From: Fred Drake <fdrake@acm.org>
Date: Tue, 23 Apr 2002 21:21:20 +0000 (+0000)
Subject: Add text about circular references caused by storing frames in local
X-Git-Tag: v2.3c1~5810
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=99d17006c12d2e768a7b8e1c706adf6b4e152140;p=python

Add text about circular references caused by storing frames in local
variables.  This closes SF bug #543148.
---

diff --git a/Doc/lib/libinspect.tex b/Doc/lib/libinspect.tex
index 186fd586b3..a1293f0e96 100644
--- a/Doc/lib/libinspect.tex
+++ b/Doc/lib/libinspect.tex
@@ -321,3 +321,19 @@ which occurs.}
   Return a list of frame records for the stack below the current
   exception.
 \end{funcdesc}
+
+Stackframes stored directly or indirectly in local variables can
+easily cause reference cycles.  Though the cycle detector will catch
+these, destruction of the frames (and local variables) can be made
+deterministic by removing the cycle in a \keyword{finally} clause.
+This is also important if the cycle detector was disabled when Python
+was compiled or using \function{gc.disable()}.  For example:
+
+\begin{verbatim}
+def handle_stackframe_without_leak():
+    frame = inspect.currentframe()
+    try:
+        # do something with the frame
+    finally:
+        del frame
+\end{verbatim}