refactor: redundant_test_prefix make suffix configurable

Author: farazdagi

CHANGELOG.md

@@ -6461,4 +6461,5 @@ Released 2018-09-13
 [`warn-on-all-wildcard-imports`]: https://doc.rust-lang.org/clippy/lint_configuration.html#warn-on-all-wildcard-imports
 [`warn-unsafe-macro-metavars-in-private-macros`]: https://doc.rust-lang.org/clippy/lint_configuration.html#warn-unsafe-macro-metavars-in-private-macros
 [`redundant-test-prefix-in-integration-tests`]: https://doc.rust-lang.org/clippy/lint_configuration.html#redundant-test-prefix-in-integration-tests
+[`redundant-test-prefix-custom-suffix`]: https://doc.rust-lang.org/clippy/lint_configuration.html#redundant-test-prefix-custom-suffix
 <!-- end autogenerated links to configuration documentation -->

book/src/lint_configuration.md

@@ -1098,3 +1098,17 @@ Whether to include integration tests in the linting process or not.
 ---
 **Affected lints:**
 * [`redundant_test_prefix`](https://rust-lang.github.io/rust-clippy/master/index.html#redundant_test_prefix)
+
+
+## `redundant-test-prefix-custom-suffix`
+What suffix to use to avoid function name collisions when `test_` prefix is removed.
+
+If set to `"_works"`, the lint will suggest renaming `test_foo` to `foo_works`.
+Suffix is added only when there is a collision with an existing function name,
+otherwise just `test_` prefix is removed (and no suffix added).
+
+**Default Value:** `"_works"`
+
+---
+**Affected lints:**
+* [`redundant_test_prefix`](https://rust-lang.github.io/rust-clippy/master/index.html#redundant_test_prefix)

clippy_config/src/conf.rs

@@ -849,6 +849,13 @@ define_Conf! {
     /// Whether to include integration tests in the linting process or not.
     #[lints(redundant_test_prefix)]
     redundant_test_prefix_in_integration_tests: bool = false,
+    /// What suffix to use to avoid function name collisions when `test_` prefix is removed.
+    ///
+    /// If set to `"_works"`, the lint will suggest renaming `test_foo` to `foo_works`.
+    /// Suffix is added only when there is a collision with an existing function name,
+    /// otherwise just `test_` prefix is removed (and no suffix added).
+    #[lints(redundant_test_prefix)]
+    redundant_test_prefix_custom_suffix: String = String::from("_works"),
 }
 
 /// Search for the configuration file.

clippy_lints/src/redundant_test_prefix.rs

@@ -43,12 +43,14 @@ declare_clippy_lint! {
 
 pub struct RedundantTestPrefix {
     in_integration_tests: bool,
+    custom_sufix: String,
 }
 
 impl RedundantTestPrefix {
     pub fn new(conf: &'static Conf) -> Self {
         Self {
             in_integration_tests: conf.redundant_test_prefix_in_integration_tests,
+            custom_sufix: conf.redundant_test_prefix_custom_suffix.clone(),
         }
     }
 }
@@ -83,7 +85,7 @@ impl<'tcx> LateLintPass<'tcx> for RedundantTestPrefix {
             // If `non_prefixed` conflicts with another function in the same module/scope,
             // add extra suffix to avoid name conflict.
             if name_conflicts(cx, body, &non_prefixed) {
-                non_prefixed.push_str("_works");
+                non_prefixed.push_str(&self.custom_sufix);
                 help_msg = "consider removing the `test_` prefix (suffix avoids name conflict)";
             }
             span_lint_and_sugg(

tests/ui-toml/redundant_test_prefix/custom_suffix_tests/clippy.toml

@@ -0,0 +1,2 @@
+redundant-test-prefix-custom-suffix = "_ok"
+redundant-test-prefix-in-integration-tests = true

tests/ui-toml/redundant_test_prefix/redundant_test_prefix.default.fixed

@@ -0,0 +1,55 @@
+//@revisions: default integ_tests suffix_tests
+//@[default] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/redundant_test_prefix/default
+//@[integ_tests] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/redundant_test_prefix/in_integration_tests
+//@[suffix_tests] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/redundant_test_prefix/custom_suffix_tests
+//@compile-flags: --test
+#![allow(dead_code)]
+#![warn(clippy::redundant_test_prefix)]
+
+fn main() {}
+
+mod tests_no_annotations {
+    use super::*;
+
+    #[test]
+    fn test_has_annotation() {
+        //~[integ_tests]^ redundant_test_prefix
+    }
+
+    fn no_annotation() {}
+}
+
+#[test]
+fn test_main_module_has_annotation() {
+    //~[integ_tests]^ redundant_test_prefix
+}
+
+fn test_main_module_no_annotation() {}
+
+fn foo() {}
+
+#[cfg(test)]
+#[test]
+fn foo_works() {
+    //~^ ERROR: redundant `test_` prefix in test function name
+    //~| HELP: consider removing the `test_` prefix (suffix avoids name conflict)
+
+    todo!()
+    // Has prefix, has `#[test]` attribute, within a `#[cfg(test)]`.
+    // Collision with existing function, so suffix is added.
+}
+
+fn bar() {}
+
+#[test]
+fn test_bar() {
+    //~[suffix_tests]^ redundant_test_prefix
+
+    todo!()
+    // Has prefix, has `#[test]` attribute.
+    // NOT within a `#[cfg(test)]`, but the lint is enabled for integration tests.
+    // Collision with existing function, so suffix is added.
+}
+
+#[cfg(test)]
+mod tests {}

tests/ui-toml/redundant_test_prefix/redundant_test_prefix.default.stderr

@@ -0,0 +1,11 @@
+error: redundant `test_` prefix in test function name
+  --> tests/ui-toml/redundant_test_prefix/redundant_test_prefix.rs:33:4
+   |
+LL | fn test_foo() {
+   |    ^^^^^^^^ help: consider removing the `test_` prefix (suffix avoids name conflict): `foo_works`
+   |
+   = note: `-D clippy::redundant-test-prefix` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::redundant_test_prefix)]`
+
+error: aborting due to 1 previous error
+

tests/ui-toml/redundant_test_prefix/redundant_test_prefix.integ_tests.fixed

@@ -1,6 +1,7 @@
-//@revisions: default integ_tests
+//@revisions: default integ_tests suffix_tests
 //@[default] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/redundant_test_prefix/default
 //@[integ_tests] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/redundant_test_prefix/in_integration_tests
+//@[suffix_tests] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/redundant_test_prefix/custom_suffix_tests
 //@compile-flags: --test
 #![allow(dead_code)]
 #![warn(clippy::redundant_test_prefix)]
@@ -25,5 +26,30 @@ fn main_module_has_annotation() {
 
 fn test_main_module_no_annotation() {}
 
+fn foo() {}
+
+#[cfg(test)]
+#[test]
+fn foo_works() {
+    //~^ ERROR: redundant `test_` prefix in test function name
+    //~| HELP: consider removing the `test_` prefix (suffix avoids name conflict)
+
+    todo!()
+    // Has prefix, has `#[test]` attribute, within a `#[cfg(test)]`.
+    // Collision with existing function, so suffix is added.
+}
+
+fn bar() {}
+
+#[test]
+fn bar_works() {
+    //~[suffix_tests]^ redundant_test_prefix
+
+    todo!()
+    // Has prefix, has `#[test]` attribute.
+    // NOT within a `#[cfg(test)]`, but the lint is enabled for integration tests.
+    // Collision with existing function, so suffix is added.
+}
+
 #[cfg(test)]
 mod tests {}

tests/ui-toml/redundant_test_prefix/redundant_test_prefix.integ_tests.stderr

@@ -1,5 +1,5 @@
 error: redundant `test_` prefix in test function name
-  --> tests/ui-toml/redundant_test_prefix/redundant_test_prefix.rs:14:8
+  --> tests/ui-toml/redundant_test_prefix/redundant_test_prefix.rs:15:8
    |
 LL |     fn test_has_annotation() {
    |        ^^^^^^^^^^^^^^^^^^^ help: consider removing the `test_` prefix: `has_annotation`
@@ -8,10 +8,22 @@ LL |     fn test_has_annotation() {
    = help: to override `-D warnings` add `#[allow(clippy::redundant_test_prefix)]`
 
 error: redundant `test_` prefix in test function name
-  --> tests/ui-toml/redundant_test_prefix/redundant_test_prefix.rs:22:4
+  --> tests/ui-toml/redundant_test_prefix/redundant_test_prefix.rs:23:4
    |
 LL | fn test_main_module_has_annotation() {
    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: consider removing the `test_` prefix: `main_module_has_annotation`
 
-error: aborting due to 2 previous errors
+error: redundant `test_` prefix in test function name
+  --> tests/ui-toml/redundant_test_prefix/redundant_test_prefix.rs:33:4
+   |
+LL | fn test_foo() {
+   |    ^^^^^^^^ help: consider removing the `test_` prefix (suffix avoids name conflict): `foo_works`
+
+error: redundant `test_` prefix in test function name
+  --> tests/ui-toml/redundant_test_prefix/redundant_test_prefix.rs:45:4
+   |
+LL | fn test_bar() {
+   |    ^^^^^^^^ help: consider removing the `test_` prefix (suffix avoids name conflict): `bar_works`
+
+error: aborting due to 4 previous errors
 

tests/ui-toml/redundant_test_prefix/redundant_test_prefix.rs

@@ -1,6 +1,7 @@
-//@revisions: default integ_tests
+//@revisions: default integ_tests suffix_tests
 //@[default] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/redundant_test_prefix/default
 //@[integ_tests] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/redundant_test_prefix/in_integration_tests
+//@[suffix_tests] rustc-env:CLIPPY_CONF_DIR=tests/ui-toml/redundant_test_prefix/custom_suffix_tests
 //@compile-flags: --test
 #![allow(dead_code)]
 #![warn(clippy::redundant_test_prefix)]
@@ -25,5 +26,30 @@ fn test_main_module_has_annotation() {
 
 fn test_main_module_no_annotation() {}
 
+fn foo() {}
+
+#[cfg(test)]
+#[test]
+fn test_foo() {
+    //~^ ERROR: redundant `test_` prefix in test function name
+    //~| HELP: consider removing the `test_` prefix (suffix avoids name conflict)
+
+    todo!()
+    // Has prefix, has `#[test]` attribute, within a `#[cfg(test)]`.
+    // Collision with existing function, so suffix is added.
+}
+
+fn bar() {}
+
+#[test]
+fn test_bar() {
+    //~[suffix_tests]^ redundant_test_prefix
+
+    todo!()
+    // Has prefix, has `#[test]` attribute.
+    // NOT within a `#[cfg(test)]`, but the lint is enabled for integration tests.
+    // Collision with existing function, so suffix is added.
+}
+
 #[cfg(test)]
 mod tests {}