Fix SF bug [ #450245 ] Error in parsing future stmts
Check return value from future_parse() in for loop for file_input to
accomodate multiple future statements on separate lines.
Add several comments explaining how the code works.
Remove out-dated XXX comment.
diff --git a/Python/future.c b/Python/future.c
index 6b1c0c5..563bbdf 100644
--- a/Python/future.c
+++ b/Python/future.c
@@ -8,6 +8,9 @@
#define UNDEFINED_FUTURE_FEATURE "future feature %.100s is not defined"
#define FUTURE_IMPORT_STAR "future statement does not support import *"
+/* FUTURE_POSSIBLE() is provided to accomodate doc strings, which is
+ the only statement that can occur before a future statement.
+*/
#define FUTURE_POSSIBLE(FF) ((FF)->ff_last_lineno == -1)
static int
@@ -57,7 +60,6 @@
"from __future__ imports must occur at the "
"beginning of the file");
PyErr_SyntaxLocation(filename, n->n_lineno);
- /* XXX set filename and lineno */
}
/* Relevant portions of the grammar:
@@ -75,7 +77,12 @@
dotted_name: NAME ('.' NAME)*
*/
-/* future_parse() return values:
+/* future_parse() finds future statements at the beginnning of a
+ module. The function calls itself recursively, rather than
+ factoring out logic for different kinds of statements into
+ different routines.
+
+ Return values:
-1 indicates an error occurred, e.g. unknown feature name
0 indicates no feature was found
1 indicates a feature was found
@@ -97,11 +104,19 @@
return 0;
case file_input:
+ /* Check each statement in the file, starting with the
+ first, and continuing until the first statement
+ that isn't a future statement.
+ */
for (i = 0; i < NCH(n); i++) {
node *ch = CHILD(n, i);
if (TYPE(ch) == stmt) {
r = future_parse(ff, ch, filename);
- if (!FUTURE_POSSIBLE(ff))
+ /* Need to check both conditions below
+ to accomodate doc strings, which
+ causes r < 0.
+ */
+ if (r < 1 && !FUTURE_POSSIBLE(ff))
return r;
}
}