, lazy, get_no_lint_value, ugly_conftest_exception
 
 
-YA_IDE_VENV_VAR = 'YA_IDE_VENV'
 PY_NAMESPACE_PREFIX = 'py/namespace'
 BUILTIN_PROTO = 'builtin_proto'
 DEFAULT_FLAKE8_FILE_PROCESSING_TIME = "1.5"  # in seconds
@@ -37,8 +36,8 @@ def is_extended_source_search_enabled(path, unit):
         return False
     if unit.get('NO_EXTENDED_SOURCE_SEARCH') == 'yes':
         return False
-    # contrib is unfriendly to extended source search
-    if unit.resolve_arc_path(path).startswith('$S/contrib/'):
+    # Python itself and contrib/python are unfriendly to extended source search
+    if unit.resolve_arc_path(path).startswith(('$S/contrib/python', '$S/contrib/tools/python3')):
         return False
     return True
 
@@ -252,7 +251,7 @@ def onpy_srcs(unit, *args):
     with_py = not unit.get('PYBUILD_NO_PY')
     with_pyc = not unit.get('PYBUILD_NO_PYC')
     in_proto_library = unit.get('PY_PROTO') or unit.get('PY3_PROTO')
-    venv = unit.get(YA_IDE_VENV_VAR)
+    external_py_files_mode = unit.get('EXTERNAL_PY_FILES') or unit.get('YA_IDE_VENV')
     need_gazetteer_peerdir = False
     trim = 0
 
@@ -542,10 +541,21 @@ def onpy_srcs(unit, *args):
         if py3:
             mod_list_md5 = md5()
             compress = False
+            resfs_mocks = []
+
             for path, mod in pys:
                 mod_list_md5.update(six.ensure_binary(mod))
-                if not (venv and is_extended_source_search_enabled(path, unit)):
-                    dest = 'py/' + mod.replace('.', '/') + '.py'
+                dest = 'py/' + mod.replace('.', '/') + '.py'
+                # In external_py_files mode we want to build python binaries without embedded python files.
+                # The application will still be able to load them from the file system.
+                # However, the import hook still needs meta information about the file locations to work correctly.
+                # That's why we manually register the files in resfs/src/resfs/file, but don't provide any actual files.
+                # For more info see:
+                # - library/python/runtime_py3
+                # - https://docs.yandex-team.ru/ya-make/manual/python/vars
+                if external_py_files_mode and is_extended_source_search_enabled(path, unit):
+                    resfs_mocks += ['-', 'resfs/src/resfs/file/' + dest + '=' + rootrel_arc_src(path, unit)]
+                else:
                     if with_py:
                         res += ['DEST', dest, path]
                     if with_pyc:
@@ -556,6 +566,9 @@ def onpy_srcs(unit, *args):
                     if not compress and ugly_conftest_exception(path):
                         compress = True
 
+            if resfs_mocks:
+                unit.onresource(['DONT_COMPRESS'] + resfs_mocks)
+
             if py_namespaces:
                 # Note: Add md5 to key to prevent key collision if two or more PY_SRCS() used in the same ya.make
                 ns_res = ['DONT_COMPRESS']
diff --git a/build/plugins/ytest.py b/build/plugins/ytest.py
index 4911034877..ef47c32835 100644
--- a/build/plugins/ytest.py
+++ b/build/plugins/ytest.py
@@ -790,13 +790,21 @@ def onadd_check_py_imports(fields, unit, *args):
     if unit.get("TIDY") == "yes":
         # graph changed for clang_tidy tests
         return
+
     if unit.get('NO_CHECK_IMPORTS_FOR_VALUE').strip() == "":
         return
+
     unit.onpeerdir(['library/python/testing/import_test'])
 
     dart_record = create_dart_record(fields, unit, (), {})
     dart_record[df.TestName.KEY] = 'pyimports'
     dart_record[df.ScriptRelPath.KEY] = 'py.imports'
+    # Import tests work correctly in this mode, but can slow down by 2-3 times,
+    # due to the fact that files need to be read from the file system.
+    # Therefore, we disable them, since the external-py-files mode is designed exclusively
+    # to speed up the short cycle of developing regular tests.
+    if unit.get('EXTERNAL_PY_FILES'):
+        dart_record[df.SkipTest.KEY] = 'Import tests disabled in external-py-files mode'
 
     data = dump_test(unit, dart_record)
     if data: