Clippy lint · Restriction · checked with Clippy 0.1.99

clippy::filetype_is_file: Checks for FileType::is_file()

What it meansChecks for FileType::is_file(). It is in the restriction group and off by default.

Does it matter?

When people testing a file type with FileType::is_file they are testing whether a path is something they can get bytes from. But is_file doesn’t cover special file types in unix-like systems, and doesn’t cover symlink in windows. Using !FileType::is_dir() is a better way to that intention.

Lints that forbid language features for specific codebases (no unwrap, no indexing...). Off by default; pick them one by one, never the whole group.

How to fix it

Clippy does not fix this one automatically. Change the code by hand:

Flagged

let metadata = std::fs::metadata("foo.txt")?;
let filetype = metadata.file_type();

if filetype.is_file() {
    // read file
}

Write this instead

let metadata = std::fs::metadata("foo.txt")?;
let filetype = metadata.file_type();

if !filetype.is_dir() {
    // read file
}

Turn it off, or on

It is off by default. To use it, set it to warn or deny:

Whole crate (Cargo.toml)

[lints.clippy]
filetype_is_file = "warn"

In code

#![warn(clippy::filetype_is_file)]

One run

cargo clippy -- -W clippy::filetype-is-file

The [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.

Restrictiongroup

allowdefault level

nofixed by cargo clippy --fix

1.42.0added in Rust

Clippy's own documentation

What it does

Checks for FileType::is_file().

Why restrict this?

When people testing a file type with FileType::is_file they are testing whether a path is something they can get bytes from. But is_file doesn’t cover special file types in unix-like systems, and doesn’t cover symlink in windows. Using !FileType::is_dir() is a better way to that intention.

Example

let metadata = std::fs::metadata("foo.txt")?;
let filetype = metadata.file_type();

if filetype.is_file() {
    // read file
}

should be written as:

let metadata = std::fs::metadata("foo.txt")?;
let filetype = metadata.file_type();

if !filetype.is_dir() {
    // read file
}

From the Clippy lint list (0.1.99), part of the Rust project, MIT or Apache-2.0. Official entry.

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