Fix issue #1689458 by teaching frame_setlineno how to jump to the first line of
a code object.
diff --git a/Lib/test/test_trace.py b/Lib/test/test_trace.py
index a8f5163..f5b8dbf 100644
--- a/Lib/test/test_trace.py
+++ b/Lib/test/test_trace.py
@@ -740,6 +740,27 @@
def test_19_no_jump_without_trace_function(self):
no_jump_without_trace_function()
+ def test_jump_to_firstlineno(self):
+ # This tests that PDB can jump back to the first line in a
+ # file. See issue #1689458. It can only be triggered in a
+ # function call if the function is defined on a single line.
+ code = compile("""
+# Comments don't count.
+output.append(2) # firstlineno is here.
+output.append(3)
+output.append(4)
+""", "<fake module>", "exec")
+ class fake_function:
+ func_code = code
+ jump = (2, 0)
+ tracer = JumpTracer(fake_function)
+ sys.settrace(tracer.trace)
+ namespace = {"output": []}
+ exec code in namespace
+ sys.settrace(None)
+ self.compare_jump_output([2, 3, 2, 3, 4], namespace["output"])
+
+
def test_main():
test_support.run_unittest(
TraceTestCase,
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
index 5e54585..ad31fc5 100644
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -140,20 +140,26 @@
new_lineno);
return -1;
}
-
- /* Find the bytecode offset for the start of the given line, or the
- * first code-owning line after it. */
- PyString_AsStringAndSize(f->f_code->co_lnotab, &lnotab, &lnotab_len);
- addr = 0;
- line = f->f_code->co_firstlineno;
- new_lasti = -1;
- for (offset = 0; offset < lnotab_len; offset += 2) {
- addr += lnotab[offset];
- line += lnotab[offset+1];
- if (line >= new_lineno) {
- new_lasti = addr;
- new_lineno = line;
- break;
+ else if (new_lineno == f->f_code->co_firstlineno) {
+ new_lasti = 0;
+ new_lineno = f->f_code->co_firstlineno;
+ }
+ else {
+ /* Find the bytecode offset for the start of the given
+ * line, or the first code-owning line after it. */
+ PyString_AsStringAndSize(f->f_code->co_lnotab,
+ &lnotab, &lnotab_len);
+ addr = 0;
+ line = f->f_code->co_firstlineno;
+ new_lasti = -1;
+ for (offset = 0; offset < lnotab_len; offset += 2) {
+ addr += lnotab[offset];
+ line += lnotab[offset+1];
+ if (line >= new_lineno) {
+ new_lasti = addr;
+ new_lineno = line;
+ break;
+ }
}
}