Fix theme-checker failure

[GuillaumeGomez]

Fixes #61145.

I didn't find a way to check it without strongly depending on the output... Is there a way to check if a program fails without checking its output?

r? @QuietMisdreavus

[czipperz]

You should probably add a regression test here if possible

[GuillaumeGomez]

@czipperz:

I didn't find a way to check it without strongly depending on the output... Is there a way to check if a program fails without checking its output?

[czipperz]

Try writing a test on this function?

[czipperz]

It doesn't even need to assert anything. TDD dictates you need a failing test case to change code. Panicking is failing the test

[czipperz]

Or assert_eq!(load_css_events(Vec::new()), Vec::new());

[czipperz]

Are you referring to a system level test here? That might be more difficult.

[GuillaumeGomez]

I was speaking at a system level, indeed. :) I'll add a function test instead.

[GuillaumeGomez]

I added a test but like I said, I don't think this is the best way. I guess it'll work for now...

[czipperz]

It seems the check pos + 1 < v.len() is duplicated multiple times in the while loop body. What do you think about eliminating these?

[GuillaumeGomez]

I think it's a valid request so I'll remove them.

[GuillaumeGomez]

Removed them!

[GuillaumeGomez]

r? @Manishearth

[Manishearth]

I don't really have time to review this rn.

[GuillaumeGomez]

Let's try someone else then!

cc @rust-lang/rustdoc

[GuillaumeGomez]

r? @ollie27

[GuillaumeGomez]

r? @kinnison

[kinnison]

A few comments, but otherwise LGTM. I'm not sure if I'm able to approve properly on this codebase but you have a 👍 from me modulo the query about panicing.

[GuillaumeGomez]

@kinnison Updated!

[rust-highfive]

The job x86_64-gnu-llvm-6.0 of your PR failed on Travis (raw log). Through arcane magic we have determined that the following fragments from the build log may contain information about the problem.

Click to expand the log.

travis_time:end:14d0619d:start=1561064659786871729,finish=1561064749216727195,duration=89429855466
$ git checkout -qf FETCH_HEAD
travis_fold:end:git.checkout

Encrypted environment variables have been removed for security reasons.
See https://docs.travis-ci.com/user/pull-requests/#pull-requests-and-security-restrictions
$ export SCCACHE_BUCKET=rust-lang-ci-sccache2
$ export SCCACHE_REGION=us-west-1
$ export GCP_CACHE_BUCKET=rust-lang-ci-cache
$ export AWS_ACCESS_KEY_ID=AKIA46X5W6CZEJZ6XT55
---
    100% |████████████████████████████████| 51kB 21.1MB/s 
Collecting colorama<=0.3.9,>=0.2.5 (from awscli)
  Downloading https://files.pythonhosted.org/packages/db/c8/7dcf9dbcb22429512708fe3a547f8b6101c0d02137acbd892505aee57adf/colorama-0.3.9-py2.py3-none-any.whl
Collecting botocore==1.12.173 (from awscli)
  Downloading https://files.pythonhosted.org/packages/af/bb/226c21c8ff37c620412280e71dd7b0135c50d380ac212e3cd0c34d4bc6ef/botocore-1.12.173-py2.py3-none-any.whl (5.6MB)
    0% |▏                               | 20kB 22.9MB/s eta 0:00:01
    0% |▏                               | 30kB 26.4MB/s eta 0:00:01
    0% |▎                               | 40kB 26.2MB/s eta 0:00:01
    0% |▎                               | 51kB 27.6MB/s eta 0:00:01
---
travis_time:start:test_assembly
Check compiletest suite=assembly mode=assembly (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
[01:03:49] 
[01:03:49] running 9 tests
[01:03:49] iiiiiiiii
[01:03:49] 
[01:03:49]  finished in 0.157
[01:03:49] travis_fold:end:test_assembly

---
travis_time:start:test_debuginfo
Check compiletest suite=debuginfo mode=debuginfo-gdb+lldb (x86_64-unknown-linux-gnu -> x86_64-unknown-linux-gnu)
[01:04:05] 
[01:04:05] running 122 tests
[01:04:30] .iiiii...i.....i..i...i..i.i.i..i.ii..i.i.....i..i....i..........iiii..........i...ii...i.......ii.i 100/122
[01:04:34] .i.i......iii.i.....ii
[01:04:34] 
[01:04:34]  finished in 29.721
[01:04:34] travis_fold:end:test_debuginfo

---
[01:05:42]    Compiling rustdoc v0.0.0 (/checkout/src/librustdoc)
[01:05:47] error[E0308]: mismatched types
[01:05:47]    --> src/librustdoc/theme.rs:106:28
[01:05:47]     |
[01:05:47] 106 |     v.get(pos + 1) == Some(b'/')
[01:05:47]     |                            |
[01:05:47]     |                            expected &u8, found u8
[01:05:47]     |                            help: consider borrowing here: `&b'/'`
[01:05:47]     |
---
travis_time:end:1c30a15d:start=1561068708004126374,finish=1561068708008816556,duration=4690182
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:02f0a7a4
$ ln -s . checkout && for CORE in obj/cores/core.*; do EXE=$(echo $CORE | sed 's|obj/cores/core\.[0-9]*\.!checkout!\(.*\)|\1|;y|!|/|'); if [ -f "$EXE" ]; then printf travis_fold":start:crashlog\n\033[31;1m%s\033[0m\n" "$CORE"; gdb --batch -q -c "$CORE" "$EXE" -iex 'set auto-load off' -iex 'dir src/' -iex 'set sysroot .' -ex bt -ex q; echo travis_fold":"end:crashlog; fi; done || true
travis_fold:end:after_failure.4
travis_fold:start:after_failure.5
travis_time:start:0a29a0da
travis_time:start:0a29a0da
$ cat ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers || true
cat: ./obj/build/x86_64-unknown-linux-gnu/native/asan/build/lib/asan/clang_rt.asan-dynamic-i386.vers: No such file or directory
travis_fold:end:after_failure.5
travis_fold:start:after_failure.6
travis_time:start:38540820
$ dmesg | grep -i kill

I'm a bot! I can only do what humans tell me to, so if this was not helpful or you have suggestions for improvements, please ping or otherwise contact @TimNN. (Feature Requests)

[kinnison]

Modulo the need for a borrow in that rewritten test, which I've just realised is in a non-public function so your comment about the guard in the public function meaning it won't be necessary anyway holds, 👍

[GuillaumeGomez]

Removed the last commit then. Thanks for your review!

@bors: r=kinnison

[bors]

📌 Commit 640bdbd has been approved by kinnison

[bors]

⌛ Testing commit 640bdbd with merge e562b24...