macOS: croc always creates a folder "~" when receiving files

[jonasjelonek]

As the title says, croc behaves somewhat strange on macOS. I usually transfer files/folders between Linux and Windows machine, and my Mac using croc. When I send something from my Mac to Windows/Linux everything works as expected. However, when sending files from Windows/Linux to my Mac, croc always creates a folder called "~" in the same folder where the received files/folders are stored and the "~" folder doesn't have any content.

I'm using latest macOS 15.1.1 and croc 10.2.1 on macOS.

What I've observed so far:

• only occurs when sending files from another system to macOS
• doesn't depend on what is sent (single/multiple files or folders, file type/extension, size, etc.)
• debug output of croc has no hint on creation of that "~" folder

[debug] 11:59:43 cli.go:215: debug mode on
[debug] 11:59:43 cli.go:219: public IP address: 46.142.11.245
Enter receive code: 1777-import-volcano-claudia
connecting...[debug]    11:59:50 croc.go:884: attempt to discover peers
[debug] 11:59:51 croc.go:950: discoveries: []
[debug] 11:59:51 croc.go:951: establishing connection
[debug] 11:59:51 croc.go:967: got host '2a01:4f8:1c1c:7804::1' and port '9009'
[debug] 11:59:51 croc.go:969: trying connection to [2a01:4f8:1c1c:7804::1]:9009
[debug] 11:59:51 comm.go:78: dialing to [2a01:4f8:1c1c:7804::1]:9009 with timelimit 200ms
[debug] 11:59:51 comm.go:87: connected to '[2a01:4f8:1c1c:7804::1]:9009'
[debug] 11:59:51 tcp.go:523: strong key: 685893b3260e6c69767d363c7e8cd260569abe81d045ab8a79808d8c86efe5ff
[debug] 11:59:51 tcp.go:537: sending password
[debug] 11:59:51 tcp.go:548: waiting for first ok
[debug] 11:59:51 tcp.go:566: sending room; 448a7ec0de8631886809d5f502d85e287691fb1bbf1284f75bd811fe3c349652
[debug] 11:59:51 tcp.go:577: waiting for room confirmation
[debug] 11:59:51 tcp.go:593: all set
[debug] 11:59:51 croc.go:982: receiver connection established: &{connection:0x140000b6080}
[debug] 11:59:51 croc.go:983: banner: 9010,9011,9012,9013,9014,9015,9016,9017
[debug] 11:59:51 croc.go:1027: dataMessage kA: 6fe521a6b24fbb40a520a18ccc14222dd3373e18a8ce10a8c709fb85f39c33b4
[debug] 11:59:51 croc.go:1034: sending ips?
[debug] 11:59:51 croc.go:1046: ips data: ["9009","169.254.156.222","10.9.4.15","169.254.7.206","192.168.42.127"]
[debug] 11:59:51 croc.go:1058: ipv4Add4: 169.254.156.222, ipv4Net: 169.254.156.0/24, err: <nil>
[debug] 11:59:51 croc.go:1063: localIP: 192.168.1.100, localIPparsed: 192.168.1.100
[debug] 11:59:51 croc.go:1063: localIP: 192.168.42.42, localIPparsed: 192.168.42.42
[debug] 11:59:51 croc.go:1071: 169.254.156.222 is not a local IP, skipping
[debug] 11:59:51 croc.go:1058: ipv4Add4: 10.9.4.15, ipv4Net: 10.9.4.0/24, err: <nil>
[debug] 11:59:51 croc.go:1063: localIP: 192.168.1.100, localIPparsed: 192.168.1.100
[debug] 11:59:51 croc.go:1063: localIP: 192.168.42.42, localIPparsed: 192.168.42.42
[debug] 11:59:51 croc.go:1071: 10.9.4.15 is not a local IP, skipping
[debug] 11:59:51 croc.go:1058: ipv4Add4: 169.254.7.206, ipv4Net: 169.254.7.0/24, err: <nil>
[debug] 11:59:51 croc.go:1063: localIP: 192.168.1.100, localIPparsed: 192.168.1.100
[debug] 11:59:51 croc.go:1063: localIP: 192.168.42.42, localIPparsed: 192.168.42.42
[debug] 11:59:51 croc.go:1071: 169.254.7.206 is not a local IP, skipping
[debug] 11:59:51 croc.go:1058: ipv4Add4: 192.168.42.127, ipv4Net: 192.168.42.0/24, err: <nil>
[debug] 11:59:51 croc.go:1063: localIP: 192.168.1.100, localIPparsed: 192.168.1.100
[debug] 11:59:51 croc.go:1063: localIP: 192.168.42.42, localIPparsed: 192.168.42.42
[debug] 11:59:51 croc.go:1066: ip: 192.168.42.127 is a local IP
[debug] 11:59:51 comm.go:78: dialing to 192.168.42.127:9009 with timelimit 500ms
[debug] 11:59:51 comm.go:87: connected to '192.168.42.127:9009'
[debug] 11:59:51 tcp.go:523: strong key: 21da886dfde8682f48f8b0128feb4aa7ee3549eba984d05a7c86260f481333a6
[debug] 11:59:51 tcp.go:537: sending password
[debug] 11:59:51 tcp.go:548: waiting for first ok
[debug] 11:59:51 tcp.go:566: sending room; 448a7ec0de8631886809d5f502d85e287691fb1bbf1284f75bd811fe3c349652
[debug] 11:59:51 tcp.go:577: waiting for room confirmation
[debug] 11:59:51 tcp.go:593: all set
[debug] 11:59:51 croc.go:1082: local connection established to 192.168.42.127:9009
[debug] 11:59:51 croc.go:1083: banner: 9010,9011,9012,9013
[debug] 11:59:51 croc.go:1104: exchanged header message
securing channel...[debug]      11:59:51 croc.go:1122: ready
[debug] 11:59:51 message.go:61: writing pake message (unencrypted)
[debug] 11:59:51 message.go:80: read pake message (unencrypted)
[debug] 11:59:51 croc.go:1387: received pake payload
[debug] 11:59:51 croc.go:1434: generated key = a0aa9aa7da5a7a839c2006db1d4fa4bfe70f76f18a3419979b1bfda47fc88912 with salt da06610663db7f8f
[debug] 11:59:51 croc.go:1440: port: [9010]
[debug] 11:59:51 croc.go:1440: port: [9011]
[debug] 11:59:51 croc.go:1440: port: [9012]
[debug] 11:59:51 croc.go:1440: port: [9013]
[debug] 11:59:51 croc.go:1454: connecting to 192.168.42.127:9013
[debug] 11:59:51 comm.go:78: dialing to 192.168.42.127:9013 with timelimit 30s
[debug] 11:59:51 croc.go:1454: connecting to 192.168.42.127:9011
[debug] 11:59:51 comm.go:78: dialing to 192.168.42.127:9011 with timelimit 30s
[debug] 11:59:51 croc.go:1454: connecting to 192.168.42.127:9010
[debug] 11:59:51 comm.go:78: dialing to 192.168.42.127:9010 with timelimit 30s
[debug] 11:59:51 croc.go:1454: connecting to 192.168.42.127:9012
[debug] 11:59:51 comm.go:78: dialing to 192.168.42.127:9012 with timelimit 30s
[debug] 11:59:51 comm.go:87: connected to '192.168.42.127:9011'
[debug] 11:59:51 comm.go:87: connected to '192.168.42.127:9010'
[debug] 11:59:51 comm.go:87: connected to '192.168.42.127:9013'
[debug] 11:59:51 comm.go:87: connected to '192.168.42.127:9012'
[debug] 11:59:51 tcp.go:523: strong key: 27efc7af509674aa85302cb590a132652db90e8412ea5841672e717baeaef63f
[debug] 11:59:51 tcp.go:537: sending password
[debug] 11:59:51 tcp.go:548: waiting for first ok
[debug] 11:59:51 tcp.go:523: strong key: 97e18d7b8f31d474b05e8d57fc6a1692e5872a6dc2f6cc21426ea02fd6c92bd5
[debug] 11:59:51 tcp.go:566: sending room; 448a7ec0de8631886809d5f502d85e287691fb1bbf1284f75bd811fe3c349652-2
[debug] 11:59:51 tcp.go:577: waiting for room confirmation
[debug] 11:59:51 tcp.go:537: sending password
[debug] 11:59:51 tcp.go:548: waiting for first ok
[debug] 11:59:51 tcp.go:523: strong key: 6c3cdaca0449dfdfec5d37f9fe9aa66223ed10ae0462ef0586aa17a499c9e8ef
[debug] 11:59:51 tcp.go:537: sending password
[debug] 11:59:51 tcp.go:548: waiting for first ok
[debug] 11:59:51 tcp.go:593: all set
[debug] 11:59:51 croc.go:1463: connected to 192.168.42.127:9012
[debug] 11:59:51 tcp.go:566: sending room; 448a7ec0de8631886809d5f502d85e287691fb1bbf1284f75bd811fe3c349652-1
[debug] 11:59:51 tcp.go:577: waiting for room confirmation
[debug] 11:59:51 tcp.go:566: sending room; 448a7ec0de8631886809d5f502d85e287691fb1bbf1284f75bd811fe3c349652-0
[debug] 11:59:51 tcp.go:593: all set
[debug] 11:59:51 tcp.go:577: waiting for room confirmation
[debug] 11:59:51 croc.go:1463: connected to 192.168.42.127:9011
[debug] 11:59:51 tcp.go:593: all set
[debug] 11:59:51 croc.go:1463: connected to 192.168.42.127:9010
[debug] 11:59:51 tcp.go:523: strong key: 67c6cf622d4922f59dc1a9fab19a1987bb7f6c285b2d75e65675acb5bf47da87
[debug] 11:59:51 tcp.go:537: sending password
[debug] 11:59:51 tcp.go:548: waiting for first ok
[debug] 11:59:51 tcp.go:566: sending room; 448a7ec0de8631886809d5f502d85e287691fb1bbf1284f75bd811fe3c349652-3
[debug] 11:59:51 tcp.go:577: waiting for room confirmation
[debug] 11:59:51 tcp.go:593: all set
[debug] 11:59:51 croc.go:1463: connected to 192.168.42.127:9013
[debug] 11:59:51 croc.go:1472: sending external IP
[debug] 11:59:51 message.go:58: writing externalip message (encrypted)
[debug] 11:59:51 message.go:78: read externalip message (encrypted)
[debug] 11:59:51 croc.go:1483: received external IP: {"t":"externalip","m":"127.0.0.1:34011"}
[debug] 11:59:51 croc.go:1497: connected as 192.168.42.42:52595 -> 127.0.0.1:34011
[debug] 11:59:51 message.go:78: read fileinfo message (encrypted)
[debug] 11:59:51 croc.go:1280: using hash algorithm: xxhash
Accept 'DACT.rar' (34.8 MB)? (Y/n)

Receiving (<-127.0.0.1:34011)
[debug] 11:59:52 croc.go:1381: [{DACT.rar . C:\Users\jonas\Desktop [78 8 24 65 212 199 22 193] 36502593 2023-05-21 14:37:26.85 +0200 CEST false false  -rw-rw-rw- false false}]
[debug] 11:59:52 croc.go:1821: checking {Name:DACT.rar FolderRemote:. FolderSource:C:\Users\jonas\Desktop Hash:[78 8 24 65 212 199 22 193] Size:36502593 ModTime:2023-05-21 14:37:26.85 +0200 CEST IsCompressed:false IsEncrypted:false Symlink: Mode:-rw-rw-rw- TempFile:false IsIgnored:false}
[debug] 11:59:52 croc.go:1838: DACT.rar  4e081841d4c716c1 <nil>
[debug] 11:59:52 croc.go:1840: hashed DACT.rar to  using xxhash
[debug] 11:59:52 croc.go:1841: hashes are not equal  != 4e081841d4c716c1
[debug] 11:59:52 croc.go:1630: working on file 0
[debug] 11:59:52 croc.go:1715: converting to chunk range
 DACT.rar   0% |                    | ( 0 B/36 MB) [0s:0s][debug]       11:59:52 croc.go:1723: sending recipient ready with 0 chunks
[debug] 11:59:52 message.go:58: writing recipientready message (encrypted)
 DACT.rar 100% |████████████████████| (36/36 MB, 233 MB/s)
[debug] 11:59:52 croc.go:2035: finished receiving!
[debug] 11:59:52 croc.go:2039: Successful closing DACT.rar
[debug] 11:59:52 croc.go:2049: sending close-sender
[debug] 11:59:52 message.go:58: writing close-sender message (encrypted)
[debug] 11:59:52 message.go:78: read close-recipient message (encrypted)
[debug] 11:59:52 croc.go:1821: checking {Name:DACT.rar FolderRemote:. FolderSource:C:\Users\jonas\Desktop Hash:[78 8 24 65 212 199 22 193] Size:36502593 ModTime:2023-05-21 14:37:26.85 +0200 CEST IsCompressed:false IsEncrypted:false Symlink: Mode:-rw-rw-rw- TempFile:false IsIgnored:false}
[debug] 11:59:52 croc.go:1838: DACT.rar 4e081841d4c716c1 4e081841d4c716c1 <nil>
[debug] 11:59:52 croc.go:1863: hashes are equal 4e081841d4c716c1 == 4e081841d4c716c1
[debug] 11:59:52 croc.go:1690: finished
[debug] 11:59:52 message.go:58: writing finished message (encrypted)
[debug] 11:59:52 message.go:78: read finished message (encrypted)
[debug] 11:59:52 message.go:58: writing finished message (encrypted)

This seems to be a problem since several versions. I couldn't find out so far at which version this issue started to occur. However, there is no change in that behaviour if the peers use the same or different versions.

Any ideas or hints what I should have a look at to find out what's the issue?