NewUsageValue exists to clip an oversized quota to the maximum value of an
int64, which is what dc95f36bc added it for when Box raised the Enterprise
space_amount to 1e+18 and started returning it as a float.
For the float64 instantiation the guard misses its own boundary.
float64(math.MaxInt64) is not 2**63-1, it rounds up to 2**63, so a quota of
exactly 2**63 fails the comparison and falls through to the int64 conversion,
which the spec leaves implementation dependent for an unrepresentable value.
On linux/amd64 it wraps:
Before: rclone about -> Total=-9223372036854775808
After: rclone about -> Total=9223372036854775807
A negative total is not just a wrong number. vfs.Statfs documents -1 as "not
known", vfs.fillInMissingSizes branches on total < 0, and serve sftp only
computes its usage percentage when total > 0, so the value is read back as a
missing quota.
The int64 and uint64 instantiations are unaffected, since for them
T(int64(math.MaxInt64)) is exact and clipping MaxInt64 to MaxInt64 is a no-op.
Set built the timetable with *x = append(*x, ts), so setting a bandwidth
timetable on a value that already held one kept both schedules. The single-value
branch of the same function has always done *x = BwTimetable{ts}, and the other
multi-token Set methods in this package build into a local and assign at the end.
The visible effect is through the rc API. The "main" options block registered in
fs.RegisterGlobalOptions is the live globalConfig, and options/set reshapes JSON
straight into it, so
rclone rc options/set --json '{"main": {"BwLimit": "Mon-10:00,1Mi"}}'
added to the running daemon's timetable rather than replacing it, and the older
slot kept winning: LimitAt for a Sunday returned the previous 10Mi. The same
applies to a _config override on a single call, since AddConfig shallow-copies
the global.
Building into a local also stops a failed parse from leaving the previous
timetable partly overwritten, which the existing error cases already expect.
youdie006andNick Craig-Wood