use debug level for logs about bad package versioning

don't attempt retry of missing packages when updating index

Env for providers

rebar_package: do not return first package version for constraint with no match

Set unicode option for standard_io at entry point

fix hooks and plugins usage when cleaning build artifacts for deps

upgrade erlware commons and relx

Issue #1704: Fix alias provider argument passing

The way arguments are passed by the alias provider is not compatible
with all rebar providers/commands. Especially the release (relx)
provider does not like getting its arguments as a plain string. It
expects its arguments in a pre-parsed format as returned by
getopt:parse/2.

Other commands, e.g. eunit, seem to be fine with both ways of argument
passing. Therefore, this fix changes the alias provider argument passing
to the getopt format in general.

find_apps didn't read config files so no hooks were in the app_infos,
and now that hooks are being done rebar needs plugins to be able
to run clean plugin hooks in deps.

Corrected Erlang Solutions Download URL [skip ci]

Current URL goes to 404 page, corrected URL to avoid confusion.

Fix repeated bootstrap runs

Fix escriptize failure when ebin/ has subdirs

Although fairly irregular, the presence of a subdirectory in ebin/ while
running rebar3 escriptize would crash the run and generate a dump.

Since ebin subdirectories are generally not supported (adding a path for
an application only adds ebin/ and no subdirectories to the VM's path
set), we just silently ignore the directory altogether.

Fixes #1693

Updating the bootstrap script in #1689 made it so symlinks that already
exist return `exist` rather than ok, in line with the regular code.
However the bootstrap module wouldn't handle this case.

This fixes the problem by ensuring that `exists` is as valid as `ok`.

Update bootstrap script // fix windows issues

Update manpages

The bootstrap script has been mostly unchanged for a long period of
time, and has not benefited from all the changes and improvements that
rebar3 itself had, including (but not limited to) path escaping,
handling of directories on windows, and edge case management when it
comes to file and symlink handling.

This patch brings the updates seen in rebar_string_utils, rebar_utils,
and rebar_dir into the bootstrap script so that fewer people have build
issues when starting from source, from scratch.

New switches for cover, adding the alias provider, etc.

Prevent plugin unloading from killing currently running command (soft-purge in-compile)

Rather than the caller having to think of what to purge or not, use
erlang:check_process_code/2 to detect if the caller (rebar3) may die
because of the operation.

If so, do a soft purge with a conditional delete instead of a hard purge
with a mandatory delete.

Prevents the killing of a plugin with itself

Alias plugin promoted to built-in command

- Uses the code at https://github.com/tsloughter/rebar_alias and brings
  it within rebar3
- adds safety checks to prevent redefining built-in commands or obvious
  circular dependencies between commands (indirect circular deps are
  still possible)
- adds tests
- adds a systest to ensure no clash with the existing plugin

Fix file handling on Windows 7

Fix Plugin path handling (again!)

Support minimal coverage validation in tests

add eunit and ct option to set coverdata file name

Has no ill effect as tested on Win10

The path reloading of plugins had been fixed properly, but the problem
is that the paths it was using to re-load only considered the current
compile step, rather than the overall state of plugins. As such, the
reloaded paths after plugin compilation only reloaded the *latest*
plugin and not the other ones.

This fix forces the addition of all built plugin paths to the code paths
after a plugin compile job is run. This ensures that the path is clean
for initial plugin deps (only add those that are required), and is
re-made total after the fact (add all the plugins possible).

This commit also includes a system tests suite that can be run
optionally; the problem with this plugin mechanism was impossible to
find through mocked dependencies, and a working counterexample was
provided to us. The systest suite can be run against real projects
without conflict to make sure no regressions are hit.

fix code path when validating plugins

Adds an option (-m, --min_coverage, or {cover_opts, {min_coverage,X}})
to the 'cover' command, where the value is an integer between 0 and 100.

If the total coverage during the analysis is below the value received,
the command will fail with output like:

    ===> Requiring 64% coverage to pass. Only 62% obtained

If the rate is correct, the command silently passes as it currently
does.

This feature allows to enforce code coverage standards in a project if
desired.