Upload (sometimes?) ignores shares.happy in tahoe.cfg

[davidsarah]

kmarkley86 at 1212#comment:41:

I'm affected by the same fundamental problem [as #1212], but by a different path. The fix identified earlier was to immutable/repairer.py, but I'm getting an error from immutable/upload.py.

Scenario: I'm using 2-of-4 encoding with shares.happy=4 on tahoe 1.8.1. From the CLI I do a tahoe check --repair on a file with shares {0, 2, 3} already existing on the grid but share 1 not existing, and I get an UploadUnhappinessError complaining that "we were asked to place shares on at least 7" servers. There are only 4 servers on my grid -- hence my choice of shares.happy=4.

I observed that in immutable/upload.py, BaseUploadable has a statement "default_encoding_param_happy = 7". I tried the experiment of changing this value to 4 (the shares.happy value in my tahoe.cfg) and then the repair succeeds without error.

So there must be a path through this code where the default_encoding_param_happy value is actually used instead of being overridden by the value in tahoe.cfg. (I think it smells a little that this object has defaults at all, instead of requiring the parameters to be provided.)

A subsequent patch on trunk added assertions to try to catch the problem:

In 196bd583b6c4959c: Add assertions to make sure that set_default_encoding_parameters is always called, rather than using hardcoded 3/7/10 defaults. Also update affected tests. Note that this by itself cannot fix the bug mentioned in ticket:1212#comment:41, but it might make it easier to reproduce. refs #1212

kmarkley86: can you try again to reproduce the problem [] using trunk?

[warner]

kicking to 1.11 until we get this reproduced with the new assertions

[zooko]

Could this be related to #1847?