putObject: Streaming uploads with size -1 should avoid erroring out f…

[harshavardhana]

…or missing parts.

size == -1 should be treated specially for putObjectStream() missing parts
shouldn't error out since with '-1' number of parts are dynamic only when
the stream ends we do know that the we have finished the upload.

Fixes - minio/mc#1819

[krishnasrinivas]

size == -1 should be treated specially for putObjectStream() and avoid fetching
partsInfo for previously uploaded parts since '-1' has no guarantee that the
data has no changed. Let the client upload again and not resume for unknown sizes.

but we check if part is already uploaded by checking ETag right? so if a stream is uploaded with size -1 with same data we will lose that optimization, right?

[harshavardhana]

but we check if part is already uploaded by checking ETag right? so if a stream is uploaded with size -1 with same data we will lose that optimization, right?

We can keep the optimization and just that we don't need to error out for '-1' size since the total parts are dynamic in that scenario.

[krishnasrinivas]

this will also cause data corruption if previous incomplete upload had more parts than the current upload. you can use:
for i := 1; i <= partNumber; i++ { to avoid that situation and also the if size < 0 { check below will not be needed if you use partNumber.

[harshavardhana]

Ah i see.