Issue #15812: inspect.getframeinfo() now correctly shows the first line of a context

Patch by Sam Breese.

Lib/inspect.py

@@ -1416,7 +1416,7 @@ def getframeinfo(frame, context=1):
         except OSError:
             lines = index = None
         else:
-            start = max(start, 1)
+            start = max(start, 0)
             start = max(0, min(start, len(lines) - context))
             lines = lines[start:start+context]
             index = lineno - 1 - start

Lib/test/test_inspect.py

@@ -391,6 +391,11 @@ class TestRetrievingSourceCode(GetSourceBase):
         # Check filename override
         self.assertEqual(inspect.getmodule(None, modfile), mod)
 
+    def test_getframeinfo_get_first_line(self):
+        frame_info = inspect.getframeinfo(self.fodderModule.fr, 50)
+        self.assertEqual(frame_info.code_context[0], "# line 1\n")
+        self.assertEqual(frame_info.code_context[1], "'A module docstring.'\n")
+
     def test_getsource(self):
         self.assertSourceEqual(git.abuse, 29, 39)
         self.assertSourceEqual(mod.StupidGit, 21, 51)

Misc/NEWS

@@ -140,6 +140,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #15812: inspect.getframeinfo() now correctly shows the first line of
+  a context.  Patch by Sam Breese.
+
 - Issue #29094: Offsets in a ZIP file created with extern file object and modes
   "w" and "x" now are relative to the start of the file.