# HG changeset patch
# User Gregory Szorc <gregory.szorc@gmail.com>
# Date 2016-11-26 17:07:11
# Node ID 98d7636c472966eb45f17972ed4f422b05946cb2
# Parent  3899c358b45a108f01f5d3506c3cfe579f6dddfd

util: limit output chunk size in zlib decompression

This is essentially a port of 65bd4b8e48bd, which was inadvertently
dropped by 8cd7d0fefd30.

diff --git a/mercurial/util.py b/mercurial/util.py
--- a/mercurial/util.py
+++ b/mercurial/util.py
@@ -3124,7 +3124,10 @@ class _zlibengine(compressionengine):
         def gen():
             d = zlib.decompressobj()
             for chunk in filechunkiter(fh):
-                yield d.decompress(chunk)
+                while chunk:
+                    # Limit output size to limit memory.
+                    yield d.decompress(chunk, 2 ** 18)
+                    chunk = d.unconsumed_tail
 
         return chunkbuffer(gen())