gh-113744: Add a new IncompleteInputError exception to improve incomplete input detection in the codeop module

Signed-off-by: Pablo Galindo <pablogsal@gmail.com>

Author: pablogsal

Include/pyerrors.h

@@ -108,6 +108,7 @@ PyAPI_DATA(PyObject *) PyExc_NotImplementedError;
 PyAPI_DATA(PyObject *) PyExc_SyntaxError;
 PyAPI_DATA(PyObject *) PyExc_IndentationError;
 PyAPI_DATA(PyObject *) PyExc_TabError;
+PyAPI_DATA(PyObject *) PyExc_IncompleteInputError;
 PyAPI_DATA(PyObject *) PyExc_ReferenceError;
 PyAPI_DATA(PyObject *) PyExc_SystemError;
 PyAPI_DATA(PyObject *) PyExc_SystemExit;

Lib/_compat_pickle.py

@@ -87,6 +87,7 @@
     ('urllib', 'urlretrieve'): ('urllib.request', 'urlretrieve'),
     ('urllib2', 'HTTPError'): ('urllib.error', 'HTTPError'),
     ('urllib2', 'URLError'): ('urllib.error', 'URLError'),
+    ('exceptions', 'IncompleteInputError'): ('builtins', 'IncompleteInputError'),
 }
 
 PYTHON2_EXCEPTIONS = (

Lib/codeop.py

@@ -65,9 +65,10 @@ def _maybe_compile(compiler, source, filename, symbol):
             try:
                 compiler(source + "\n", filename, symbol)
                 return None
+            except IncompleteInputError as e:
+                return None
             except SyntaxError as e:
-                if "incomplete input" in str(e):
-                    return None
+                pass
                 # fallthrough
 
     return compiler(source, filename, symbol, incomplete_input=False)

Lib/test/exception_hierarchy.txt

@@ -44,6 +44,7 @@ BaseException
       ├── StopAsyncIteration
       ├── StopIteration
       ├── SyntaxError
+      │    └── IncompleteInputError
       │    └── IndentationError
       │         └── TabError
       ├── SystemError

Objects/exceptions.c

@@ -2566,6 +2566,11 @@ MiddlingExtendsException(PyExc_SyntaxError, IndentationError, SyntaxError,
 MiddlingExtendsException(PyExc_IndentationError, TabError, SyntaxError,
                          "Improper mixture of spaces and tabs.");
 
+/*
+ *    IncompleteInputError extends SyntaxError
+ */
+MiddlingExtendsException(PyExc_SyntaxError, IncompleteInputError, SyntaxError,
+                         "incomplete input.");
 
 /*
  *    LookupError extends Exception
@@ -3635,6 +3640,7 @@ static struct static_exception static_exceptions[] = {
 
     // Level 4: Other subclasses
     ITEM(IndentationError), // base: SyntaxError(Exception)
+    ITEM(IncompleteInputError), // base: SyntaxError(Exception)
     ITEM(IndexError),  // base: LookupError(Exception)
     ITEM(KeyError),  // base: LookupError(Exception)
     ITEM(ModuleNotFoundError), // base: ImportError(Exception)

Parser/pegen.c

@@ -844,7 +844,7 @@ _PyPegen_run_parser(Parser *p)
     if (res == NULL) {
         if ((p->flags & PyPARSE_ALLOW_INCOMPLETE_INPUT) &&  _is_end_of_source(p)) {
             PyErr_Clear();
-            return RAISE_SYNTAX_ERROR("incomplete input");
+            return _PyPegen_raise_error(p, PyExc_IncompleteInputError, 0, "incomplete input");
         }
         if (PyErr_Occurred() && !PyErr_ExceptionMatches(PyExc_SyntaxError)) {
             return NULL;