Auto merge of #9161 - Victor-N-Suadicani:move_format_push_string_to_pedantic, r=flip1995

Move format_push_string to restriction

Fixes #9077 (kinda) by moving the lint to the restriction group. As I noted in that issue, I think the suggested change is too much and as the OP of the issue points out, the ramifications of the change are not necessarily easily understood. As such I don't think the lint should be enabled by default.

changelog: [`format_push_string`]: moved to restriction (see #9077).

Author: bors

clippy_lints/src/format_push_string.rs

@@ -14,6 +14,12 @@ declare_clippy_lint! {
     /// ### Why is this bad?
     /// Introduces an extra, avoidable heap allocation.
     ///
+    /// ### Known problems
+    /// `format!` returns a `String` but `write!` returns a `Result`.
+    /// Thus you are forced to ignore the `Err` variant to achieve the same API.
+    ///
+    /// While using `write!` in the suggested way should never fail, this isn't necessarily clear to the programmer.
+    ///
     /// ### Example
     /// ```rust
     /// let mut s = String::new();
@@ -29,7 +35,7 @@ declare_clippy_lint! {
     /// ```
     #[clippy::version = "1.62.0"]
     pub FORMAT_PUSH_STRING,
-    perf,
+    restriction,
     "`format!(..)` appended to existing `String`"
 }
 declare_lint_pass!(FormatPushString => [FORMAT_PUSH_STRING]);

clippy_lints/src/lib.register_all.rs

@@ -71,7 +71,6 @@ store.register_group(true, "clippy::all", Some("clippy_all"), vec![
     LintId::of(format_args::TO_STRING_IN_FORMAT_ARGS),
     LintId::of(format_impl::PRINT_IN_FORMAT_IMPL),
     LintId::of(format_impl::RECURSIVE_FORMAT_IMPL),
-    LintId::of(format_push_string::FORMAT_PUSH_STRING),
     LintId::of(formatting::POSSIBLE_MISSING_COMMA),
     LintId::of(formatting::SUSPICIOUS_ASSIGNMENT_FORMATTING),
     LintId::of(formatting::SUSPICIOUS_ELSE_FORMATTING),

clippy_lints/src/lib.register_perf.rs

@@ -7,7 +7,6 @@ store.register_group(true, "clippy::perf", Some("clippy_perf"), vec![
     LintId::of(escape::BOXED_LOCAL),
     LintId::of(format_args::FORMAT_IN_FORMAT_ARGS),
     LintId::of(format_args::TO_STRING_IN_FORMAT_ARGS),
-    LintId::of(format_push_string::FORMAT_PUSH_STRING),
     LintId::of(large_const_arrays::LARGE_CONST_ARRAYS),
     LintId::of(large_enum_variant::LARGE_ENUM_VARIANT),
     LintId::of(loops::MANUAL_MEMCPY),

clippy_lints/src/lib.register_restriction.rs

@@ -21,6 +21,7 @@ store.register_group(true, "clippy::restriction", Some("clippy_restriction"), ve
     LintId::of(exhaustive_items::EXHAUSTIVE_STRUCTS),
     LintId::of(exit::EXIT),
     LintId::of(float_literal::LOSSY_FLOAT_LITERAL),
+    LintId::of(format_push_string::FORMAT_PUSH_STRING),
     LintId::of(if_then_some_else_none::IF_THEN_SOME_ELSE_NONE),
     LintId::of(implicit_return::IMPLICIT_RETURN),
     LintId::of(indexing_slicing::INDEXING_SLICING),