git-ftp not working on commits that are deleting files (error message "fatal: Could not upload files., exiting...")

Bug / Enhancement / Question ?

Trying to run git ftp init (on a local Git repository where an old version of git ftp had already been used a couple of years ago, but this time uploading to a new sftp server - i.e. which doesn't have the .git-ftp.log file)

Immediately after displaying Uploading ..., it says : fatal: Could not upload files., exiting...

Trying to switch to another git branch, and reducing the number of files to a reasonable amount (200 files buffered for upload instead of 6672) didn't help to resolve the problem : still saying fatal: Could not upload files., exiting...

Running git ftp -vv init for verbose output, it says:

[…]
Jeu 20 avr 2023 13:27:02 CEST: Uploading ...
*   Trying 195.***.***.90:50027...
* Connected to 195.***.***.90 (195.***.***.90) port 50027 (#0)
* Found host 195.***.***.90 in /Users/pierre/.ssh/known_hosts
* Set "rsa-sha2-256,rsa-sha2-512,ssh-rsa" as SSH hostkey type
* SSH MD5 public key: NULL                                                                                                          
* SSH SHA256 public key: NULL
* SSH host check: 0, key: AAAAB3NzaC1y.....sKlkLyOKeK4lVHw==
* SSH authentication methods available: publickey,gssapi-keyex,gssapi-with-mic,password                                             
* Using SSH private key file ''
* SSH public key authentication failed: Unable to extract public key from private key file: Unable to open private key file
* Initialized password authentication
* Authentication complete
} [595 bytes data]                                                                                                                  
* We are completely uploaded and fine
############################################################################################################################## 100.0%* Connection #0 to host 195.***.***.90 left intact

* Found bundle for host: 0x7fee56422230 [serially]
* Re-using existing connection #0 with host 195.***.***.90
} [17497 bytes data]
* We are completely uploaded and fine
############################################################################################################################## 100.0%* Connection #0 to host 195.***.***.90 left intact

* Found bundle for host: 0x7fee56422230 [serially]
* Re-using existing connection #0 with host 195.***.***.90
} [30000 bytes data]
* We are completely uploaded and fine
############################################################################################################################## 100.0%* Connection #0 to host 195.***.***.90 left intact

* Found bundle for host: 0x7fee56422230 [serially]
* Re-using existing connection #0 with host 195.***.***.90
} [30000 bytes data]
* We are completely uploaded and fine
############################################################################################################################## 100.0%* Connection #0 to host 195.***.***.90 left intact

* Found bundle for host: 0x7fee56422230 [serially]
* Re-using existing connection #0 with host 195.***.***.90
} [4012 bytes data]
* We are completely uploaded and fine
############################################################################################################################## 100.0%* Connection #0 to host 195.***.***.90 left intact

* Found bundle for host: 0x7fee56422230 [serially]
* Re-using existing connection #0 with host 195.***.***.90
} [2326 bytes data]
* We are completely uploaded and fine
############################################################################################################################## 100.0%* Connection #0 to host 195.***.***.90 left intact

* Found bundle for host: 0x7fee56422230 [serially]
* Re-using existing connection #0 with host 195.***.***.90
} [2326 bytes data]
* We are completely uploaded and fine
############################################################################################################################## 100.0%* Connection #0 to host 195.***.***.90 left intact

curl: (3) URL using bad/illegal format or missing URL
Jeu 20 avr 2023 13:27:03 CEST: fatal: Could not upload files., exiting...

=> it would be nice to have more details about the bad/illegal format or missing URL (it's a pity that the git ftp -vv doesn't display the curl commands with their parameters)

Also tried with git ftp init --insecure but it's the same.

So I manually uploaded all the 200 files from this git branch, and then ran git ftp catchup, then switched back to my master git branch containing 6000+ files to be uploaded, and ran git ftp push: it displayed Uploading ... then it took several minutes to upload the files, and after a while, it stops unexpectedly, saying fatal: Could not upload files., exiting...

When running git ftp push -vv I get:

[…]
* Found bundle for host: 0x7f979899f880 [serially]
* Re-using existing connection #0 with host 195.***.***.90
} [598 bytes data]
* We are completely uploaded and fine
################################################################################################################################################################################################ 100.0%* Connection #0 to host 195.***.***.90 left intact

* Found bundle for host: 0x7f979899f880 [serially]
* Re-using existing connection #0 with host 195.***.***.90
} [1573 bytes data]
* We are completely uploaded and fine
################################################################################################################################################################################################ 100.0%* Connection #0 to host 195.***.***.90 left intact

* Found bundle for host: 0x7f979899f880 [serially]
* Re-using existing connection #0 with host 195.***.***.90
} [1096 bytes data]
* We are completely uploaded and fine
################################################################################################################################################################################################ 100.0%* Connection #0 to host 195.***.***.90 left intact

* Found bundle for host: 0x7f979899f880 [serially]
* Re-using existing connection #0 with host 195.***.***.90
} [937 bytes data]
* We are completely uploaded and fine
################################################################################################################################################################################################ 100.0%* Connection #0 to host 195.***.***.90 left intact

* Found bundle for host: 0x7f979899f880 [serially]
* Re-using existing connection #0 with host 195.***.***.90
} [415 bytes data]
* We are completely uploaded and fine
################################################################################################################################################################################################ 100.0%* Connection #0 to host 195.***.***.90 left intact

* Found bundle for host: 0x7f979899f880 [serially]
* Re-using existing connection #0 with host 195.***.***.90
} [5954 bytes data]
* We are completely uploaded and fine
################################################################################################################################################################################################ 100.0%* Connection #0 to host 195.***.***.90 left intact

curl: (3) URL using bad/illegal format or missing URL
Jeu 20 avr 2023 14:59:29 CEST: fatal: Could not upload files., exiting...

When connecting to the sftp server, I can see that it has successfully uploaded some of the files, but not all the files.

Environment

/bin/bash
Darwin BCL-MacBookPro-2.local 19.6.0 Darwin Kernel Version 19.6.0: Tue Jun 21 21:18:39 PDT 2022; root:xnu-6153.141.66~1/RELEASE_X86_64 x86_64
git-ftp version 1.6.0

Notes:

• git-ftp has been installed through brew install git-ftp ; which in turns required dependency zstd ; which I had to install without support of LibLZMA because I'm running under macOS Catalina 10.15.7 (is this a problem ? Does git-ftp requires LibLZMA ??)
• curl --version says :

Release-Date: 2023-03-20
Protocols: dict file ftp ftps gopher gophers http https imap imaps ldap ldaps mqtt pop3 pop3s rtmp rtsp scp sftp smb smbs smtp smtps telnet tftp
Features: alt-svc AsynchDNS brotli GSS-API HSTS HTTP2 HTTPS-proxy IDN IPv6 Kerberos Largefile libz MultiSSL NTLM NTLM_WB SPNEGO SSL threadsafe TLS-SRP UnixSockets zstd

No source file or test is named. Start by reproducing the failure with git ftp init and git ftp push on commits containing deletions, using -vv to inspect the curl output. Done means the offending URL or deleted path is identified and the command reports a useful error while completing the valid uploads.