alef 0.62.7

Opinionated polyglot binding generator for Rust libraries
Documentation 
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use super::super::FfiBackend;
use super::common::*;
use crate::core::backend::Backend;
use crate::core::ir::*;

/// The emitted `lib.rs`'s crate-level `#![allow(...)]` list was audited against a real
/// `cargo clippy --all-targets -- -D warnings` run over an emitted tree (see
/// `tests/generated_output_downstream_gate.rs`), removing entries that never fired. This
/// pins the ones removed so they cannot silently return -- if one of them becomes
/// load-bearing again, the fix belongs at the emitter or per-item allow, not here. ~keep
#[test]
fn crate_level_allow_list_does_not_carry_dead_entries() {
    let api = ApiSurface {
        crate_name: "sample_lib".to_string(),
        version: "0.1.0".to_string(),
        functions: vec![FunctionDef {
            name: "run".to_string(),
            rust_path: "sample_lib::run".to_string(),
            return_type: TypeRef::Unit,
            ..FunctionDef::default()
        }],
        ..ApiSurface::default()
    };
    let config = resolved_one(
        r#"
[workspace]
languages = ["ffi"]

[[crates]]
name = "sample-lib"
sources = ["src/lib.rs"]

[crates.ffi]
prefix = "sample"
"#,
    );

    let files = FfiBackend.generate_bindings(&api, &config).unwrap();
    let lib = files.iter().find(|file| file.path.ends_with("lib.rs")).unwrap();
    let header_end = lib.content.find("use std::ffi").unwrap_or(lib.content.len());
    let header = &lib.content[..header_end];

    assert!(
        !header.contains("missing_docs"),
        "missing_docs is allow-by-default under rustc and is never escalated by -D warnings \
         alone, so the crate-level allow was a no-op:\n{header}"
    );
    assert!(
        !header.contains("clippy::too_many_arguments"),
        "too_many_arguments already gets a per-item #[allow] at every site that can exceed \
         the threshold (free functions, len companions, method wrappers, constructors, field \
         accessors), so the crate-level copy was redundant:\n{header}"
    );
    assert!(
        !header.contains("clippy::useless_conversion"),
        "useless_conversion's only source is the Vec<u8>::from(..) polymorphic bytes \
         conversion in bytes_result_match.jinja, which now carries its own narrow \
         #[allow(clippy::useless_conversion)] at each of its four sites:\n{header}"
    );
    // `unnecessary_cast` fires only when a cast's source expression already has the exact
    // destination type. Every `as i32`/`as u32`/`as usize` this backend emits casts a `bool`
    // or a genuine `Named` enum field (see `ffi_visitor_context_enum_init.jinja`, reached only
    // when `context_c_type` (`gen_visitor/context.rs`) resolves the field to a real IR enum --
    // never when the field is already `TypeRef::Primitive(I32)`, which routes through the
    // cast-free passthrough template instead) or an integer of a different width
    // (`handle_registry.rs.jinja`'s `u64 -> usize`/`u64 -> u32`). None of those is ever the
    // same type as the cast target, so clippy can never see this as redundant. Verified against
    // a real `cargo clippy --all-targets -- -D warnings` run over the non-visitor emitted tree
    // (`tests/generated_output_downstream_gate.rs`'s fixture) and, for the enum-context site
    // specifically, over a real `alef generate` run with a configured trait bridge --
    // `gen_bindings::tests::visitor::test_visitor_callbacks_emit_enum_node_type_as_i32` pins
    // that this backend still reaches and emits that exact cast. ~keep
    assert!(
        !header.contains("clippy::unnecessary_cast"),
        "every cast this backend emits converts a bool or a Named enum to a different \
         primitive type, which clippy's same-type check can never flag as redundant:\n{header}"
    );
}

/// The paired positive: the narrow per-item allow this audit added actually reaches the
/// generated bytes-conversion call site.
#[test]
fn bytes_result_conversion_carries_its_own_narrow_useless_conversion_allow() {
    let api = ApiSurface {
        crate_name: "sample_lib".to_string(),
        version: "0.1.0".to_string(),
        functions: vec![FunctionDef {
            name: "render".to_string(),
            rust_path: "sample_lib::render".to_string(),
            return_type: TypeRef::Bytes,
            error_type: Some("String".to_string()),
            ..FunctionDef::default()
        }],
        ..ApiSurface::default()
    };
    let config = resolved_one(
        r#"
[workspace]
languages = ["ffi"]

[[crates]]
name = "sample-lib"
sources = ["src/lib.rs"]

[crates.ffi]
prefix = "sample"
"#,
    );

    let files = FfiBackend.generate_bindings(&api, &config).unwrap();
    let lib = files.iter().find(|file| file.path.ends_with("lib.rs")).unwrap();

    assert!(
        lib.content
            .contains("#[allow(clippy::useless_conversion)]\n            let buffer = Vec::<u8>::from(val)"),
        "the bytes-conversion call site must keep its own narrow allow now that the \
         crate-level one is gone:\n{}",
        lib.content
    );
}