From: Brian Warner <warner@allmydata.com>
Date: Wed, 18 Apr 2007 03:29:08 +0000 (-0700)
Subject: encode: fix multi-segment uploads: lambdas inside for loops require special attention... 
X-Git-Tag: tahoe_v0.1.0-0-UNSTABLE~71
X-Git-Url: https://git.rkrishnan.org/components/com_hotproperty/%22doc.html/architecture.txt?a=commitdiff_plain;h=b84d6ed07f8acf2ab25be2b31c64480ac3be66f6;p=tahoe-lafs%2Ftahoe-lafs.git

encode: fix multi-segment uploads: lambdas inside for loops require special attention to make sure you are capturing the *value* of the loop variable and not just the slot it lives in
---

diff --git a/src/allmydata/encode.py b/src/allmydata/encode.py
index 5b74f107..3731999d 100644
--- a/src/allmydata/encode.py
+++ b/src/allmydata/encode.py
@@ -151,7 +151,11 @@ class Encoder(object):
         d = defer.succeed(None)
 
         for i in range(self.num_segments-1):
-            d.addCallback(lambda res: self.do_segment(i))
+            # note to self: this form doesn't work, because lambda only
+            # captures the slot, not the value
+            #d.addCallback(lambda res: self.do_segment(i))
+            # use this form instead:
+            d.addCallback(lambda res, i=i: self.do_segment(i))
         d.addCallback(lambda res: self.do_tail_segment(self.num_segments-1))
 
         d.addCallback(lambda res: self.send_all_subshare_hash_trees())