stream-clone: add a test that highlight crash on revlog splitting

This has been a long running problem, we should have a tests for it.

tests/test-clone-stream-revlog-split.t

@@ -0,0 +1,150 b''
+Test stream cloning while a revlog split happens
+------------------------------------------------
+
+#testcases stream-bundle2-v2 stream-bundle2-v3
+
+#if stream-bundle2-v3
+  $ cat << EOF >> $HGRCPATH
+  > [experimental]
+  > stream-v3 = yes
+  > EOF
+#endif
+
+setup a repository for tests
+----------------------------
+
+  $ cat >> $HGRCPATH << EOF
+  > [format]
+  > # skip compression to make it easy to trigger a split
+  > revlog-compression=none
+  > EOF
+
+  $ hg init server
+  $ cd server
+  $ file="some-file"
+  $ printf '%20d' '1' > $file
+  $ hg commit -Aqma
+  $ printf '%1024d' '1' > $file
+  $ hg commit -Aqmb
+  $ printf '%20d' '1' > $file
+  $ hg commit -Aqmc
+
+check the revlog is inline
+
+  $ f -s .hg/store/data/some-file*
+  .hg/store/data/some-file.i: size=1259
+  $ hg debug-revlog-index some-file
+     rev linkrev       nodeid    p1-nodeid    p2-nodeid
+       0       0 ed70cecbc103 000000000000 000000000000
+       1       1 7241018db64c ed70cecbc103 000000000000
+       2       2 fa1120531cc1 7241018db64c 000000000000
+  $ cd ..
+
+setup synchronisation file
+
+  $ HG_TEST_STREAM_WALKED_FILE_1="$TESTTMP/sync_file_walked_1"
+  $ export HG_TEST_STREAM_WALKED_FILE_1
+  $ HG_TEST_STREAM_WALKED_FILE_2="$TESTTMP/sync_file_walked_2"
+  $ export HG_TEST_STREAM_WALKED_FILE_2
+  $ HG_TEST_STREAM_WALKED_FILE_3="$TESTTMP/sync_file_walked_3"
+  $ export HG_TEST_STREAM_WALKED_FILE_3
+
+
+Test stream-clone raced by a revlog-split
+=========================================
+
+Test stream-clone where the file is split right after the lock section is done
+
+Start the server
+
+  $ hg serve -R server \
+  >   -p $HGPORT1 -d --error errors.log --pid-file=hg.pid \
+  >   --config extensions.stream_steps="$RUNTESTDIR/testlib/ext-stream-clone-steps.py"
+  $ cat hg.pid >> $DAEMON_PIDS
+
+Start a client doing a streaming clone
+
+  $ (hg clone -q --stream -U http://localhost:$HGPORT1 clone-while-split > client.log 2>&1; touch "$HG_TEST_STREAM_WALKED_FILE_3") &
+
+Wait for the server to be done collecting data
+
+  $ $RUNTESTDIR/testlib/wait-on-file 10 $HG_TEST_STREAM_WALKED_FILE_1
+
+trigger a split
+
+  $ dd if=/dev/zero of=server/$file bs=1k count=128 > /dev/null 2>&1
+  $ hg -R server ci -m "triggering a split" --config ui.timeout.warn=-1
+
+unlock the stream generation
+
+  $ touch $HG_TEST_STREAM_WALKED_FILE_2
+
+wait for the client to be done cloning.
+
+  $ $RUNTESTDIR/testlib/wait-on-file 10 $HG_TEST_STREAM_WALKED_FILE_3
+
+Check everything is fine
+
+  $ cat client.log
+  remote: abort: unexpected error: clone could only read 256 bytes from data/some-file.i, but expected 1259 bytes (known-bad-output !)
+  abort: pull failed on remote (known-bad-output !)
+  $ tail -2 errors.log
+  mercurial.error.Abort: clone could only read 256 bytes from data/some-file.i, but expected 1259 bytes (known-bad-output !)
+   (known-bad-output !)
+  $ hg -R clone-while-split verify
+  checking changesets (missing-correct-output !)
+  checking manifests (missing-correct-output !)
+  crosschecking files in changesets and manifests (missing-correct-output !)
+  checking files (missing-correct-output !)
+  checking dirstate (missing-correct-output !)
+  checked 3 changesets with 3 changes to 1 files (missing-correct-output !)
+  abort: repository clone-while-split not found (known-bad-output !)
+  [255]
+  $ hg -R clone-while-split tip
+  changeset:   2:dbd9854c38a6 (missing-correct-output !)
+  tag:         tip (missing-correct-output !)
+  user:        test (missing-correct-output !)
+  date:        Thu Jan 01 00:00:00 1970 +0000 (missing-correct-output !)
+  summary:     c (missing-correct-output !)
+   (missing-correct-output !)
+  abort: repository clone-while-split not found (known-bad-output !)
+  [255]
+  $ hg -R clone-while-split debug-revlog-index some-file
+     rev linkrev       nodeid    p1-nodeid    p2-nodeid (missing-correct-output !)
+       0       0 ed70cecbc103 000000000000 000000000000 (missing-correct-output !)
+       1       1 7241018db64c ed70cecbc103 000000000000 (missing-correct-output !)
+       2       2 fa1120531cc1 7241018db64c 000000000000 (missing-correct-output !)
+  abort: repository clone-while-split not found (known-bad-output !)
+  [255]
+
+subsequent pull work
+
+  $ hg -R clone-while-split pull
+  pulling from http://localhost:$HGPORT1/ (missing-correct-output !)
+  searching for changes (missing-correct-output !)
+  adding changesets (missing-correct-output !)
+  adding manifests (missing-correct-output !)
+  adding file changes (missing-correct-output !)
+  added 1 changesets with 1 changes to 1 files (missing-correct-output !)
+  new changesets df05c6cb1406 (missing-correct-output !)
+  (run 'hg update' to get a working copy) (missing-correct-output !)
+  abort: repository clone-while-split not found (known-bad-output !)
+  [255]
+
+  $ hg -R clone-while-split debug-revlog-index some-file
+     rev linkrev       nodeid    p1-nodeid    p2-nodeid (missing-correct-output !)
+       0       0 ed70cecbc103 000000000000 000000000000 (missing-correct-output !)
+       1       1 7241018db64c ed70cecbc103 000000000000 (missing-correct-output !)
+       2       2 fa1120531cc1 7241018db64c 000000000000 (missing-correct-output !)
+       3       3 a631378adaa3 fa1120531cc1 000000000000 (missing-correct-output !)
+  abort: repository clone-while-split not found (known-bad-output !)
+  [255]
+  $ hg -R clone-while-split verify
+  checking changesets (missing-correct-output !)
+  checking manifests (missing-correct-output !)
+  crosschecking files in changesets and manifests (missing-correct-output !)
+  checking files (missing-correct-output !)
+  checking dirstate (missing-correct-output !)
+  checked 4 changesets with 4 changes to 1 files (missing-correct-output !)
+  abort: repository clone-while-split not found (known-bad-output !)
+  [255]