Severe Regression in Git 1.21.0 -- not receiving any data

[David <courrier@david-kremer.fr>]

# Summary

I was trying to clone the AOSP source tree (Android Open Source Project) 
and I finally was able to formally identify what seems to be a severe 
regression (one that is blocking usage) in the last version of git (2.21.0).

# Steps to reproduce

The AOSP projects recommend to use ubuntu 14.04 as its build platform. 
The git version for this distro is :

```
root@eb57f366840e:/android# git --version
git version 1.9.1
```

In a docker image for this OS, I am able to execute:

```
root@eb57f366840e:~# git clone 
https://android.googlesource.com/platform/manifest
Cloning into 'manifest'...
remote: Sending approximately 39.94 MiB ...
remote: Counting objects: 852, done
remote: Finding sources: 100% (27/27)
remote: Total 16017 (delta 4968), reused 16017 (delta 4968)
Receiving objects: 100% (16017/16017), 39.65 MiB | 9.04 MiB/s, done.
Resolving deltas: 100% (4968/4968), done.
Checking connectivity... done.
```

Now, on my local Archlinux Box, the git version is 2.21.0 (latest).

The same command:

```

git clone https://android.googlesource.com/platform/manifest
```

Is launching a single thread that uses 100% of one CPU core FOREVER, 
until a timeout arises after like 40 minutes (the remote hung up 
unexpectedly). Someone on the #git channel (irc.freenode.net) was able 
to reproduce the exact same behaviour.

I must add that this of course arises only with the repo I mention in 
this email (github repositories are just fine). So probably a mismatch 
in protocol between git server/client ? Anyways, I'm far from having the 
skills to fix that thing.

I hope this report is useful, and in any case, I would like to know 
about the possible outcomes of this report.

I would be actually very surprised if someone did not notice that 
before, given that the latest git version is from february, but I can 
try anyway :)

Cheers,

David