From fa0df69a979e490b639a9f502f95060649ba5fb9 Mon Sep 17 00:00:00 2001
From: Georg Brandl <georg@python.org>
Date: Sat, 6 Aug 2016 20:59:27 +0200
Subject: [PATCH] Add a configurable threshold for enum variants before name
 lints trigger (fixes #1138)

---
 clippy_lints/src/enum_variants.rs   | 19 ++++++++++++------
 clippy_lints/src/lib.rs             |  2 +-
 clippy_lints/src/utils/conf.rs      |  2 ++
 tests/compile-fail/enum_variants.rs | 30 +++++++++++++++++++----------
 4 files changed, 36 insertions(+), 17 deletions(-)

diff --git a/clippy_lints/src/enum_variants.rs b/clippy_lints/src/enum_variants.rs
index 8278780d9b4..03bd49b09b6 100644
--- a/clippy_lints/src/enum_variants.rs
+++ b/clippy_lints/src/enum_variants.rs
@@ -44,9 +44,15 @@ declare_lint! {
     "finds type names prefixed/postfixed with their containing module's name"
 }
 
-#[derive(Default)]
 pub struct EnumVariantNames {
     modules: Vec<String>,
+    threshold: u64,
+}
+
+impl EnumVariantNames {
+    pub fn new(threshold: u64) -> EnumVariantNames {
+        EnumVariantNames { modules: Vec::new(), threshold: threshold }
+    }
 }
 
 impl LintPass for EnumVariantNames {
@@ -75,7 +81,11 @@ fn partial_rmatch(post: &str, name: &str) -> usize {
 
 // FIXME: #600
 #[allow(while_let_on_iterator)]
-fn check_variant(cx: &EarlyContext, def: &EnumDef, item_name: &str, item_name_chars: usize, span: Span) {
+fn check_variant(cx: &EarlyContext, threshold: u64, def: &EnumDef, item_name: &str,
+                 item_name_chars: usize, span: Span) {
+    if (def.variants.len() as u64) < threshold {
+        return;
+    }
     for var in &def.variants {
         let name = var2str(var);
         if partial_match(item_name, &name) == item_name_chars {
@@ -85,9 +95,6 @@ fn check_variant(cx: &EarlyContext, def: &EnumDef, item_name: &str, item_name_ch
             span_lint(cx, ENUM_VARIANT_NAMES, var.span, "Variant name ends with the enum's name");
         }
     }
-    if def.variants.len() < 2 {
-        return;
-    }
     let first = var2str(&def.variants[0]);
     let mut pre = &first[..camel_case_until(&*first)];
     let mut post = &first[camel_case_from(&*first)..];
@@ -177,7 +184,7 @@ impl EarlyLintPass for EnumVariantNames {
             }
         }
         if let ItemKind::Enum(ref def, _) = item.node {
-            check_variant(cx, def, &item_name, item_name_chars, item.span);
+            check_variant(cx, self.threshold, def, &item_name, item_name_chars, item.span);
         }
         self.modules.push(item_camel);
     }
diff --git a/clippy_lints/src/lib.rs b/clippy_lints/src/lib.rs
index 7308a656590..f110bb8f329 100644
--- a/clippy_lints/src/lib.rs
+++ b/clippy_lints/src/lib.rs
@@ -175,7 +175,7 @@ pub fn register_plugins(reg: &mut rustc_plugin::Registry) {
     reg.register_late_lint_pass(box misc::TopLevelRefPass);
     reg.register_late_lint_pass(box misc::CmpNan);
     reg.register_late_lint_pass(box eq_op::EqOp);
-    reg.register_early_lint_pass(box enum_variants::EnumVariantNames::default());
+    reg.register_early_lint_pass(box enum_variants::EnumVariantNames::new(conf.enum_variant_name_threshold));
     reg.register_late_lint_pass(box enum_glob_use::EnumGlobUse);
     reg.register_late_lint_pass(box enum_clike::UnportableVariant);
     reg.register_late_lint_pass(box bit_mask::BitMask);
diff --git a/clippy_lints/src/utils/conf.rs b/clippy_lints/src/utils/conf.rs
index edb18478c3f..07be9f7f5bc 100644
--- a/clippy_lints/src/utils/conf.rs
+++ b/clippy_lints/src/utils/conf.rs
@@ -160,6 +160,8 @@ define_Conf! {
     ("single-char-binding-names-threshold", max_single_char_names, 5 => u64),
     /// Lint: BOXED_LOCAL. The maximum size of objects (in bytes) that will be linted. Larger objects are ok on the heap
     ("too-large-for-stack", too_large_for_stack, 200 => u64),
+    /// Lint: ENUM_VARIANT_NAMES. The minimum number of enum variants for the lints about variant names to trigger
+    ("enum-variant-name-threshold", enum_variant_name_threshold, 3 => u64),
 }
 
 /// Read the `toml` configuration file. The function will ignore “File not found” errors iif
diff --git a/tests/compile-fail/enum_variants.rs b/tests/compile-fail/enum_variants.rs
index ed7f7823f8f..f0fda37f7f8 100644
--- a/tests/compile-fail/enum_variants.rs
+++ b/tests/compile-fail/enum_variants.rs
@@ -13,6 +13,22 @@ enum FakeCallType2 {
 enum Foo {
     cFoo, //~ ERROR: Variant name ends with the enum's name
     cBar,
+    cBaz,
+}
+
+enum Fooo {
+    cFoo, // no error, threshold is 3 variants by default
+    cBar,
+}
+
+enum Food { //~ ERROR: All variants have the same prefix: `Food`
+    FoodGood, //~ ERROR: Variant name starts with the enum's name
+    FoodMiddle, //~ ERROR: Variant name starts with the enum's name
+    FoodBad, //~ ERROR: Variant name starts with the enum's name
+}
+
+enum Stuff {
+    StuffBad, // no error
 }
 
 enum BadCallType { //~ ERROR: All variants have the same prefix: `CallType`
@@ -21,7 +37,7 @@ enum BadCallType { //~ ERROR: All variants have the same prefix: `CallType`
     CallTypeDestroy,
 }
 
-enum TwoCallType { //~ ERROR: All variants have the same prefix: `CallType`
+enum TwoCallType { // no error
     CallTypeCall,
     CallTypeCreate,
 }
@@ -32,7 +48,7 @@ enum Consts { //~ ERROR: All variants have the same prefix: `Constant`
     ConstantLie,
 }
 
-enum Two { //~ ERROR: All variants have the same prefix: `Constant`
+enum Two { // no error here
     ConstantInt,
     ConstantInfer,
 }
@@ -61,20 +77,14 @@ enum Sealll {
 
 enum Seallll { //~ ERROR: All variants have the same prefix: `With`
     WithOutCake,
+    WithOutTea,
     WithOut,
 }
 
 enum NonCaps { //~ ERROR: All variants have the same prefix: `Prefix`
     Prefix的,
+    PrefixTea,
     PrefixCake,
 }
 
-enum Stuff {
-    BadStuff, //~ ERROR: Variant name ends with the enum's name
-}
-
-enum Food {
-    FoodGood, //~ ERROR: Variant name starts with the enum's name
-}
-
 fn main() {}