rustdoc: give proc-macros their own pages #54577

QuietMisdreavus · 2018-09-25T21:46:14Z

related to #49553 but i don't think it'll fix it

Currently, rustdoc doesn't expose proc-macros all that well. In the source crate, only their definition function is exposed, but when re-exported, they're treated as a macro! This is an awkward situation in all accounts. This PR checks functions to see whether they have any of #[proc_macro], #[proc_macro_attribute], or #[proc_macro_derive], and exposes them as macros instead. In addition, attributes and derives are exposed differently than other macros, getting their own item-type, CSS class, and module heading.

Function-like proc-macros are lumped in with macro_rules! macros, but they get a different declaration block (i'm open to tweaking this, it's just what i thought of given how function-proc-macros operate):

Proc-macro attributes and derives get their own pages, with a representative declaration block. Derive macros also show off their helper attributes:

There's one wrinkle which this PR doesn't address, which is why i didn't mark this as fixing the linked issue. Currently, proc-macros don't expose their attributes or source span across crates, so while rustdoc knows they exist, that's about all the information it gets. This leads to an "inlined" macro that has absolutely no docs on it, and no [src] link to show you where it was declared.

The way i got around it was to keep proc-macro re-export disabled, since we do get enough information across crates to properly link to the source page:

Until we can get a proc-macro's docs (and ideally also its source span) across crates, i believe this is the best way forward.

Proc-macros don't emit their attributes or source spans across crates. This means that rustdoc can't actually see the docs of a proc-macro if it wasn't defined in the active crate, and attempting to inline it creates an empty page with no docs or source link. In lieu of attempting to fix that immediately, this commit forces proc-macro re-exports to never inline, which at least creates usable links to complete documentation.

GuillaumeGomez · 2018-09-25T22:41:30Z

src/librustdoc/html/render.rs

+{
+    if m.kind == MacroKind::Bang {
+        write!(w, "<pre class='rust macro'>")?;
+        write!(w, "{}!() {{ /* proc-macro */ }}", it.name.as_ref().unwrap())?;


No unwrap please (expect!).

GuillaumeGomez · 2018-09-25T22:43:14Z

That's quite the nice add, thanks a lot!

However, the UI looks a bit... empty? At least it tells readers that it exists but not much more...

Centril · 2018-09-25T23:41:50Z

Function-like proc-macros are lumped in with macro_rules! macros

This is great; don't change it :)
I think it makes perfect sense for all bang macros to be lumped together.

QuietMisdreavus · 2018-09-26T14:00:34Z

However, the UI looks a bit... empty? At least it tells readers that it exists but not much more...

@GuillaumeGomez Yeah, there's not much to say generically about proc-macros in general, other than their name and form factor. (I mean, it's technically possible for a macro author to create some kind of BASIC dialect in one of these proc-macros...) It's up to the author to fill in how it's supposed to be used. I can change up the attribute and derive pages to give them a "declaration" block, though. That should help guide those pages some. (It's possible to gather a custom derive's helper attribute, so i should definitely figure out how to display that one...)

I think it makes perfect sense for all bang macros to be lumped together.

@Centril Yeah, at some point i realized there wasn't enough reason to separate macro_rules! macros and bang-proc-macros, so they're put under the same heading.

QuietMisdreavus · 2018-09-26T16:34:42Z

I've pushed up a couple new commits that add more information to attribute and derive pages. New images were added to the PR description to show off how they look now.

GuillaumeGomez · 2018-09-26T23:07:03Z

Seems good to me. A bit weird but as long as it's working... Please also add the proc-macros to the "all items" page (look for AllTypes).

QuietMisdreavus · 2018-09-27T14:29:59Z

Good catch! I've added sections to the "All items" page for attributes and derives, since function proc-macros already appear in the existing "Macros" section. I also found another issue where the link to the "all items" page was only being printed if the --crate-version argument was sent, so i went ahead and fixed that here.

GuillaumeGomez · 2018-09-27T15:15:55Z

Thanks for the fix. Please also add a test to check if they are correctly listed in the all items page (just add it to the all items test). Once done and CI green, r=me.

QuietMisdreavus · 2018-09-27T17:53:38Z

I added it to the proc-macro links test, so that i wouldn't have to mess with the crate type of the all-items test.

@bors r=GuillaumeGomez

bors · 2018-09-27T17:53:40Z

📌 Commit d37f369 has been approved by GuillaumeGomez

bors · 2018-09-28T18:30:36Z

⌛ Testing commit d37f369 with merge b26a7513c941147d087f6cae47f42649e7d49848...

bors · 2018-09-28T18:56:10Z

💔 Test failed - status-travis

rust-highfive · 2018-09-28T18:56:12Z

The job armhf-gnu 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_fold:end:system_info

Network availability confirmed.
Setting APT mirror in /etc/apt/sources.list: http://us-central1.gce.archive.ubuntu.com/ubuntu/
travis_fold:start:update_heroku
Updating Heroku
$ heroku version
heroku/7.16.0 linux-x64 node-v10.10.0
travis_fold:end:update_heroku
Installing APT Packages
travis_time:start:0a06fdd8
$ travis_apt_get_update
travis_time:end:0a06fdd8:start=1538159523378727802,finish=1538159528333874680,duration=4955146878
---
travis_time:end:354e0a50:start=1538160937446623206,finish=1538160937451140669,duration=4517463
travis_fold:end:after_failure.3
travis_fold:start:after_failure.4
travis_time:start:0e80f7ce
$ 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:0dae1878
travis_time:start:0dae1878
$ 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:2443d70d
$ 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)

alexcrichton · 2018-09-28T20:29:30Z

@bors: retry

…uillaumeGomez rustdoc: give proc-macros their own pages related to rust-lang#49553 but i don't think it'll fix it Currently, rustdoc doesn't expose proc-macros all that well. In the source crate, only their definition function is exposed, but when re-exported, they're treated as a macro! This is an awkward situation in all accounts. This PR checks functions to see whether they have any of `#[proc_macro]`, `#[proc_macro_attribute]`, or `#[proc_macro_derive]`, and exposes them as macros instead. In addition, attributes and derives are exposed differently than other macros, getting their own item-type, CSS class, and module heading. ![image](https://user-images.githubusercontent.com/5217170/46044803-6df8da00-c0e1-11e8-8c3b-25d2c3beb55c.png) Function-like proc-macros are lumped in with `macro_rules!` macros, but they get a different declaration block (i'm open to tweaking this, it's just what i thought of given how function-proc-macros operate): ![image](https://user-images.githubusercontent.com/5217170/46044828-84069a80-c0e1-11e8-9cc4-127e5477c395.png) Proc-macro attributes and derives get their own pages, with a representative declaration block. Derive macros also show off their helper attributes: ![image](https://user-images.githubusercontent.com/5217170/46094583-ef9f4500-c17f-11e8-8f71-fa0a7895c9f6.png) ![image](https://user-images.githubusercontent.com/5217170/46101529-cab3cd80-c191-11e8-857a-946897750da1.png) There's one wrinkle which this PR doesn't address, which is why i didn't mark this as fixing the linked issue. Currently, proc-macros don't expose their attributes or source span across crates, so while rustdoc knows they exist, that's about all the information it gets. This leads to an "inlined" macro that has absolutely no docs on it, and no `[src]` link to show you where it was declared. The way i got around it was to keep proc-macro re-export disabled, since we do get enough information across crates to properly link to the source page: ![image](https://user-images.githubusercontent.com/5217170/46045074-2cb4fa00-c0e2-11e8-81bc-33a8205fbd03.png) Until we can get a proc-macro's docs (and ideally also its source span) across crates, i believe this is the best way forward.

Rollup of 8 pull requests Successful merges: - #54564 (Add 1.29.1 release notes) - #54567 (Include path in stamp hash for debuginfo tests) - #54577 (rustdoc: give proc-macros their own pages) - #54590 (std: Don't let `rust_panic` get inlined) - #54598 (Remove useless lifetimes from `Pin` `impl`s.) - #54604 (Added help message for `self_in_typedefs` feature gate) - #54635 (Improve docs for std::io::Seek) - #54645 (Compute Android gdb version in compiletest)

bors · 2018-09-29T15:07:35Z

⌛ Testing commit d37f369 with merge 9653f79...

QuietMisdreavus added 3 commits September 25, 2018 14:56

handle proc-macros as macros instead of functions

aea1bd0

add test for proc-macro re-export

8f69a82

QuietMisdreavus mentioned this pull request Sep 25, 2018

rustdoc: Bad handling of proc_macro's re-exported via use_extern_macros #49553

Closed

GuillaumeGomez reviewed Sep 25, 2018

View reviewed changes

add declaration blocks to attribute/derive pages

869ebc4

XAMPPRocky added C-enhancement Category: An issue proposing an enhancement or a PR with one. A-macros Area: All kinds of macros (custom derive, macro_rules!, proc macros, ..) T-rustdoc Relevant to the rustdoc team, which will review and decide on the PR/issue. labels Sep 26, 2018

add derive macros' helper attributes to doc output

27429d9

QuietMisdreavus force-pushed the docs-for-procs branch from 2810709 to 27429d9 Compare September 26, 2018 18:40

QuietMisdreavus added 2 commits September 27, 2018 09:04

add attributes/derives to "all items" page

63ac3c7

show "all items" link even if crate doesn't have a version

967a6b0

check for proc-macros in "all items"

d37f369

bors added the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label Sep 27, 2018

bors added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Sep 28, 2018

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Sep 28, 2018

kennytm mentioned this pull request Sep 29, 2018

Rollup of 8 pull requests #54660

Merged

bors merged commit d37f369 into rust-lang:master Sep 29, 2018

ehuss mentioned this pull request Oct 27, 2018

cargo doc for proc macro reexports links to a page that doesnt exist. rust-lang/cargo#6224

Closed

QuietMisdreavus deleted the docs-for-procs branch November 1, 2018 19:18

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rustdoc: give proc-macros their own pages #54577

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QuietMisdreavus commented Sep 25, 2018 •

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rustdoc: give proc-macros their own pages #54577

rustdoc: give proc-macros their own pages #54577

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