Add a new lint to prevent create_dir from being used

CHANGELOG.md

@@ -1444,6 +1444,7 @@ Released 2018-09-13
 [`collapsible_if`]: https://rust-lang.github.io/rust-clippy/master/index.html#collapsible_if
 [`comparison_chain`]: https://rust-lang.github.io/rust-clippy/master/index.html#comparison_chain
 [`copy_iterator`]: https://rust-lang.github.io/rust-clippy/master/index.html#copy_iterator
+[`create_dir`]: https://rust-lang.github.io/rust-clippy/master/index.html#create_dir
 [`crosspointer_transmute`]: https://rust-lang.github.io/rust-clippy/master/index.html#crosspointer_transmute
 [`dbg_macro`]: https://rust-lang.github.io/rust-clippy/master/index.html#dbg_macro
 [`debug_assert_with_mut_call`]: https://rust-lang.github.io/rust-clippy/master/index.html#debug_assert_with_mut_call

clippy_lints/src/create_dir.rs

@@ -0,0 +1,50 @@
+use crate::utils::{match_qpath, snippet, span_lint_and_sugg};
+use if_chain::if_chain;
+use rustc_errors::Applicability;
+use rustc_hir::*;
+use rustc_lint::{LateContext, LateLintPass};
+use rustc_session::{declare_lint_pass, declare_tool_lint};
+
+declare_clippy_lint! {
+    /// **What it does:** Checks usage of `std::fs::create_dir` and suggest using `std::fs::create_dir_all` instead.
+    ///
+    /// **Why is this bad?** Sometimes `std::fs::crate_dir` is mistakenly chosen over `std::fs::create_dir_all`.
+    ///
+    /// **Known problems:** None.
+    ///
+    /// **Example:**
+    ///
+    /// ```rust
+    /// std::fs::create_dir("foo")
+    /// ```
+    /// Use instead:
+    /// ```rust
+    /// std::fs::create_dir_all("foo")
+    /// ```
+    pub CREATE_DIR,
+    restriction,
+    "calling `std::fs::create_dir` instead of `std::fs::create_dir_all`"
+}
+
+declare_lint_pass!(CreateDir => [CREATE_DIR]);
+
+impl LateLintPass<'_> for CreateDir {
+    fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
+        if_chain! {
+            if let ExprKind::Call(ref func, ref args) = expr.kind;
+            if let ExprKind::Path(ref path) = func.kind;
+            if match_qpath(path, &["std", "fs", "create_dir"]);
+            then {
+                span_lint_and_sugg(
+                    cx,
+                    CREATE_DIR,
+                    expr.span,
+                    "calling `std::fs::create_dir` where there may be a better way",
+                    "consider calling `std::fs::create_dir_all` instead",
+                    format!("std::fs::create_dir_all({})", snippet(cx, args[0].span, "..")),
+                    Applicability::MachineApplicable,
+                )
+            }
+        }
+    }
+}

clippy_lints/src/lib.rs

@@ -169,6 +169,7 @@ mod collapsible_if;
 mod comparison_chain;
 mod copies;
 mod copy_iterator;
+mod create_dir;
 mod dbg_macro;
 mod default_trait_access;
 mod dereference;
@@ -511,6 +512,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         &copies::MATCH_SAME_ARMS,
         &copies::SAME_FUNCTIONS_IN_IF_CONDITION,
         &copy_iterator::COPY_ITERATOR,
+        &create_dir::CREATE_DIR,
         &dbg_macro::DBG_MACRO,
         &default_trait_access::DEFAULT_TRAIT_ACCESS,
         &dereference::EXPLICIT_DEREF_METHODS,
@@ -1042,6 +1044,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
     store.register_early_pass(|| box items_after_statements::ItemsAfterStatements);
     store.register_early_pass(|| box precedence::Precedence);
     store.register_early_pass(|| box needless_continue::NeedlessContinue);
+    store.register_late_pass(|| box create_dir::CreateDir);
     store.register_early_pass(|| box needless_arbitrary_self_type::NeedlessArbitrarySelfType);
     store.register_early_pass(|| box redundant_static_lifetimes::RedundantStaticLifetimes);
     store.register_late_pass(|| box cargo_common_metadata::CargoCommonMetadata);
@@ -1104,6 +1107,7 @@ pub fn register_plugins(store: &mut rustc_lint::LintStore, sess: &Session, conf:
         LintId::of(&arithmetic::FLOAT_ARITHMETIC),
         LintId::of(&arithmetic::INTEGER_ARITHMETIC),
         LintId::of(&as_conversions::AS_CONVERSIONS),
+        LintId::of(&create_dir::CREATE_DIR),
         LintId::of(&dbg_macro::DBG_MACRO),
         LintId::of(&else_if_without_else::ELSE_IF_WITHOUT_ELSE),
         LintId::of(&exit::EXIT),

src/lintlist/mod.rs

@@ -290,6 +290,13 @@ pub static ref ALL_LINTS: Vec<Lint> = vec![
         deprecation: None,
         module: "copy_iterator",
     },
+    Lint {
+        name: "create_dir",
+        group: "restriction",
+        desc: "calling `std::fs::create_dir` instead of `std::fs::create_dir_all`",
+        deprecation: None,
+        module: "create_dir",
+    },
     Lint {
         name: "crosspointer_transmute",
         group: "complexity",

tests/ui/create_dir.fixed

@@ -0,0 +1,13 @@
+// run-rustfix
+#![allow(unused_must_use)]
+#![warn(clippy::create_dir)]
+
+fn not_create_dir() {}
+
+fn main() {
+    std::fs::create_dir_all("foo");
+    std::fs::create_dir_all("bar").unwrap();
+
+    not_create_dir();
+    std::fs::create_dir_all("foobar");
+}

tests/ui/create_dir.rs

@@ -0,0 +1,13 @@
+// run-rustfix
+#![allow(unused_must_use)]
+#![warn(clippy::create_dir)]
+
+fn not_create_dir() {}
+
+fn main() {
+    std::fs::create_dir("foo");
+    std::fs::create_dir("bar").unwrap();
+
+    not_create_dir();
+    std::fs::create_dir_all("foobar");
+}

tests/ui/create_dir.stderr

@@ -0,0 +1,16 @@
+error: calling `std::fs::create_dir` where there may be a better way
+  --> $DIR/create_dir.rs:8:5
+   |
+LL |     std::fs::create_dir("foo");
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `std::fs::create_dir_all` instead: `std::fs::create_dir_all("foo")`
+   |
+   = note: `-D clippy::create-dir` implied by `-D warnings`
+
+error: calling `std::fs::create_dir` where there may be a better way
+  --> $DIR/create_dir.rs:9:5
+   |
+LL |     std::fs::create_dir("bar").unwrap();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider calling `std::fs::create_dir_all` instead: `std::fs::create_dir_all("bar")`
+
+error: aborting due to 2 previous errors
+