I have verified that the following issue works under 7.4.2 correctly.
If a file is a gzip file it can not be decombressed under 7.5.0. The following log messages are provided:
ERROR [s3] s3/input.go:259 handleS3Objects failed: newS3BucketReader failed: Failed to decompress gzipped file s3file.txt.gz: gzip: invalid header
panic: send on closed channel
goroutine 121 [running]:
github.com/elastic/beats/x-pack/filebeat/input/s3.(*s3Input).processMessage(0xc0000db340, 0x34b5c20, 0xc000484190, 0x0, 0xc0009d0250, 0xc0009d02d0, 0x0, 0x0, 0xc0009d0300, 0xc0009d0330, ...)
/go/src/github.com/elastic/beats/x-pack/filebeat/input/s3/input.go:260 +0x2f6
created by github.com/elastic/beats/x-pack/filebeat/input/s3.(*s3Input).processor
/go/src/github.com/elastic/beats/x-pack/filebeat/input/s3/input.go:240 +0x19c