fix(forge lint): do not flag fn test* and fn invariant* (#10607)

* fix: do not flag `fn test*` and `fn invariant*`

* fix: ignore `fn statefulFuzz*`

* test: ensure disabled

* test: expand unit tests

Co-authored-by: zerosnacks <[email protected]>

* fix: wildcard on `invariant_` rather than `invariant`

---------

Co-authored-by: zerosnacks <[email protected]>

Author: 0xrusowsky

crates/lint/src/sol/info/mixed_case.rs

@@ -19,7 +19,7 @@ impl<'ast> EarlyLintPass<'ast> for MixedCaseFunction {
     fn check_item_function(&mut self, ctx: &LintContext<'_>, func: &'ast ItemFunction<'ast>) {
         if let Some(name) = func.header.name {
             let name = name.as_str();
-            if !is_mixed_case(name) && name.len() > 1 {
+            if !is_mixed_case(name, true) {
                 ctx.emit(&MIXED_CASE_FUNCTION, func.body_span);
             }
         }
@@ -42,7 +42,7 @@ impl<'ast> EarlyLintPass<'ast> for MixedCaseVariable {
         if var.mutability.is_none() {
             if let Some(name) = var.name {
                 let name = name.as_str();
-                if !is_mixed_case(name) {
+                if !is_mixed_case(name, false) {
                     ctx.emit(&MIXED_CASE_VARIABLE, var.span);
                 }
             }
@@ -54,11 +54,17 @@ impl<'ast> EarlyLintPass<'ast> for MixedCaseVariable {
 ///
 /// To avoid false positives like `fn increment()` or `uint256 counter`,
 /// lowercase strings are treated as mixedCase.
-pub fn is_mixed_case(s: &str) -> bool {
+pub fn is_mixed_case(s: &str, is_fn: bool) -> bool {
     if s.len() <= 1 {
         return true;
     }
 
     // Remove leading/trailing underscores like `heck` does
-    s.trim_matches('_') == format!("{}", heck::AsLowerCamelCase(s)).as_str()
+    if s.trim_matches('_') == format!("{}", heck::AsLowerCamelCase(s)).as_str() {
+        return true
+    }
+
+    // Ignore `fn test*`, `fn invariant_*`, and `fn statefulFuzz*` patterns, as they usually contain
+    // (allowed) underscores.
+    is_fn && (s.starts_with("test") || s.starts_with("invariant_") || s.starts_with("statefulFuzz"))
 }

crates/lint/testdata/MixedCase.sol

@@ -26,4 +26,37 @@ contract MixedCaseTest {
     function Functionmixedcase() public {} //~NOTE: function names should use mixedCase
     function FUNCTION_MIXED_CASE() public {} //~NOTE: function names should use mixedCase
     function FunctionMixedCase() public {} //~NOTE: function names should use mixedCase
+    function function_mixed_case() public {} //~NOTE: function names should use mixedCase
+
+    // mixedCase checks are disabled for functions that starting with:
+    // `test`, `invariant_`, and `statefulFuzz`
+    function test_MixedCase_Disabled() public {}
+    function test_mixedcase_disabled() public {}
+    function testMixedCaseDisabled() public {}
+    function testmixedcasedisabled() public {}
+
+    function testFuzz_MixedCase_Disabled() public {}
+    function testFuzz_mixedcase_disabled() public {}
+    function testFuzzMixedCaseDisabled() public {}
+    function testfuzzmixedcasedisabled() public {}
+
+    function testRevert_MixedCase_Disabled() public {}
+    function testRevert_mixedcase_disabled() public {}
+    function testRevertMixedCaseDisabled() public {}
+    function testrevertmixedcasedisabled() public {}
+
+    function invariant_MixedCase_Disabled() public {}
+    function invariant_mixedcase_disabled() public {}
+    function invariant_MixedCaseDisabled() public {}
+    function invariant_mixedcasedisabled() public {}
+
+    function invariantBalance_MixedCase_Enabled() public {} //~NOTE: function names should use mixedCase
+    function invariantbalance_mixedcase_enabled() public {} //~NOTE: function names should use mixedCase
+    function invariantBalanceMixedCaseEnabled() public {}
+    function invariantbalancemixedcaseenabled() public {}
+
+    function statefulFuzz_MixedCase_Disabled() public {}
+    function statefulFuzz_mixedcase_disabled() public {}
+    function statefulFuzzMixedCaseDisabled() public {}
+    function statefulFuzzmixedcasedisabled() public {}
 }

crates/lint/testdata/MixedCase.stderr

@@ -64,3 +64,27 @@ note[mixed-case-function]: function names should use mixedCase
    |
    = help: https://docs.soliditylang.org/en/latest/style-guide.html#function-names
 
+note[mixed-case-function]: function names should use mixedCase
+  --> ROOT/testdata/MixedCase.sol:LL:CC
+   |
+29 |     function function_mixed_case() public {}
+   |                                           --
+   |
+   = help: https://docs.soliditylang.org/en/latest/style-guide.html#function-names
+
+note[mixed-case-function]: function names should use mixedCase
+  --> ROOT/testdata/MixedCase.sol:LL:CC
+   |
+53 |     function invariantBalance_MixedCase_Enabled() public {}
+   |                                                          --
+   |
+   = help: https://docs.soliditylang.org/en/latest/style-guide.html#function-names
+
+note[mixed-case-function]: function names should use mixedCase
+  --> ROOT/testdata/MixedCase.sol:LL:CC
+   |
+54 |     function invariantbalance_mixedcase_enabled() public {}
+   |                                                          --
+   |
+   = help: https://docs.soliditylang.org/en/latest/style-guide.html#function-names
+