This cleans up the mutable-retrieve code a bit, and should fix some
corner cases where an offset/size combinations that reads the last byte
of the file (but not the first) could cause an assert to fire, making
the download hang. Should address ticket:2459 and ticket:2462.
This should tolerate offset/size combinations that read the last byte of
the file, something which was broken before. It quits early in the case
of zero-byte reads, to simplify the resulting "which segments do I need"
logic. Probably addresses ticket:2459.
The Docker build process seems to use 'git pull --depth=1', which
doesn't fetch enough history to see a tag, which means tahoe's setup.py
can't compute a version (then 'tahoe --version' reports "unknown").
Pulling a hundred commits should be enough to see a tag without making
the resulting image unnecessarily large. If we go more than 100 commits
between tags, we'll need to increase this, or come up with something
smarter.
It looks like DockerHub's automated builds only have access to the
subtree of the source checkout at+below the Dockerfile. Putting the
Dockerfile in misc/build_helpers/ meant that the build process only had
access to misc/build_helpers/, not the full source tree.
(An immutable collective directory could be interesting for some use cases, and is no more difficult to support.)
Signed-off-by: Daira Hopwood <daira@jacaranda.org>
test_cli.Help was too sensitive to the way that the --help output was
wrapped, which caused failures on travis when COLUMNS= was set low and
the expected strings were split across separate lines.
Also:
* do some light refactoring of create-client/node
* make it clear that these commands' --basedir options do the same as
the global --node-directory option
* use "global-options" instead of "global-opts"
Subcommands "--help" is now rendered as:
```
tahoe [global-options] COMMAND [options] ARGS
(use 'tahoe --help' to view global options)
USAGE (flags/options)
DESCRIPTION
DESCRIPTION_UNWRAPPED
```
The new .description and .description_unwrapped fields allow
commands (subclasses of twisted.python.usage.Usage) better control over
how their explanations are rendered: the old .longdesc field was wrapped
unpleasantly.
