This helps make the Zulip development environment somewhat more robust
to new contributors, since it will give them a nice warning if they
try running any of our development tools outside the Zulip virtualenv.
Fixes#3468.
This is a fairly major overhaul of the CSS parser to support
line numbers in error messages.
Basically, instead of passing "slices" of tokens around, we pass
indexes into the token arrays to all of our sub-parsers, which
allows them to have access to previous tokens in certain cases.
This is particularly important for errors where stuff is missing
(vs. being wrong).
In testing this out I found a few more places to catch errors.
`tools/lint-all` now calls the new `tools/check-css`
The css_parser library parsers CSS into a data structure
that remembers line numbers and columns of semantically
meaningful tokens and adjoining white space/tokens. It
is intended to be used for various linting tasks.
The file `tools/check-css` runs a few files through the
parser and makes sure they round trip. This has some value
right away, as files that fail to parse will cause an
exception to be thrown and thus alert developers to syntax
errors. We expect to grow this into more advanced linting
tasks eventually.
sinwar
Steve Howell