Make `#[diagnostic::on_unimplemented]` format string parsing more robust #122402

weiznich · 2024-03-12T19:20:53Z

This commit fixes several issues with the format string parsing of the #[diagnostic::on_unimplemented] attribute that were pointed out by @ehuss.
In detail it fixes:

Appearing format specifiers (display, etc). For these we generate a warning that the specifier is unsupported. Otherwise we ignore them
Positional arguments. For these we generate a warning that positional arguments are unsupported in that location and replace them with the format string equivalent (so {} or {n} where n is the index of the positional argument)
Broken format strings with enclosed }. For these we generate a warning about the broken format string and set the emitted message literally to the provided unformatted string
Unknown format specifiers. For these we generate an additional warning about the unknown specifier. Otherwise we emit the literal string as message.

This essentially makes those strings behave like format! with the minor difference that we do not generate hard errors but only warnings. After that we continue trying to do something unsuprising (mostly either ignoring the broken parts or falling back to just giving back the literal string as provided).

Fix #122391

r? @compiler-errors

weiznich · 2024-03-12T19:21:46Z

compiler/rustc_trait_selection/messages.ftl

@@ -60,3 +66,6 @@ trait_selection_unable_to_construct_constant_value = unable to construct a const

 trait_selection_unknown_format_parameter_for_on_unimplemented_attr = there is no parameter `{$argument_name}` on trait `{$trait_name}`
    .help = expect either a generic argument name or {"`{Self}`"} as format argument
+
+trait_selection_wrapped_parser_error = {$description}


I'm a bit unsure about that "hack". That's here to forward the values of ParserError as lint. I'm not sure if there is a better way of doing that. If that's the case I'm happy to change it.

It's fine until these parsing errors become translatable.

compiler-errors · 2024-03-20T20:07:06Z

compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs

+        if self.is_diagnostic_namespace_variant && !parser.errors.is_empty() {
+            String::from(s)
+        } else {
+            constructed_message
+        }


This seems subtle. Please document why we need this.

compiler-errors · 2024-03-20T20:08:04Z

compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs

+                    UNKNOWN_OR_MALFORMED_DIAGNOSTIC_ATTRIBUTES,
+                    tcx.local_def_id_to_hir_id(item_def_id.expect_local()),
+                    self.span,
+                    WrappedParserError { description: e.description, label: e.label },


Kind of a hack, but I guess it's fine

compiler-errors · 2024-03-20T20:08:16Z

compiler/rustc_trait_selection/src/traits/error_reporting/on_unimplemented.rs

+                }
+            }
+        }
+        if self.is_diagnostic_namespace_variant {


Please leave a comment here explaining why we need to report these.

Also, we should perhaps do the same as above and just report them as struct_span_err. Seems useful to report even for the rustc_ variant.

compiler-errors · 2024-03-20T20:09:51Z

This I think needs to get backported so it is stabilized at the same time as diagnostic::on_unimplemented.

@ehuss

This commit fixes several issues with the format string parsing of the `#[diagnostic::on_unimplemented]` attribute that were pointed out by @ehuss. In detail it fixes: * Appearing format specifiers (display, etc). For these we generate a warning that the specifier is unsupported. Otherwise we ignore them * Positional arguments. For these we generate a warning that positional arguments are unsupported in that location and replace them with the format string equivalent (so `{}` or `{n}` where n is the index of the positional argument) * Broken format strings with enclosed }. For these we generate a warning about the broken format string and set the emitted message literally to the provided unformatted string * Unknown format specifiers. For these we generate an additional warning about the unknown specifier. Otherwise we emit the literal string as message. This essentially makes those strings behave like `format!` with the minor difference that we do not generate hard errors but only warnings. After that we continue trying to do something unsuprising (mostly either ignoring the broken parts or falling back to just giving back the literal string as provided). Fix rust-lang#122391

compiler-errors · 2024-03-21T16:37:34Z

@bors r+

bors · 2024-03-21T16:37:36Z

📌 Commit 5568c56 has been approved by compiler-errors

It is now in the queue for this repository.

…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#122402 (Make `#[diagnostic::on_unimplemented]` format string parsing more robust) - rust-lang#122644 (pattern analysis: add a custom test harness) - rust-lang#122733 (Strip placeholders from hidden types before remapping generic parameter) - rust-lang#122752 (Interpolated cleanups) - rust-lang#122771 (add some comments to hir::ModuleItems) - rust-lang#122793 (Implement macro-based deref!() syntax for deref patterns) - rust-lang#122810 (Remove `target_override`) - rust-lang#122827 (Remove unnecessary braces from `bug`/`span_bug`) r? `@ghost` `@rustbot` modify labels: rollup

Rollup merge of rust-lang#122402 - weiznich:fix/122391, r=compiler-errors Make `#[diagnostic::on_unimplemented]` format string parsing more robust This commit fixes several issues with the format string parsing of the `#[diagnostic::on_unimplemented]` attribute that were pointed out by `@ehuss.` In detail it fixes: * Appearing format specifiers (display, etc). For these we generate a warning that the specifier is unsupported. Otherwise we ignore them * Positional arguments. For these we generate a warning that positional arguments are unsupported in that location and replace them with the format string equivalent (so `{}` or `{n}` where n is the index of the positional argument) * Broken format strings with enclosed }. For these we generate a warning about the broken format string and set the emitted message literally to the provided unformatted string * Unknown format specifiers. For these we generate an additional warning about the unknown specifier. Otherwise we emit the literal string as message. This essentially makes those strings behave like `format!` with the minor difference that we do not generate hard errors but only warnings. After that we continue trying to do something unsuprising (mostly either ignoring the broken parts or falling back to just giving back the literal string as provided). Fix rust-lang#122391 r? `@compiler-errors`

weiznich · 2024-03-22T06:54:12Z

@compiler-errors What is the usual procedure for the backport? Is there anything that I can do or does this happen "automatically"?

apiraino · 2024-03-24T22:30:22Z

Beta backport approved as per compiler team on Zulip. A backport PR will be authored by the release team at the end of the current development cycle.

(sorry for the delay)

@rustbot label +beta-accepted

[beta] backports - Do not eat nested expressions' results in `MayContainYieldPoint` format args visitor rust-lang#122680 - Fix heading anchors in doc pages. rust-lang#122693 - Make `#[diagnostic::on_unimplemented]` format string parsing more robust rust-lang#122402 r? cuviper

[beta] backports - Do not eat nested expressions' results in `MayContainYieldPoint` format args visitor rust-lang#122680 - Fix heading anchors in doc pages. rust-lang#122693 - Make `#[diagnostic::on_unimplemented]` format string parsing more robust rust-lang#122402 - Update ninja on Windows rust-lang#123178 r? cuviper

Updated in rust-lang/rust#122402

rustbot assigned compiler-errors Mar 12, 2024

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. labels Mar 12, 2024

weiznich commented Mar 12, 2024

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This was referenced Mar 12, 2024

on_unimplemented format strings either error or warn or ignore various formatting issues #122391

Closed

Add the #[diagnostic] attribute namespace and the #[diagnostic::on_unimplemented] feature to the reference rust-lang/reference#1449

Merged

compiler-errors reviewed Mar 20, 2024

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compiler-errors added the beta-nominated Nominated for backporting to the compiler in the beta channel. label Mar 20, 2024

weiznich force-pushed the fix/122391 branch from b9420a5 to 5568c56 Compare March 21, 2024 07:27

compiler-errors approved these changes Mar 21, 2024

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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 Mar 21, 2024

matthiaskrgr mentioned this pull request Mar 21, 2024

Rollup of 8 pull requests #122830

Merged

bors merged commit 2e41425 into rust-lang:master Mar 21, 2024
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rustbot added this to the 1.79.0 milestone Mar 21, 2024

rustbot added the beta-accepted Accepted for backporting to the compiler in the beta channel. label Mar 24, 2024

cuviper mentioned this pull request Mar 28, 2024

[beta] backports #123172

Merged

cuviper modified the milestones: 1.79.0, 1.78.0 Mar 28, 2024

cuviper removed the beta-nominated Nominated for backporting to the compiler in the beta channel. label Mar 28, 2024

ehuss added a commit to weiznich/reference that referenced this pull request Apr 3, 2024

Update on_unimplemented for format string changes.

52874b8

Updated in rust-lang/rust#122402

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Make `#[diagnostic::on_unimplemented]` format string parsing more robust #122402

Make `#[diagnostic::on_unimplemented]` format string parsing more robust #122402

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apiraino commented Mar 24, 2024 •

edited

Make #[diagnostic::on_unimplemented] format string parsing more robust #122402

Make #[diagnostic::on_unimplemented] format string parsing more robust #122402

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apiraino commented Mar 24, 2024 • edited

Make `#[diagnostic::on_unimplemented]` format string parsing more robust #122402

Make `#[diagnostic::on_unimplemented]` format string parsing more robust #122402

apiraino commented Mar 24, 2024 •

edited