diff --git a/RULES_DESCRIPTIONS.md b/RULES_DESCRIPTIONS.md index 65cbd61b1..3051d29f4 100644 --- a/RULES_DESCRIPTIONS.md +++ b/RULES_DESCRIPTIONS.md @@ -186,7 +186,16 @@ _Configuration_: N/A _Description_: By [convention](https://github.com/golang/go/wiki/CodeReviewComments#contexts), `context.Context` should be the first parameter of a function. This rule spots function declarations that do not follow the convention. -_Configuration_: N/A +_Configuration_: + +* `allowTypesBefore` : (string) comma-separated list of types that may be before 'context.Context' + +Example: + +```toml +[rule.context-as-argument] + arguments = [{allowTypesBefore = "*testing.T,*github.com/user/repo/testing.Harness"}] +``` ## context-keys-type @@ -252,7 +261,7 @@ _Configuration_: N/A _Description_: In GO it is idiomatic to minimize nesting statements, a typical example is to avoid if-then-else constructions. This rule spots constructions like ```go if cond { - // do something + // do something } else { // do other thing return ... @@ -262,7 +271,7 @@ that can be rewritten into more idiomatic: ```go if ! cond { // do other thing - return ... + return ... } // do something @@ -314,8 +323,8 @@ _Description_: Exported function and methods should have comments. This warns on More information [here](https://github.com/golang/go/wiki/CodeReviewComments#doc-comments) -_Configuration_: ([]string) rule flags. -Please notice that without configuration, the default behavior of the rule is that of its `golint` counterpart. +_Configuration_: ([]string) rule flags. +Please notice that without configuration, the default behavior of the rule is that of its `golint` counterpart. Available flags are: * _checkPrivateReceivers_ enables checking public methods of private types @@ -425,8 +434,8 @@ Example: ``` ## import-shadowing -_Description_: In GO it is possible to declare identifiers (packages, structs, -interfaces, parameters, receivers, variables, constants...) that conflict with the +_Description_: In GO it is possible to declare identifiers (packages, structs, +interfaces, parameters, receivers, variables, constants...) that conflict with the name of an imported package. This rule spots identifiers that shadow an import. _Configuration_: N/A @@ -503,7 +512,7 @@ _Configuration_: N/A ## range-val-address -_Description_: Range variables in a loop are reused at each iteration. This rule warns when assigning the address of the variable, passing the address to append() or using it in a map. +_Description_: Range variables in a loop are reused at each iteration. This rule warns when assigning the address of the variable, passing the address to append() or using it in a map. _Configuration_: N/A @@ -521,7 +530,7 @@ Even if possible, redefining these built in names can lead to bugs very difficul _Configuration_: N/A ## string-of-int -_Description_: explicit type conversion `string(i)` where `i` has an integer type other than `rune` might behave not as expected by the developer (e.g. `string(42)` is not `"42"`). This rule spot that kind of suspicious conversions. +_Description_: explicit type conversion `string(i)` where `i` has an integer type other than `rune` might behave not as expected by the developer (e.g. `string(42)` is not `"42"`). This rule spot that kind of suspicious conversions. _Configuration_: N/A @@ -534,7 +543,7 @@ _Configuration_: Each argument is a slice containing 2-3 strings: a scope, a reg 1. The first string defines a scope. This controls which string literals the regex will apply to, and is defined as a function argument. It must contain at least a function name (`core.WriteError`). Scopes may optionally contain a number specifying which argument in the function to check (`core.WriteError[1]`), as well as a struct field (`core.WriteError[1].Message`, only works for top level fields). Function arguments are counted starting at 0, so `[0]` would refer to the first argument, `[1]` would refer to the second, etc. If no argument number is provided, the first argument will be used (same as `[0]`). -2. The second string is a regular expression (beginning and ending with a `/` character), which will be used to check the string literals in the scope. +2. The second string is a regular expression (beginning and ending with a `/` character), which will be used to check the string literals in the scope. 3. The third string (optional) is a message containing the purpose for the regex, which will be used in lint errors. @@ -649,8 +658,8 @@ _Configuration_: N/A ## useless-break -_Description_: This rule warns on useless `break` statements in case clauses of switch and select statements. GO, unlike other programming languages like C, only executes statements of the selected case while ignoring the subsequent case clauses. -Therefore, inserting a `break` at the end of a case clause has no effect. +_Description_: This rule warns on useless `break` statements in case clauses of switch and select statements. GO, unlike other programming languages like C, only executes statements of the selected case while ignoring the subsequent case clauses. +Therefore, inserting a `break` at the end of a case clause has no effect. Because `break` statements are rarely used in case clauses, when switch or select statements are inside a for-loop, the programmer might wrongly assume that a `break` in a case clause will take the control out of the loop. The rule emits a specific warning for such cases. diff --git a/rule/context-as-argument.go b/rule/context-as-argument.go index 6502a07be..481c11693 100644 --- a/rule/context-as-argument.go +++ b/rule/context-as-argument.go @@ -1,22 +1,49 @@ package rule import ( + "fmt" "go/ast" "github.com/mgechev/revive/lint" ) // ContextAsArgumentRule lints given else constructs. -type ContextAsArgumentRule struct{} +type ContextAsArgumentRule struct { +} // Apply applies the rule to given file. -func (r *ContextAsArgumentRule) Apply(file *lint.File, _ lint.Arguments) []lint.Failure { +func (r *ContextAsArgumentRule) Apply(file *lint.File, args lint.Arguments) []lint.Failure { + var allowTypesBefore []string + if len(args) > 1 { + panic(fmt.Sprintf("Invalid argument to the context-as-argument rule. Expecting a single k,v map only, got %v args", len(args))) + } + if len(args) == 1 { + argKV, ok := args[0].(map[string]interface{}) + if !ok { + panic(fmt.Sprintf("Invalid argument to the context-as-argument rule. Expecting a k,v map, got %T", args[0])) + } + for k, v := range argKV { + switch k { + case "allowTypesBefore": + typesBefore, ok := v.([]string) + if !ok { + panic(fmt.Sprintf("Invalid argument to the context-as-argument.allowTypesBefore rule. Expecting a []string, got %T", v)) + } + allowTypesBefore = typesBefore + default: + panic(fmt.Sprintf("Invalid argument to the context-as-argument rule. Unrecognized key %s", k)) + } + } + // validate there's no other unrecognized args + } + var failures []lint.Failure fileAst := file.AST walker := lintContextArguments{ - file: file, - fileAst: fileAst, + allowTypesBefore: allowTypesBefore, + file: file, + fileAst: fileAst, onFailure: func(failure lint.Failure) { failures = append(failures, failure) }, @@ -33,9 +60,10 @@ func (r *ContextAsArgumentRule) Name() string { } type lintContextArguments struct { - file *lint.File - fileAst *ast.File - onFailure func(lint.Failure) + file *lint.File + fileAst *ast.File + allowTypesBefore []string + onFailure func(lint.Failure) } func (w lintContextArguments) Visit(n ast.Node) ast.Visitor { @@ -43,10 +71,37 @@ func (w lintContextArguments) Visit(n ast.Node) ast.Visitor { if !ok || len(fn.Type.Params.List) <= 1 { return w } + allowTypesLookup := make(map[string]struct{}, len(w.allowTypesBefore)) + for _, v := range w.allowTypesBefore { + allowTypesLookup[v] = struct{}{} + } + + fnArgs := fn.Type.Params.List + // trim off all types we've been configured to skip + for len(fnArgs) > 0 { + typeStr, ok := astExprTypeStr(fnArgs[0].Type) + if !ok { + // assume we're done. This can happen, for example, with a function type + // argument (`func(x func()...)` which we choose not to represent. + break + } + _, isAllowed := allowTypesLookup[typeStr] + if isAllowed { + // trim + fnArgs = fnArgs[1:] + } else { + // first non-trimmed argument means we've trimmed all prefix args + break + } + } + + if len(fnArgs) <= 1 { + return w + } // A context.Context should be the first parameter of a function. // Flag any that show up after the first. - previousArgIsCtx := isPkgDot(fn.Type.Params.List[0].Type, "context", "Context") - for _, arg := range fn.Type.Params.List[1:] { + previousArgIsCtx := isPkgDot(fnArgs[0].Type, "context", "Context") + for _, arg := range fnArgs[1:] { argIsCtx := isPkgDot(arg.Type, "context", "Context") if argIsCtx && !previousArgIsCtx { w.onFailure(lint.Failure{ diff --git a/rule/utils.go b/rule/utils.go index 0d5744846..ec59a0210 100644 --- a/rule/utils.go +++ b/rule/utils.go @@ -66,6 +66,14 @@ func isCgoExported(f *ast.FuncDecl) bool { var allCapsRE = regexp.MustCompile(`^[A-Z0-9_]+$`) +func identStr(expr ast.Expr) (string, bool) { + id, ok := expr.(*ast.Ident) + if !ok { + return "", false + } + return id.Name, true +} + func isIdent(expr ast.Expr, ident string) bool { id, ok := expr.(*ast.Ident) return ok && id.Name == ident @@ -92,11 +100,42 @@ func validType(T types.Type) bool { !strings.Contains(T.String(), "invalid type") // good but not foolproof } +func astExprTypeStr(expr ast.Expr) (string, bool) { + switch v := expr.(type) { + case *ast.Ident: + return identStr(v) + case *ast.StarExpr: + subID, ok := astExprTypeStr(v.X) + if !ok { + return "", false + } + return "*" + subID, true + case *ast.SelectorExpr: + pkg, ok := identStr(v.X) + if !ok { + return "", false + } + sel, ok := identStr(v.Sel) + if !ok { + return "", false + } + return pkg + "." + sel, true + } + return "", false +} + +// isPkgDot checks if the expression is . func isPkgDot(expr ast.Expr, pkg, name string) bool { sel, ok := expr.(*ast.SelectorExpr) return ok && isIdent(sel.X, pkg) && isIdent(sel.Sel, name) } +// isPtrPkgDot checks if the expression is *.. +func isPtrPkgDot(expr ast.Expr, pkg, name string) bool { + star, ok := expr.(*ast.StarExpr) + return ok && isPkgDot(star.X, pkg, name) +} + func srcLine(src []byte, p token.Position) string { // Run to end of line in both directions if not at line start/end. lo, hi := p.Offset, p.Offset+1 diff --git a/test/context-as-argument_test.go b/test/context-as-argument_test.go new file mode 100644 index 000000000..c6e23d120 --- /dev/null +++ b/test/context-as-argument_test.go @@ -0,0 +1,23 @@ +package test + +import ( + "testing" + + "github.com/mgechev/revive/lint" + "github.com/mgechev/revive/rule" +) + +func TestContextAsArgument(t *testing.T) { + testRule(t, "context-as-argument", &rule.ContextAsArgumentRule{}, &lint.RuleConfig{ + Arguments: []interface{}{ + map[string]interface{}{ + "allowTypesBefore": []string{ + "AllowedBeforeType", + "AllowedBeforeStruct", + "*AllowedBeforePtrStruct", + "*testing.T", + }, + }, + }, + }) +} diff --git a/test/golint_test.go b/test/golint_test.go index 487218420..f443688e2 100644 --- a/test/golint_test.go +++ b/test/golint_test.go @@ -31,7 +31,6 @@ var rules = []lint.Rule{ &rule.UnexportedReturnRule{}, &rule.TimeNamingRule{}, &rule.ContextKeysType{}, - &rule.ContextAsArgumentRule{}, } func TestAll(t *testing.T) { diff --git a/testdata/golint/context-as-argument.go b/testdata/context-as-argument.go similarity index 50% rename from testdata/golint/context-as-argument.go rename to testdata/context-as-argument.go index 62e152c40..49f9c6119 100644 --- a/testdata/golint/context-as-argument.go +++ b/testdata/context-as-argument.go @@ -5,8 +5,18 @@ package foo import ( "context" + "testing" ) +// AllowedBeforeType is a type that is configured to be allowed before context.Context +type AllowedBeforeType string + +// AllowedBeforeStruct is a type that is configured to be allowed before context.Context +type AllowedBeforeStruct struct{} + +// AllowedBeforePtrStruct is a type that is configured to be allowed before context.Context +type AllowedBeforePtrStruct struct{} + // A proper context.Context location func x(ctx context.Context) { // ok } @@ -15,6 +25,22 @@ func x(ctx context.Context) { // ok func x(ctx context.Context, s string) { // ok } +// *testing.T is permitted in the linter config for the test +func x(t *testing.T, ctx context.Context) { // ok +} + +func x(_ AllowedBeforeType, _ AllowedBeforeType, ctx context.Context) { // ok +} + +func x(_, _ AllowedBeforeType, ctx context.Context) { // ok +} + +func x(_ *AllowedBeforePtrStruct, ctx context.Context) { // ok +} + +func x(_ AllowedBeforePtrStruct, ctx context.Context) { // MATCH /context.Context should be the first parameter of a function/ +} + // An invalid context.Context location func y(s string, ctx context.Context) { // MATCH /context.Context should be the first parameter of a function/ }