gh-98811: use full source location to simplify __future__ imports error checking. This also fixes an incorrect error offset. (GH-98812)

1 files changed, 32 insertions, 30 deletions

diff --git a/Python/compile.c b/Python/compile.c
index 7797291..f892478 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -125,18 +125,23 @@
         (c->c_flags->cf_flags & PyCF_ALLOW_TOP_LEVEL_AWAIT) \
         && (c->u->u_ste->ste_type == ModuleBlock))
 
-typedef struct location_ {
-    int lineno;
-    int end_lineno;
-    int col_offset;
-    int end_col_offset;
-} location;
+typedef _PyCompilerSrcLocation location;
 
 #define LOCATION(LNO, END_LNO, COL, END_COL) \
     ((const location){(LNO), (END_LNO), (COL), (END_COL)})
 
 static location NO_LOCATION = {-1, -1, -1, -1};
 
+/* Return true if loc1 starts after loc2 ends. */
+static inline bool
+location_is_after(location loc1, location loc2) {
+    return (loc1.lineno > loc2.end_lineno) ||
+            ((loc1.lineno == loc2.end_lineno) &&
+             (loc1.col_offset > loc2.end_col_offset));
+}
+
+#define LOC(x) SRC_LOCATION_FROM_AST(x)
+
 typedef struct jump_target_label_ {
     int id;
 } jump_target_label;
@@ -1012,11 +1017,6 @@ basicblock_next_instr(basicblock *b)
 // Artificial instructions
 #define UNSET_LOC(c)
 
-#define LOC(x) LOCATION((x)->lineno,          \
-                        (x)->end_lineno,      \
-                        (x)->col_offset,      \
-                        (x)->end_col_offset)
-
 
 /* Return the stack effect of opcode with argument oparg.
 
@@ -3911,59 +3911,61 @@ compiler_import(struct compiler *c, stmt_ty s)
 static int
 compiler_from_import(struct compiler *c, stmt_ty s)
 {
-    location loc = LOC(s);
-    Py_ssize_t i, n = asdl_seq_LEN(s->v.ImportFrom.names);
-    PyObject *names;
+    Py_ssize_t n = asdl_seq_LEN(s->v.ImportFrom.names);
 
-    ADDOP_LOAD_CONST_NEW(c, loc, PyLong_FromLong(s->v.ImportFrom.level));
+    ADDOP_LOAD_CONST_NEW(c, LOC(s), PyLong_FromLong(s->v.ImportFrom.level));
 
-    names = PyTuple_New(n);
-    if (!names)
+    PyObject *names = PyTuple_New(n);
+    if (!names) {
         return 0;
+    }
 
     /* build up the names */
-    for (i = 0; i < n; i++) {
+    for (Py_ssize_t i = 0; i < n; i++) {
         alias_ty alias = (alias_ty)asdl_seq_GET(s->v.ImportFrom.names, i);
         Py_INCREF(alias->name);
         PyTuple_SET_ITEM(names, i, alias->name);
     }
 
-    if (s->lineno > c->c_future->ff_lineno && s->v.ImportFrom.module &&
-        _PyUnicode_EqualToASCIIString(s->v.ImportFrom.module, "__future__")) {
+    if (location_is_after(LOC(s), c->c_future->ff_location) &&
+        s->v.ImportFrom.module &&
+        _PyUnicode_EqualToASCIIString(s->v.ImportFrom.module, "__future__"))
+    {
         Py_DECREF(names);
-        return compiler_error(c, loc, "from __future__ imports must occur "
+        return compiler_error(c, LOC(s), "from __future__ imports must occur "
                               "at the beginning of the file");
     }
-    ADDOP_LOAD_CONST_NEW(c, loc, names);
+    ADDOP_LOAD_CONST_NEW(c, LOC(s), names);
 
     if (s->v.ImportFrom.module) {
-        ADDOP_NAME(c, loc, IMPORT_NAME, s->v.ImportFrom.module, names);
+        ADDOP_NAME(c, LOC(s), IMPORT_NAME, s->v.ImportFrom.module, names);
     }
     else {
         _Py_DECLARE_STR(empty, "");
-        ADDOP_NAME(c, loc, IMPORT_NAME, &_Py_STR(empty), names);
+        ADDOP_NAME(c, LOC(s), IMPORT_NAME, &_Py_STR(empty), names);
     }
-    for (i = 0; i < n; i++) {
+    for (Py_ssize_t i = 0; i < n; i++) {
         alias_ty alias = (alias_ty)asdl_seq_GET(s->v.ImportFrom.names, i);
         identifier store_name;
 
         if (i == 0 && PyUnicode_READ_CHAR(alias->name, 0) == '*') {
             assert(n == 1);
-            ADDOP(c, loc, IMPORT_STAR);
+            ADDOP(c, LOC(s), IMPORT_STAR);
             return 1;
         }
 
-        ADDOP_NAME(c, loc, IMPORT_FROM, alias->name, names);
+        ADDOP_NAME(c, LOC(s), IMPORT_FROM, alias->name, names);
         store_name = alias->name;
-        if (alias->asname)
+        if (alias->asname) {
             store_name = alias->asname;
+        }
 
-        if (!compiler_nameop(c, loc, store_name, Store)) {
+        if (!compiler_nameop(c, LOC(s), store_name, Store)) {
             return 0;
         }
     }
     /* remove imported module */
-    ADDOP(c, loc, POP_TOP);
+    ADDOP(c, LOC(s), POP_TOP);
     return 1;
 }