exchange: don't send stream data when server.uncompressed is set

exchange: don't send stream data when server.uncompressed is set

Previously, bundle2 stream support would send out data even though
the streaming clone feature was disabled. This commit changes
the part handler to respect the server config.

Differential Revision: https://phab.mercurial-scm.org/D1930

--- a/mercurial/exchange.py	Mon Jan 22 12:21:15 2018 -0800
+++ b/mercurial/exchange.py	Mon Jan 22 12:22:01 2018 -0800
@@ -1773,6 +1773,13 @@
     if not kwargs.get('stream', False):
         return
 
+    if not streamclone.allowservergeneration(repo):
+        raise error.Abort(_('stream data requested but server does not allow '
+                            'this feature'),
+                          hint=_('well-behaved clients should not be '
+                                 'requesting stream data from servers not '
+                                 'advertising it; the client may be buggy'))
+
     # Stream clones don't compress well. And compression undermines a
     # goal of stream clones, which is to be fast. Communicate the desire
     # to avoid compression to consumers of the bundle.

--- a/tests/test-clone-uncompressed.t	Mon Jan 22 12:21:15 2018 -0800
+++ b/tests/test-clone-uncompressed.t	Mon Jan 22 12:22:01 2018 -0800
@@ -87,14 +87,14 @@
   
 
   $ f --size body --hexdump --bytes 100
-  body: size=112318
+  body: size=232
   0000: 04 6e 6f 6e 65 48 47 32 30 00 00 00 00 00 00 00 |.noneHG20.......|
-  0010: 68 07 53 54 52 45 41 4d 32 00 00 00 00 03 00 09 |h.STREAM2.......|
-  0020: 05 09 04 0c 2d 62 79 74 65 63 6f 75 6e 74 39 38 |....-bytecount98|
-  0030: 37 35 38 66 69 6c 65 63 6f 75 6e 74 31 30 33 30 |758filecount1030|
-  0040: 72 65 71 75 69 72 65 6d 65 6e 74 73 64 6f 74 65 |requirementsdote|
-  0050: 6e 63 6f 64 65 20 66 6e 63 61 63 68 65 20 67 65 |ncode fncache ge|
-  0060: 6e 65 72 61                                     |nera|
+  0010: cf 0b 45 52 52 4f 52 3a 41 42 4f 52 54 00 00 00 |..ERROR:ABORT...|
+  0020: 00 01 01 07 3c 04 72 6d 65 73 73 61 67 65 73 74 |....<.rmessagest|
+  0030: 72 65 61 6d 20 64 61 74 61 20 72 65 71 75 65 73 |ream data reques|
+  0040: 74 65 64 20 62 75 74 20 73 65 72 76 65 72 20 64 |ted but server d|
+  0050: 6f 65 73 20 6e 6f 74 20 61 6c 6c 6f 77 20 74 68 |oes not allow th|
+  0060: 69 73 20 66                                     |is f|
 
 #endif
 #if stream-bundle2
@@ -152,14 +152,14 @@
   
 
   $ f --size body --hexdump --bytes 100
-  body: size=112318
+  body: size=232
   0000: 04 6e 6f 6e 65 48 47 32 30 00 00 00 00 00 00 00 |.noneHG20.......|
-  0010: 68 07 53 54 52 45 41 4d 32 00 00 00 00 03 00 09 |h.STREAM2.......|
-  0020: 05 09 04 0c 2d 62 79 74 65 63 6f 75 6e 74 39 38 |....-bytecount98|
-  0030: 37 35 38 66 69 6c 65 63 6f 75 6e 74 31 30 33 30 |758filecount1030|
-  0040: 72 65 71 75 69 72 65 6d 65 6e 74 73 64 6f 74 65 |requirementsdote|
-  0050: 6e 63 6f 64 65 20 66 6e 63 61 63 68 65 20 67 65 |ncode fncache ge|
-  0060: 6e 65 72 61                                     |nera|
+  0010: cf 0b 45 52 52 4f 52 3a 41 42 4f 52 54 00 00 00 |..ERROR:ABORT...|
+  0020: 00 01 01 07 3c 04 72 6d 65 73 73 61 67 65 73 74 |....<.rmessagest|
+  0030: 72 65 61 6d 20 64 61 74 61 20 72 65 71 75 65 73 |ream data reques|
+  0040: 74 65 64 20 62 75 74 20 73 65 72 76 65 72 20 64 |ted but server d|
+  0050: 6f 65 73 20 6e 6f 74 20 61 6c 6c 6f 77 20 74 68 |oes not allow th|
+  0060: 69 73 20 66                                     |is f|
 
 #endif