bpo-12458: Fix line numbers for multiline expressions. (GH-8774)

Lib/test/test_dis.py

@@ -124,7 +124,8 @@ dis_bug708901 = """\
               2 LOAD_CONST               1 (1)
 
 %3d           4 LOAD_CONST               2 (10)
-              6 CALL_FUNCTION            2
+
+%3d           6 CALL_FUNCTION            2
               8 GET_ITER
         >>   10 FOR_ITER                 4 (to 16)
              12 STORE_FAST               0 (res)
@@ -134,6 +135,7 @@ dis_bug708901 = """\
              18 RETURN_VALUE
 """ % (bug708901.__code__.co_firstlineno + 1,
        bug708901.__code__.co_firstlineno + 2,
+       bug708901.__code__.co_firstlineno + 1,
        bug708901.__code__.co_firstlineno + 3)
 
 
@@ -154,7 +156,8 @@ dis_bug1333982 = """\
              16 CALL_FUNCTION            1
 
 %3d          18 LOAD_CONST               4 (1)
-             20 BINARY_ADD
+
+%3d          20 BINARY_ADD
              22 CALL_FUNCTION            1
              24 RAISE_VARARGS            1
 
@@ -164,6 +167,7 @@ dis_bug1333982 = """\
        __file__,
        bug1333982.__code__.co_firstlineno + 1,
        bug1333982.__code__.co_firstlineno + 2,
+       bug1333982.__code__.co_firstlineno + 1,
        bug1333982.__code__.co_firstlineno + 3)
 
 _BIG_LINENO_FORMAT = """\

Lib/test/test_doctest.py

@@ -2719,7 +2719,7 @@ Check doctest with a non-ascii filename:
     Exception raised:
         Traceback (most recent call last):
           File ...
-            compileflags, 1), test.globs)
+            exec(compile(example.source, filename, "single",
           File "<doctest foo-bär@baz[0]>", line 1, in <module>
             raise Exception('clé')
         Exception: clé

Lib/test/test_faulthandler.py

@@ -400,7 +400,7 @@ class FaultHandlerTests(unittest.TestCase):
         if filename:
             lineno = 9
         elif fd is not None:
-            lineno = 12
+            lineno = 11
         else:
             lineno = 14
         expected = [

Lib/test/test_traceback.py

@@ -995,11 +995,11 @@ class TestStack(unittest.TestCase):
         s = some_inner(3, 4)
         self.assertEqual(
             ['  File "%s", line %d, in some_inner\n'
-             '    traceback.walk_stack(None), capture_locals=True, limit=1)\n'
+             '    return traceback.StackSummary.extract(\n'
              '    a = 1\n'
              '    b = 2\n'
              '    k = 3\n'
-             '    v = 4\n' % (__file__, some_inner.__code__.co_firstlineno + 4)
+             '    v = 4\n' % (__file__, some_inner.__code__.co_firstlineno + 3)
             ], s.format())
 
 class TestTracebackException(unittest.TestCase):

Lib/test/test_tracemalloc.py

@@ -936,7 +936,7 @@ class TestCAPI(unittest.TestCase):
             return None
 
     def track(self, release_gil=False, nframe=1):
-        frames = get_frames(nframe, 2)
+        frames = get_frames(nframe, 1)
         _testcapi.tracemalloc_track(self.domain, self.ptr, self.size,
                                     release_gil)
         return frames

Misc/NEWS.d/next/Core and Builtins/2018-08-15-20-46-49.bpo-12458.ApHbx5.rst

+Tracebacks show now correct line number for subexpressions in multiline
+expressions. Tracebacks show now the line number of the first line for
+multiline expressions instead of the line number of the last subexpression.

Python/compile.c

@@ -4089,10 +4089,6 @@ compiler_comprehension(struct compiler *c, expr_ty e, int type,
     is_async_generator = c->u->u_ste->ste_coroutine;
 
     if (is_async_generator && !is_async_function && type != COMP_GENEXP) {
-        if (e->lineno > c->u->u_lineno) {
-            c->u->u_lineno = e->lineno;
-            c->u->u_lineno_set = 0;
-        }
         compiler_error(c, "asynchronous comprehension outside of "
                           "an asynchronous function");
         goto error_in_scope;
@@ -4430,17 +4426,8 @@ compiler_with(struct compiler *c, stmt_ty s, int pos)
 }
 
 static int
-compiler_visit_expr(struct compiler *c, expr_ty e)
+compiler_visit_expr1(struct compiler *c, expr_ty e)
 {
-    /* If expr e has a different line number than the last expr/stmt,
-       set a new line number for the next instruction.
-    */
-    if (e->lineno > c->u->u_lineno) {
-        c->u->u_lineno = e->lineno;
-        c->u->u_lineno_set = 0;
-    }
-    /* Updating the column offset is always harmless. */
-    c->u->u_col_offset = e->col_offset;
     switch (e->kind) {
     case BoolOp_kind:
         return compiler_boolop(c, e);
@@ -4609,6 +4596,31 @@ compiler_visit_expr(struct compiler *c, expr_ty e)
     return 1;
 }
 
+static int
+compiler_visit_expr(struct compiler *c, expr_ty e)
+{
+    /* If expr e has a different line number than the last expr/stmt,
+       set a new line number for the next instruction.
+    */
+    int old_lineno = c->u->u_lineno;
+    int old_col_offset = c->u->u_col_offset;
+    if (e->lineno != c->u->u_lineno) {
+        c->u->u_lineno = e->lineno;
+        c->u->u_lineno_set = 0;
+    }
+    /* Updating the column offset is always harmless. */
+    c->u->u_col_offset = e->col_offset;
+
+    int res = compiler_visit_expr1(c, e);
+
+    if (old_lineno != c->u->u_lineno) {
+        c->u->u_lineno = old_lineno;
+        c->u->u_lineno_set = 0;
+    }
+    c->u->u_col_offset = old_col_offset;
+    return res;
+}
+
 static int
 compiler_augassign(struct compiler *c, stmt_ty s)
 {