Add the -Zcrate-attr=foo unstable rustc option #52355

pietroalbini · 2018-07-13T20:55:59Z

This PR adds a new unstable option to rustc: -Zcrate-attr=foo. The option can be used to inject crate-level attributes from the CLI, and it's meant to be used by tools like Crater that needs to add their own attributes to a crate without changing the source code.

The exact reason I need this is to implement "edition runs" in Crater: we need to add the preview feature flag to every crate, and editing the crates' source code on the fly might produce unexpected results, while a compiler flag is more reliable.

cc rust-lang/crater#282 @Mark-Simulacrum

rust-highfive · 2018-07-13T20:56:02Z

r? @eddyb

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nagisa · 2018-07-13T21:34:39Z

Would it be possible to generalize to a -Zattr='any attr'? That would be useful for more tools and testing scenarios.

pietroalbini · 2018-07-13T22:01:51Z

Hmm, what other attributes did you have in mind? I can't think of many of them that apply to the whole crate and can be useful to dynamically add.

eddyb · 2018-07-14T17:24:31Z

@pietroalbini I was discussing a while back "custom test frameworks" with @Manishearth, and this came up: the usecases I had in mind were injecting #![test] at the crate level, from --test (to trigger the test harness transformation), and maybe even e.g. -A foo -> #![allow(foo)].

Also there are some things like crate name, type, recursion limits, etc. where it'd be nice if there was a common interface (e.g. -a 'foo(bar)'), with existing flags explicitly marked as shorthands.

EDIT: @michaelwoerister might have some opinions regarding incremental, but I think such a flag would simplify things, by modifying the input source code itself, rather than being a side-channel.

eddyb · 2018-07-14T17:27:10Z

src/librustc/session/config.rs

@@ -1351,6 +1351,8 @@ options! {DebuggingOptions, DebuggingSetter, basic_debugging_options,
          "generate build artifacts that are compatible with linker-based LTO."),
    no_parallel_llvm: bool = (false, parse_bool, [UNTRACKED],
          "don't run LLVM in parallel (while keeping codegen-units and ThinLTO)"),
+    feature: Vec<String> = (Vec::new(), parse_string_push, [UNTRACKED],


cc @michaelwoerister on the UNTRACKED here - I think you can only do this if you actually modify the AST to include explicit attributes (which I think we should do).
Also, it'd be easier to handle e.g. the "unused feature" lint, if we have the attributes in the AST.

Modifying the AST would probably work for incremental, yes, but it also seems .. like overkill? In particular, the reason for this change is to unblock our ability to run a crater run and test the Edition migration, so I'd hate to just stall out on possible future improvements. We could just make the attribute [TRACKED].

Where would you propose doing the AST modification exactly?

I was working on converting this PR to -Zcrate-attr=feature(foo) (wip branch), but I don't have time to finish it now (maybe in a few days). If you want to merge this as soon as possible I can do a quick commit changing the flag to [TRACKED], and then I can open a new PR implementing -Zcrate-attr and reverting this one.

Oh @nikomatsakis, now that I think about it, if we want to do a crater run as soon as possible we could also @bors try this and use this PR as the second crater toolchain.

Good point.

pietroalbini · 2018-07-19T15:58:26Z

Let's get a toolchain built for the edition crater run.

@bors try

bors · 2018-07-19T15:58:38Z

⌛ Trying commit bce31ea with merge 37c9dc8...

@Mark-Simulacrum

Add the -Zfeature=foo unstable rustc option This PR adds a new unstable option to `rustc`: `-Zfeature=foo`. The option can be used to enable nightly features from the CLI, and it's meant to be used by tools like Crater to try enabling features without changing the crate's source code. The exact reason I need this is to implement "edition runs" in Crater: we need to add the preview feature flag to every crate, and editing the crates' source code on the fly might produce unexpected results, while a compiler flag is more reliable. Obviously this won't be stabilized in the future. cc rust-lang/crater#282 @Mark-Simulacrum

bors · 2018-07-19T17:42:52Z

☀️ Test successful - status-travis
State: approved= try=True

pietroalbini · 2018-07-27T16:55:26Z

Ok, implemented -Zcrate-attr instead of -Zfeature, and while it works fine, some diagnostics are really bad. When there is a parse error the correct message is displayed:

$ rustc foo.rs -Zcrate-attr=10
error: expected identifier, found `10`
 --> <crate attribute>:1:1
  |
1 | 10
  | ^^ expected identifier

But when another part of rustc raises an error about that attribute the spans are messed up (showing the crate code instead of the attribute):

$ rustc foo.rs "-Zcrate-attr=feature(10)"
error[E0556]: malformed feature, expected just one word
 --> foo.rs:1:9
  |
1 | #![allow(dead_code)]
  |         ^^

error[E0658]: non-string literals in attributes, or string literals in top-level positions, are experimental (see issue #34981)
 --> foo.rs:1:1
  |
1 | #![allow(dead_code)]
  | ^^^^^^^^^^^
  |
  = help: add #![feature(attr_literals)] to the crate attributes to enable

pietroalbini · 2018-07-27T17:52:53Z

Diagnostics fixed. This should be ready for a review now.

pietroalbini · 2018-07-28T16:14:32Z

@bors try

bors · 2018-07-28T16:14:43Z

⌛ Trying commit 71276c6 with merge 52fa4de...

@Mark-Simulacrum

Add the -Zcrate-attr=foo unstable rustc option This PR adds a new unstable option to `rustc`: `-Zcrate-attr=foo`. The option can be used to inject crate-level attributes from the CLI, and it's meant to be used by tools like Crater that needs to add their own attributes to a crate without changing the source code. The exact reason I need this is to implement "edition runs" in Crater: we need to add the preview feature flag to every crate, and editing the crates' source code on the fly might produce unexpected results, while a compiler flag is more reliable. cc rust-lang/crater#282 @Mark-Simulacrum

bors · 2018-07-28T17:52:03Z

☀️ Test successful - status-travis
State: approved= try=True

eddyb · 2018-07-28T20:57:56Z

@bors r+

bors · 2018-07-28T20:57:57Z

📌 Commit 71276c6 has been approved by eddyb

Manishearth · 2018-07-28T21:24:34Z

cc @djrenren this may be useful for custom test frameworks

bors · 2018-07-28T23:10:17Z

⌛ Testing commit 71276c6 with merge 6323d9a...

@Mark-Simulacrum

Add the -Zcrate-attr=foo unstable rustc option This PR adds a new unstable option to `rustc`: `-Zcrate-attr=foo`. The option can be used to inject crate-level attributes from the CLI, and it's meant to be used by tools like Crater that needs to add their own attributes to a crate without changing the source code. The exact reason I need this is to implement "edition runs" in Crater: we need to add the preview feature flag to every crate, and editing the crates' source code on the fly might produce unexpected results, while a compiler flag is more reliable. cc rust-lang/crater#282 @Mark-Simulacrum

bors · 2018-07-29T01:14:33Z

☀️ Test successful - status-appveyor, status-travis
Approved by: eddyb
Pushing 6323d9a to master...

rust-highfive assigned eddyb Jul 13, 2018

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jul 13, 2018

eddyb reviewed Jul 14, 2018

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pietroalbini added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jul 15, 2018

pietroalbini force-pushed the zfeature branch from e3ac68e to bce31ea Compare July 19, 2018 15:57

pietroalbini force-pushed the zfeature branch 2 times, most recently from 92fb368 to 277fbf3 Compare July 27, 2018 16:49

pietroalbini changed the title ~~Add the -Zfeature=foo unstable rustc option~~ Add the -Zcrate-attr=foo unstable rustc option Jul 27, 2018

Add the -Zcrate-attr=foo nightly rustc flag to inject crate attributes

71276c6

pietroalbini force-pushed the zfeature branch from 277fbf3 to 71276c6 Compare July 27, 2018 17:51

pietroalbini added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jul 27, 2018

bors removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label Jul 28, 2018

bors added the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label Jul 28, 2018

bors merged commit 71276c6 into rust-lang:master Jul 29, 2018

pietroalbini deleted the zfeature branch July 29, 2018 10:37

pnkfelix mentioned this pull request Oct 9, 2018

error: internal compiler error: Accessing (*_310) with the kind Write(Move) shouldn't be possible #54597

Closed

ojeda mentioned this pull request Jan 20, 2022

Rust unstable features needed for the kernel Rust-for-Linux/linux#2

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90 tasks

kyrias mentioned this pull request Jul 18, 2023

Add an option to exclude source code from docs #75497

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jieyouxu mentioned this pull request Aug 23, 2024

[CRATER RUN DO NOT MERGE] crater run to evaluate effectiveness of lint for if_let_rescope #129466

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Add the -Zcrate-attr=foo unstable rustc option #52355

Add the -Zcrate-attr=foo unstable rustc option #52355

pietroalbini commented Jul 13, 2018 •

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Add the -Zcrate-attr=foo unstable rustc option #52355

Add the -Zcrate-attr=foo unstable rustc option #52355

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