From 9201f46cc8e92231f0f6c92e4d56befbc150f72c Mon Sep 17 00:00:00 2001
From: Damien George <damien.p.george@gmail.com>
Date: Fri, 26 Oct 2018 16:48:07 +1100
Subject: [PATCH] py/compile: Fix case of eager implicit conversion of local to
nonlocal.
This ensures that implicit variables are only converted to implicit
closed-over variables (nonlocals) at the very end of the function scope.
If variables are closed-over when first used (read from, as was done prior
to this commit) then this can be incorrect because the variable may be
assigned to later on in the function which means they are just a plain
local, not closed over.
Fixes issue #4272.
---
py/compile.c | 11 ++++++++++-
py/emitcommon.c | 2 +-
py/scope.c | 8 +++-----
py/scope.h | 2 +-
tests/basics/scope_implicit.py | 31 +++++++++++++++++++++++++++++++
tests/run-tests | 1 +
6 files changed, 47 insertions(+), 8 deletions(-)
create mode 100644 tests/basics/scope_implicit.py
diff --git a/py/compile.c b/py/compile.c
index e90b366e0..e708bde8e 100644
--- a/py/compile.c
+++ b/py/compile.c
@@ -1196,7 +1196,8 @@ STATIC void compile_declare_global(compiler_t *comp, mp_parse_node_t pn, qstr qs
STATIC void compile_declare_nonlocal(compiler_t *comp, mp_parse_node_t pn, qstr qst, bool added, id_info_t *id_info) {
if (added) {
- scope_find_local_and_close_over(comp->scope_cur, id_info, qst);
+ id_info->kind = ID_INFO_KIND_GLOBAL_IMPLICIT;
+ scope_check_to_close_over(comp->scope_cur, id_info);
if (id_info->kind == ID_INFO_KIND_GLOBAL_IMPLICIT) {
compile_syntax_error(comp, pn, "no binding for nonlocal found");
}
@@ -3391,6 +3392,14 @@ mp_raw_code_t *mp_compile_to_raw_code(mp_parse_tree_t *parse_tree, qstr source_f
#endif
} else {
compile_scope(comp, s, MP_PASS_SCOPE);
+
+ // Check if any implicitly declared variables should be closed over
+ for (size_t i = 0; i < s->id_info_len; ++i) {
+ id_info_t *id = &s->id_info[i];
+ if (id->kind == ID_INFO_KIND_GLOBAL_IMPLICIT) {
+ scope_check_to_close_over(s, id);
+ }
+ }
}
// update maximim number of labels needed
diff --git a/py/emitcommon.c b/py/emitcommon.c
index 89cc2c959..149e0b0f1 100644
--- a/py/emitcommon.c
+++ b/py/emitcommon.c
@@ -35,7 +35,7 @@ void mp_emit_common_get_id_for_load(scope_t *scope, qstr qst) {
bool added;
id_info_t *id = scope_find_or_add_id(scope, qst, &added);
if (added) {
- scope_find_local_and_close_over(scope, id, qst);
+ id->kind = ID_INFO_KIND_GLOBAL_IMPLICIT;
}
}
diff --git a/py/scope.c b/py/scope.c
index 1a6ae7b8a..8adb85b80 100644
--- a/py/scope.c
+++ b/py/scope.c
@@ -130,21 +130,19 @@ STATIC void scope_close_over_in_parents(scope_t *scope, qstr qst) {
}
}
-void scope_find_local_and_close_over(scope_t *scope, id_info_t *id, qstr qst) {
+void scope_check_to_close_over(scope_t *scope, id_info_t *id) {
if (scope->parent != NULL) {
for (scope_t *s = scope->parent; s->parent != NULL; s = s->parent) {
- id_info_t *id2 = scope_find(s, qst);
+ id_info_t *id2 = scope_find(s, id->qst);
if (id2 != NULL) {
if (id2->kind == ID_INFO_KIND_LOCAL || id2->kind == ID_INFO_KIND_CELL || id2->kind == ID_INFO_KIND_FREE) {
id->kind = ID_INFO_KIND_FREE;
- scope_close_over_in_parents(scope, qst);
- return;
+ scope_close_over_in_parents(scope, id->qst);
}
break;
}
}
}
- id->kind = ID_INFO_KIND_GLOBAL_IMPLICIT;
}
#endif // MICROPY_ENABLE_COMPILER
diff --git a/py/scope.h b/py/scope.h
index 5e9a0eb7b..d51bb90bb 100644
--- a/py/scope.h
+++ b/py/scope.h
@@ -93,6 +93,6 @@ void scope_free(scope_t *scope);
id_info_t *scope_find_or_add_id(scope_t *scope, qstr qstr, bool *added);
id_info_t *scope_find(scope_t *scope, qstr qstr);
id_info_t *scope_find_global(scope_t *scope, qstr qstr);
-void scope_find_local_and_close_over(scope_t *scope, id_info_t *id, qstr qst);
+void scope_check_to_close_over(scope_t *scope, id_info_t *id);
#endif // MICROPY_INCLUDED_PY_SCOPE_H
diff --git a/tests/basics/scope_implicit.py b/tests/basics/scope_implicit.py
new file mode 100644
index 000000000..aecda7715
--- /dev/null
+++ b/tests/basics/scope_implicit.py
@@ -0,0 +1,31 @@
+# test implicit scoping rules
+
+# implicit nonlocal, with variable defined after closure
+def f():
+ def g():
+ return x # implicit nonlocal
+ x = 3 # variable defined after function that closes over it
+ return g
+print(f()())
+
+# implicit nonlocal at inner level, with variable defined after closure
+def f():
+ def g():
+ def h():
+ return x # implicit nonlocal
+ return h
+ x = 4 # variable defined after function that closes over it
+ return g
+print(f()()())
+
+# local variable which should not be implicitly made nonlocal
+def f():
+ x = 0
+ def g():
+ x # local because next statement assigns to it
+ x = 1
+ g()
+try:
+ f()
+except NameError:
+ print('NameError')
diff --git a/tests/run-tests b/tests/run-tests
index d72ae9dc4..62af90f28 100755
--- a/tests/run-tests
+++ b/tests/run-tests
@@ -358,6 +358,7 @@ def run_tests(pyb, tests, args, base_path="."):
skip_tests.add('basics/del_deref.py') # requires checking for unbound local
skip_tests.add('basics/del_local.py') # requires checking for unbound local
skip_tests.add('basics/exception_chain.py') # raise from is not supported
+ skip_tests.add('basics/scope_implicit.py') # requires checking for unbound local
skip_tests.add('basics/try_finally_return2.py') # requires raise_varargs
skip_tests.add('basics/unboundlocal.py') # requires checking for unbound local
skip_tests.add('misc/features.py') # requires raise_varargs
--
GitLab