Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Add explicit none() value variant in check-cfg #119473

Merged
merged 1 commit into from
Jan 13, 2024
Merged

Add explicit none() value variant in check-cfg #119473

merged 1 commit into from
Jan 13, 2024

Conversation

Urgau
Copy link
Member

@Urgau Urgau commented Dec 31, 2023 •
edited
Loading

This PR adds an explicit none value variant in check-cfg values: values(none()).

Currently the only way to define the none variant is with an empty values() which means that if someone has a cfg that takes none and strings they need to use two invocations: --check-cfg=cfg(foo) --check-cfg=cfg(foo, values("bar")).
Which would now be --check-cfg=cfg(foo, values(none(),"bar")), this is simpler and easier to understand.

--check-cfg=cfg(foo), --check-cfg=cfg(foo, values()) and --check-cfg=cfg(foo, values(none())) would be equivalent.

Another motivation for doing this is to make empty values() actually means no-values, but this is orthogonal to this PR and adding none() is sufficient in it-self.

@rustbot label +F-check-cfg
r? @petrochenkov

@rustbot rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. F-check-cfg --check-cfg labels Dec 31, 2023
@bors

This comment was marked as resolved.

Sign in to view
@Urgau Urgau force-pushed the check-cfg-explicit-none branch from 5f6f562 to 15078c2 Compare January 9, 2024 18:12
@petrochenkov
Copy link
Contributor

@bors r+

@bors
Copy link
Contributor

bors commented Jan 12, 2024

📌 Commit 15078c2 has been approved by petrochenkov

It is now in the queue for this repository.

@bors 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 Jan 12, 2024
@petrochenkov
Copy link
Contributor

Another motivation for doing this is to make empty values() actually means no-values

I don't understand this line though, what is the difference between "none" and "no-values"?

@bors
Copy link
Contributor

bors commented Jan 13, 2024

⌛ Testing commit 15078c2 with merge 7585c62...

@bors
Copy link
Contributor

bors commented Jan 13, 2024

☀️ Test successful - checks-actions
Approved by: petrochenkov
Pushing 7585c62 to master...

@bors bors added the merged-by-bors This PR was explicitly merged by bors. label Jan 13, 2024
@bors bors merged commit 7585c62 into rust-lang:master Jan 13, 2024
12 checks passed
@rustbot rustbot added this to the 1.77.0 milestone Jan 13, 2024
@rust-timer
Copy link
Collaborator

Finished benchmarking commit (7585c62): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This benchmark run did not return any relevant results for this metric.

Max RSS (memory usage)

Results

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

mean range count
Regressions ❌
(primary)		 2.1% [2.1%, 2.1%] 1
Regressions ❌
(secondary)		 2.6% [2.6%, 2.6%] 2
Improvements ✅
(primary)		 - - 0
Improvements ✅
(secondary)		 - - 0
All ❌✅ (primary) 2.1% [2.1%, 2.1%] 1

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

This benchmark run did not return any relevant results for this metric.

Bootstrap: 668.566s -> 668.237s (-0.05%)
Artifact size: 308.16 MiB -> 308.17 MiB (0.01%)

@Urgau Urgau mentioned this pull request Jan 13, 2024
Merged
@Urgau
Copy link
Member Author

Urgau commented Jan 13, 2024

Another motivation for doing this is to make empty values() actually means no-values

I don't understand this line though, what is the difference between "none" and "no-values"?

I have opened #119930 to explain and tackle this; but to simplify, an empty values() currently means the same as values(none()), i.e. an expected list of values with the none variant (as in #[cfg(name)] where the value is none). I propose to remove this confusing meaning by making an empty values() actually mean a empty set of expected values.
See more details and explanation in the PR.

@petrochenkov
Copy link
Contributor

@Urgau
I see, I initially thought that the "empty set of expected values" would be meaningless (you just don't add the name to the set of expected names in that case), but #119930 shows why it may make sense.

bors added a commit to rust-lang-ci/rust that referenced this pull request Jan 17, 2024
@bors
Auto merge of rust-lang#119930 - Urgau:check-cfg-empty-values-means-e…
c58a5da 
…mpty, r=petrochenkov

Add way to express that no values are expected with check-cfg

This PR adds way to express no-values (no values expected) with `--check-cfg` by making empty `values()` no longer mean `values(none())` (internal: `&[None]`) and now be an empty list (internal: `&[]`).

### Context

Currently `--check-cfg` has a way to express that _any value is expected_ with `values(any())`, but has no way to do the inverse and say that _no value is expected_.

This would be particularly useful for build systems that control a config name and it's values as they could always declare a config name as expected and if in the current state they have values pass them and if not pass an empty list.

To give a more concrete example, Cargo `--check-cfg` currently needs to generate:
 - `--check-cfg=cfg(feature, values(...))` for the case with declared features
 - and `--check-cfg=cfg()` for the case without any features declared

This means that when there are no features declared, users will get an `unexpected config name` but from the point of view of Cargo the config name `feature` is expected, it's just that for now there aren't any values for it.

See [Cargo `check_cfg_args` function](https://github.com/rust-lang/cargo/blob/92395d90106b3b61bcb68bcf2069052c93771764/src/cargo/core/compiler/mod.rs#L1263-L1281) for more details.

### De-specializing *empty* `values()`

To solve this issue I propose that we "de-specialize" empty `values()` to no longer mean `values(none())` but to actually mean empty set/list. This is one of the last source of confusion for my-self and others with the `--check-cfg` syntax.

> The confusing part here is that an empty `values()` currently means the same as `values(none())`, i.e. an expected list of values with the _none_ variant (as in `#[cfg(name)]` where the value is none) instead of meaning an empty set.

Before the new `cfg()` syntax, defining the _none_ variant was only possible under certain circumstances, so in rust-lang#111068 I decided to make `values()` to mean the _none_ variant, but it is no longer necessary since rust-lang#119473 which introduced the `none()` syntax.

A simplified representation of the proposed "de-specialization" would be:

| Syntax                                  | List/set of expected values |
|-----------------------------------------|-----------------------------|
| `cfg(name)`/`cfg(name, values(none()))` | `&[None]`                   |
| `cfg(name, values())`                   | `&[]`                       |

Note that I have my-self made the mistake of using an empty `values()` as meaning empty set, see rust-lang/cargo#13011.

`@rustbot` label +F-check-cfg
r? `@petrochenkov`
cc `@epage`
github-actions bot pushed a commit to rust-lang/miri that referenced this pull request Jan 18, 2024
@bors
Auto merge of #119930 - Urgau:check-cfg-empty-values-means-empty, r=p…
ae6972c 
…etrochenkov

Add way to express that no values are expected with check-cfg

This PR adds way to express no-values (no values expected) with `--check-cfg` by making empty `values()` no longer mean `values(none())` (internal: `&[None]`) and now be an empty list (internal: `&[]`).

### Context

Currently `--check-cfg` has a way to express that _any value is expected_ with `values(any())`, but has no way to do the inverse and say that _no value is expected_.

This would be particularly useful for build systems that control a config name and it's values as they could always declare a config name as expected and if in the current state they have values pass them and if not pass an empty list.

To give a more concrete example, Cargo `--check-cfg` currently needs to generate:
 - `--check-cfg=cfg(feature, values(...))` for the case with declared features
 - and `--check-cfg=cfg()` for the case without any features declared

This means that when there are no features declared, users will get an `unexpected config name` but from the point of view of Cargo the config name `feature` is expected, it's just that for now there aren't any values for it.

See [Cargo `check_cfg_args` function](https://github.com/rust-lang/cargo/blob/92395d90106b3b61bcb68bcf2069052c93771764/src/cargo/core/compiler/mod.rs#L1263-L1281) for more details.

### De-specializing *empty* `values()`

To solve this issue I propose that we "de-specialize" empty `values()` to no longer mean `values(none())` but to actually mean empty set/list. This is one of the last source of confusion for my-self and others with the `--check-cfg` syntax.

> The confusing part here is that an empty `values()` currently means the same as `values(none())`, i.e. an expected list of values with the _none_ variant (as in `#[cfg(name)]` where the value is none) instead of meaning an empty set.

Before the new `cfg()` syntax, defining the _none_ variant was only possible under certain circumstances, so in rust-lang/rust#111068 I decided to make `values()` to mean the _none_ variant, but it is no longer necessary since rust-lang/rust#119473 which introduced the `none()` syntax.

A simplified representation of the proposed "de-specialization" would be:

| Syntax                                  | List/set of expected values |
|-----------------------------------------|-----------------------------|
| `cfg(name)`/`cfg(name, values(none()))` | `&[None]`                   |
| `cfg(name, values())`                   | `&[]`                       |

Note that I have my-self made the mistake of using an empty `values()` as meaning empty set, see rust-lang/cargo#13011.

`@rustbot` label +F-check-cfg
r? `@petrochenkov`
cc `@epage`
This was referenced Jan 18, 2024
Closed
Closed
lnicola pushed a commit to lnicola/rust-analyzer that referenced this pull request Apr 7, 2024
@bors
Auto merge of #119930 - Urgau:check-cfg-empty-values-means-empty, r=p…
44ce579 
…etrochenkov

Add way to express that no values are expected with check-cfg

This PR adds way to express no-values (no values expected) with `--check-cfg` by making empty `values()` no longer mean `values(none())` (internal: `&[None]`) and now be an empty list (internal: `&[]`).

### Context

Currently `--check-cfg` has a way to express that _any value is expected_ with `values(any())`, but has no way to do the inverse and say that _no value is expected_.

This would be particularly useful for build systems that control a config name and it's values as they could always declare a config name as expected and if in the current state they have values pass them and if not pass an empty list.

To give a more concrete example, Cargo `--check-cfg` currently needs to generate:
 - `--check-cfg=cfg(feature, values(...))` for the case with declared features
 - and `--check-cfg=cfg()` for the case without any features declared

This means that when there are no features declared, users will get an `unexpected config name` but from the point of view of Cargo the config name `feature` is expected, it's just that for now there aren't any values for it.

See [Cargo `check_cfg_args` function](https://github.com/rust-lang/cargo/blob/92395d90106b3b61bcb68bcf2069052c93771764/src/cargo/core/compiler/mod.rs#L1263-L1281) for more details.

### De-specializing *empty* `values()`

To solve this issue I propose that we "de-specialize" empty `values()` to no longer mean `values(none())` but to actually mean empty set/list. This is one of the last source of confusion for my-self and others with the `--check-cfg` syntax.

> The confusing part here is that an empty `values()` currently means the same as `values(none())`, i.e. an expected list of values with the _none_ variant (as in `#[cfg(name)]` where the value is none) instead of meaning an empty set.

Before the new `cfg()` syntax, defining the _none_ variant was only possible under certain circumstances, so in rust-lang/rust#111068 I decided to make `values()` to mean the _none_ variant, but it is no longer necessary since rust-lang/rust#119473 which introduced the `none()` syntax.

A simplified representation of the proposed "de-specialization" would be:

| Syntax                                  | List/set of expected values |
|-----------------------------------------|-----------------------------|
| `cfg(name)`/`cfg(name, values(none()))` | `&[None]`                   |
| `cfg(name, values())`                   | `&[]`                       |

Note that I have my-self made the mistake of using an empty `values()` as meaning empty set, see rust-lang/cargo#13011.

`@rustbot` label +F-check-cfg
r? `@petrochenkov`
cc `@epage`
RalfJung pushed a commit to RalfJung/rust-analyzer that referenced this pull request Apr 27, 2024
@bors
Auto merge of #119930 - Urgau:check-cfg-empty-values-means-empty, r=p…
a8a0df1 
…etrochenkov

Add way to express that no values are expected with check-cfg

This PR adds way to express no-values (no values expected) with `--check-cfg` by making empty `values()` no longer mean `values(none())` (internal: `&[None]`) and now be an empty list (internal: `&[]`).

### Context

Currently `--check-cfg` has a way to express that _any value is expected_ with `values(any())`, but has no way to do the inverse and say that _no value is expected_.

This would be particularly useful for build systems that control a config name and it's values as they could always declare a config name as expected and if in the current state they have values pass them and if not pass an empty list.

To give a more concrete example, Cargo `--check-cfg` currently needs to generate:
 - `--check-cfg=cfg(feature, values(...))` for the case with declared features
 - and `--check-cfg=cfg()` for the case without any features declared

This means that when there are no features declared, users will get an `unexpected config name` but from the point of view of Cargo the config name `feature` is expected, it's just that for now there aren't any values for it.

See [Cargo `check_cfg_args` function](https://github.com/rust-lang/cargo/blob/92395d90106b3b61bcb68bcf2069052c93771764/src/cargo/core/compiler/mod.rs#L1263-L1281) for more details.

### De-specializing *empty* `values()`

To solve this issue I propose that we "de-specialize" empty `values()` to no longer mean `values(none())` but to actually mean empty set/list. This is one of the last source of confusion for my-self and others with the `--check-cfg` syntax.

> The confusing part here is that an empty `values()` currently means the same as `values(none())`, i.e. an expected list of values with the _none_ variant (as in `#[cfg(name)]` where the value is none) instead of meaning an empty set.

Before the new `cfg()` syntax, defining the _none_ variant was only possible under certain circumstances, so in rust-lang/rust#111068 I decided to make `values()` to mean the _none_ variant, but it is no longer necessary since rust-lang/rust#119473 which introduced the `none()` syntax.

A simplified representation of the proposed "de-specialization" would be:

| Syntax                                  | List/set of expected values |
|-----------------------------------------|-----------------------------|
| `cfg(name)`/`cfg(name, values(none()))` | `&[None]`                   |
| `cfg(name, values())`                   | `&[]`                       |

Note that I have my-self made the mistake of using an empty `values()` as meaning empty set, see rust-lang/cargo#13011.

`@rustbot` label +F-check-cfg
r? `@petrochenkov`
cc `@epage`
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Reviewers
No reviews
Assignees

@petrochenkov petrochenkov

Labels
F-check-cfg --check-cfg merged-by-bors This PR was explicitly merged by bors. S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue.
Projects
None yet
Milestone
1.77.0
Development

Successfully merging this pull request may close these issues.
5 participants
@Urgau @bors @petrochenkov @rust-timer @rustbot