Protocol v2: The wrong --shallow-since time format causes git to wait indefinitely

Recently, when I tested my Git Over HTTP server, I found a bug in Git. When we used git -c protocol.version=2 clone --shallow-since , if the time format is wrong, it will cause git to wait indefinitely.

Github supports Wire Protocol to reproduce, Gitlab does not support it and does not reproduce it.

The commands that can be retried are as follows:

# time format wrong
git -c protocol.version=2 clone https://github.com/git/git.git --shallow-since=20151012
# trace
GIT_TRACE=1 GIT_CURL_VERBOSE=1 GIT_TRACE_PACKET=2 git -c protocol.version=2 clone https://github.com/git/git.git --shallow-since=20151012

We can see that the server closes the HTTP connection after sending the `shallow-info\n` message, and git-remote-http(s) is still waiting.

$ git --version --build-options
git version 2.24.0
cpu: x86_64
no commit associated with this build
sizeof-long: 8
sizeof-size_t: 8

When the time format is correct, the clone is successful, so this is followed by the shallow-list：

GIT_TRACE=1 GIT_CURL_VERBOSE=1 GIT_TRACE_PACKET=2 git -c protocol.version=2 clone https://github.com/git/git.git --shallow-since=2015-10-12

Github Issues: https://github.com/gitgitgadget/git/issues/457