Integration test highlighting failure while pushing ref deltas in emp…

…ty repo in Mononoke Git

Summary:
We saw this happening in two production repos so we do know that this is a thing. However, my every attempt to reproduce this in an integration test using git client failed miserably. mitrandir77 and I tried to have an integration test with the exact repo contents that were failing in production, but still it worked.

Giving up, I have manually reproduced this by making a CURL request to the Git server on the push endpoint which highlights the problem. This isn't ideal, but its better than nothing and it will help prevent regression in the future.

Differential Revision: D68016834

fbshipit-source-id: 4384d7b22d27d0a8cd4df66cbfdf3d4c711fa7b9

eden/mononoke/tests/integration/mononoke_git_server/test-mononoke-git-server-push-empty-repo-with-deltas.t

@@ -0,0 +1,48 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# This software may be used and distributed according to the terms of the
+# GNU General Public License found in the LICENSE file in the root
+# directory of this source tree.
+
+  $ . "${TEST_FIXTURES}/library.sh"
+  $ REPOTYPE="blob_files"
+  $ setup_common_config $REPOTYPE
+  $ GIT_REPO_ORIGIN="${TESTTMP}/origin/repo-git"
+
+# Start up the Mononoke Git Service
+  $ mononoke_git_service
+
+# Set Mononoke as the Source of Truth
+  $ set_mononoke_as_source_of_truth_for_git
+
+# Setup git repository
+  $ git_client clone -q $MONONOKE_GIT_SERVICE_BASE_URL/$REPONAME.git "$GIT_REPO_ORIGIN"
+  warning: You appear to have cloned an empty repository.
+  $ cd "$GIT_REPO_ORIGIN"
+  $ git init -q
+# File1 should be large enough that Git create a delta for it
+  $ echo "AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1." > file1
+  $ git add .
+  $ git commit -qam "Add file1"  
+  $ git tag -a -m "new tag" first_tag  
+# File1 should be large enough that Git create a delta for it
+  $ echo "AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile1.AddFile2." > file1
+  $ echo "This is file2" > file2.txt
+  $ git add .
+  $ git commit -qam "Modified file1, Added file2"
+  $ git tag -a empty_tag -m ""
+
+Push Git repository to Mononoke
+  $ git pack-objects --all --stdout > packfile
+  $ last_commit=$(git rev-parse HEAD)
+Create the capabilities string
+  $ capabilities="report-status quiet object-format=sha1"
+  $ printf "00980000000000000000000000000000000000000000 $last_commit refs/heads/master_bookmark\0 $capabilities" >> push_data
+  $ echo -n "0000" >> push_data
+  $ cat packfile >> push_data
+Pipe the push data to CURL
+  $ curl -X POST $MONONOKE_GIT_SERVICE_BASE_URL/$REPONAME.git/git-receive-pack -H 'Content-Type: application/x-git-receive-pack-request' -H 'Accept: application/x-git-receive-pack-result' -H 'Accept-Encoding: deflate, gzip, br' -k --cert "$TEST_CERTDIR/client0.crt" --key "$TEST_CERTDIR/client0.key" --data-binary "@push_data" -s -w "\nResponse code: %{http_code}\n"
+  Error in decoding packfile entry: RefDelta { base_id: Sha1(ccce194714ee3fae382fad2f4a67cd6c1a7320cd) }: A delta chain could not be followed as the ref base with id ccce194714ee3fae382fad2f4a67cd6c1a7320cd could not be found
+  Response code: 500
+
+