On 25/08/16 08:56, Ms2ger wrote:
On 24/08/16 18:12, Lars Bergstrom wrote:
Currently, the GitHub Servo repository has 134,062 files... 131,477 of
which are in the tests/ directory. Of those, 102,871 are in the CSS WG
tests. I know it's not a perfect measure, but that's also 862megs of
the 1.132gb of disk space usage reported by `du` on macOS for a Servo
checkout.
So, I'd like to have a discussion to see if there's something we can
do here to reduce the number of files. There are two reasons this has
come up:
- If we do end up "copying" the Servo GitHub repository into the
Mozilla monorepo, unfortunately mercurial cannot scale to that number
of files (though there is work going on at Facebook to make it able to
do so in the next year or two). Plus, the non-CSS WG tests in the WPT
directory are duplicate with those already in m-c.
- That's a lot of disk space, and might not be needed for new
contributors who working on anything other than layout features.
There are a few options I can see here (apart from "do nothing"):
1) Reduce the duplication in the CSS WG tests. A lot of it is due to
the build system. How small could we get it? Similar to WPT (i.e., 10x
fewer files)?
2) Break out the CSS WG and WPT tests into a separate location, to be
downloaded as-needed. If we do this, though, what is the workflow for
adding, deleting, or correcting a test? And is it still just as easy
to run a single test? Jamming it in a crate will leave it in a wonky
directory (e.g., target/debug/build/csswg-7062634bbf237306/output)
that is not exactly awesome for viewing & running tests from.
Any opinions or other ideas here?
I vehemently object to moving wpt out of tree; that would significantly
discourage people from writing tests, especially tests that can be
shared with other browsers. (Shared tests are the single best way of
ensuring we are compatible with other browser engines, and they with us.)
The csswg tests have a number of issues resulting from the way their
build system works, but there's little point in spending resources
there; the built copy of the tests will be removed in the coming months,
as the unbuilt version will be added to wpt. (At that point: see the
paragraph above.)
I agree with Ms2ger. Maybe I should just make that my sig :) I think
it's easy to focus on the cost of these files and neglect the immense
value that they bring. AIUI once the build system is gone it will be
possible to directly contribute css tests upstream like we do with any
other kind of wpt tests.
As Simon estimates, without the build step, the number of files is
reduced by a factor of ~3. If that still isn't good enough it is
possible to consider hacks like never importing tests for specifications
that servo doesn't support yet, but those are intrinsically short-term
gains. There may also be some smaller, high-effort, but longer term
gains from things like merging (layoutwise) duplicate reference files.
However if servo/servo doesn't end up in m-c that seems like a
lower-value proposition (especially given that all of these files will
be in m-c anyway).
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