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Diffstat (limited to 'vendor/github.com/alecthomas')
10 files changed, 688 insertions, 0 deletions
diff --git a/vendor/github.com/alecthomas/go-check-sumtype/.goreleaser.yml b/vendor/github.com/alecthomas/go-check-sumtype/.goreleaser.yml new file mode 100644 index 000000000..33bd03d06 --- /dev/null +++ b/vendor/github.com/alecthomas/go-check-sumtype/.goreleaser.yml @@ -0,0 +1,32 @@ +project_name: go-check-sumtype +release: + github: + owner: alecthomas + name: go-check-sumtype +env: + - CGO_ENABLED=0 +builds: +- goos: + - linux + - darwin + - windows + goarch: + - arm64 + - amd64 + - "386" + goarm: + - "6" + main: ./cmd/go-check-sumtype + binary: go-check-sumtype +archives: + - + format: tar.gz + name_template: '{{ .Binary }}-{{ .Version }}-{{ .Os }}-{{ .Arch }}{{ if .Arm }}v{{ + .Arm }}{{ end }}' + files: + - COPYING + - README* +snapshot: + name_template: SNAPSHOT-{{ .Commit }} +checksum: + name_template: '{{ .ProjectName }}-{{ .Version }}-checksums.txt' diff --git a/vendor/github.com/alecthomas/go-check-sumtype/COPYING b/vendor/github.com/alecthomas/go-check-sumtype/COPYING new file mode 100644 index 000000000..bb9c20a09 --- /dev/null +++ b/vendor/github.com/alecthomas/go-check-sumtype/COPYING @@ -0,0 +1,3 @@ +This project is dual-licensed under the Unlicense and MIT licenses. + +You may use this code under the terms of either license. diff --git a/vendor/github.com/alecthomas/go-check-sumtype/LICENSE-MIT b/vendor/github.com/alecthomas/go-check-sumtype/LICENSE-MIT new file mode 100644 index 000000000..3b0a5dc09 --- /dev/null +++ b/vendor/github.com/alecthomas/go-check-sumtype/LICENSE-MIT @@ -0,0 +1,21 @@ +The MIT License (MIT) + +Copyright (c) 2015 Andrew Gallant + +Permission is hereby granted, free of charge, to any person obtaining a copy +of this software and associated documentation files (the "Software"), to deal +in the Software without restriction, including without limitation the rights +to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +copies of the Software, and to permit persons to whom the Software is +furnished to do so, subject to the following conditions: + +The above copyright notice and this permission notice shall be included in +all copies or substantial portions of the Software. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +THE SOFTWARE. diff --git a/vendor/github.com/alecthomas/go-check-sumtype/README.md b/vendor/github.com/alecthomas/go-check-sumtype/README.md new file mode 100644 index 000000000..36614ef40 --- /dev/null +++ b/vendor/github.com/alecthomas/go-check-sumtype/README.md @@ -0,0 +1,120 @@ +**Note: This is a fork of the great project [go-sumtype](https://github.com/BurntSushi/go-sumtype) by BurntSushi.** +**The original seems largely unmaintained, and the changes in this fork are backwards incompatible.** + +# go-check-sumtype [](https://github.com/alecthomas/go-check-sumtype/actions/workflows/ci.yml) +A simple utility for running exhaustiveness checks on type switch statements. +Exhaustiveness checks are only run on interfaces that are declared to be +"sum types." + +Dual-licensed under MIT or the [UNLICENSE](http://unlicense.org). + +This work was inspired by our code at +[Diffeo](https://diffeo.com). + +## Installation + +```go +$ go get github.com/alecthomas/go-check-sumtype +``` + +For usage info, just run the command: + +``` +$ go-check-sumtype +``` + +Typical usage might look like this: + +``` +$ go-check-sumtype $(go list ./... | grep -v vendor) +``` + +## Usage + +`go-check-sumtype` takes a list of Go package paths or files and looks for sum type +declarations in each package/file provided. Exhaustiveness checks are then +performed for each use of a declared sum type in a type switch statement. +Namely, `go-check-sumtype` will report an error for any type switch statement that +either lacks a `default` clause or does not account for all possible variants. + +Declarations are provided in comments like so: + +``` +//sumtype:decl +type MySumType interface { ... } +``` + +`MySumType` must be *sealed*. That is, part of its interface definition +contains an unexported method. + +`go-check-sumtype` will produce an error if any of the above is not true. + +For valid declarations, `go-check-sumtype` will look for all occurrences in which a +value of type `MySumType` participates in a type switch statement. In those +occurrences, it will attempt to detect whether the type switch is exhaustive +or not. If it's not, `go-check-sumtype` will report an error. For example, running +`go-check-sumtype` on this source file: + +```go +package main + +//sumtype:decl +type MySumType interface { + sealed() +} + +type VariantA struct{} + +func (*VariantA) sealed() {} + +type VariantB struct{} + +func (*VariantB) sealed() {} + +func main() { + switch MySumType(nil).(type) { + case *VariantA: + } +} +``` + +produces the following: + +``` +$ sumtype mysumtype.go +mysumtype.go:18:2: exhaustiveness check failed for sum type 'MySumType': missing cases for VariantB +``` + +Adding either a `default` clause or a clause to handle `*VariantB` will cause +exhaustive checks to pass. + +As a special case, if the type switch statement contains a `default` clause +that always panics, then exhaustiveness checks are still performed. + +## Details and motivation + +Sum types are otherwise known as discriminated unions. That is, a sum type is +a finite set of disjoint values. In type systems that support sum types, the +language will guarantee that if one has a sum type `T`, then its value must +be one of its variants. + +Go's type system does not support sum types. A typical proxy for representing +sum types in Go is to use an interface with an unexported method and define +each variant of the sum type in the same package to satisfy said interface. +This guarantees that the set of types that satisfy the interface is closed +at compile time. Performing case analysis on these types is then done with +a type switch statement, e.g., `switch x.(type) { ... }`. Each clause of the +type switch corresponds to a *variant* of the sum type. The downside of this +approach is that Go's type system is not aware of the set of variants, so it +cannot tell you whether case analysis over a sum type is complete or not. + +The `go-check-sumtype` command recognizes this pattern, but it needs a small amount +of help to recognize which interfaces should be treated as sum types, which +is why the `//sumtype:decl` annotation is required. `go-check-sumtype` will +figure out all of the variants of a sum type by finding the set of types +defined in the same package that satisfy the interface specified by the +declaration. + +The `go-check-sumtype` command will prove its worth when you need to add a variant +to an existing sum type. Running `go-check-sumtype` will tell you immediately which +case analyses need to be updated to account for the new variant. diff --git a/vendor/github.com/alecthomas/go-check-sumtype/UNLICENSE b/vendor/github.com/alecthomas/go-check-sumtype/UNLICENSE new file mode 100644 index 000000000..68a49daad --- /dev/null +++ b/vendor/github.com/alecthomas/go-check-sumtype/UNLICENSE @@ -0,0 +1,24 @@ +This is free and unencumbered software released into the public domain. + +Anyone is free to copy, modify, publish, use, compile, sell, or +distribute this software, either in source code form or as a compiled +binary, for any purpose, commercial or non-commercial, and by any +means. + +In jurisdictions that recognize copyright laws, the author or authors +of this software dedicate any and all copyright interest in the +software to the public domain. We make this dedication for the benefit +of the public at large and to the detriment of our heirs and +successors. We intend this dedication to be an overt act of +relinquishment in perpetuity of all present and future rights to this +software under copyright law. + +THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF +MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. +IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR +OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, +ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR +OTHER DEALINGS IN THE SOFTWARE. + +For more information, please refer to <http://unlicense.org/> diff --git a/vendor/github.com/alecthomas/go-check-sumtype/check.go b/vendor/github.com/alecthomas/go-check-sumtype/check.go new file mode 100644 index 000000000..21d751af4 --- /dev/null +++ b/vendor/github.com/alecthomas/go-check-sumtype/check.go @@ -0,0 +1,184 @@ +package gochecksumtype + +import ( + "fmt" + "go/ast" + "go/token" + "go/types" + "sort" + "strings" + + "golang.org/x/tools/go/packages" +) + +// inexhaustiveError is returned from check for each occurrence of inexhaustive +// case analysis in a Go type switch statement. +type inexhaustiveError struct { + Position token.Position + Def sumTypeDef + Missing []types.Object +} + +func (e inexhaustiveError) Pos() token.Position { return e.Position } +func (e inexhaustiveError) Error() string { + return fmt.Sprintf( + "%s: exhaustiveness check failed for sum type %q (from %s): missing cases for %s", + e.Pos(), e.Def.Decl.TypeName, e.Def.Decl.Pos, strings.Join(e.Names(), ", ")) +} + +// Names returns a sorted list of names corresponding to the missing variant +// cases. +func (e inexhaustiveError) Names() []string { + var list []string + for _, o := range e.Missing { + list = append(list, o.Name()) + } + sort.Strings(list) + return list +} + +// check does exhaustiveness checking for the given sum type definitions in the +// given package. Every instance of inexhaustive case analysis is returned. +func check(pkg *packages.Package, defs []sumTypeDef) []error { + var errs []error + for _, astfile := range pkg.Syntax { + ast.Inspect(astfile, func(n ast.Node) bool { + swtch, ok := n.(*ast.TypeSwitchStmt) + if !ok { + return true + } + if err := checkSwitch(pkg, defs, swtch); err != nil { + errs = append(errs, err) + } + return true + }) + } + return errs +} + +// checkSwitch performs an exhaustiveness check on the given type switch +// statement. If the type switch is used on a sum type and does not cover +// all variants of that sum type, then an error is returned indicating which +// variants were missed. +// +// Note that if the type switch contains a non-panicing default case, then +// exhaustiveness checks are disabled. +func checkSwitch( + pkg *packages.Package, + defs []sumTypeDef, + swtch *ast.TypeSwitchStmt, +) error { + def, missing := missingVariantsInSwitch(pkg, defs, swtch) + if len(missing) > 0 { + return inexhaustiveError{ + Position: pkg.Fset.Position(swtch.Pos()), + Def: *def, + Missing: missing, + } + } + return nil +} + +// missingVariantsInSwitch returns a list of missing variants corresponding to +// the given switch statement. The corresponding sum type definition is also +// returned. (If no sum type definition could be found, then no exhaustiveness +// checks are performed, and therefore, no missing variants are returned.) +func missingVariantsInSwitch( + pkg *packages.Package, + defs []sumTypeDef, + swtch *ast.TypeSwitchStmt, +) (*sumTypeDef, []types.Object) { + asserted := findTypeAssertExpr(swtch) + ty := pkg.TypesInfo.TypeOf(asserted) + def := findDef(defs, ty) + if def == nil { + // We couldn't find a corresponding sum type, so there's + // nothing we can do to check it. + return nil, nil + } + variantExprs, hasDefault := switchVariants(swtch) + if hasDefault && !defaultClauseAlwaysPanics(swtch) { + // A catch-all case defeats all exhaustiveness checks. + return def, nil + } + var variantTypes []types.Type + for _, expr := range variantExprs { + variantTypes = append(variantTypes, pkg.TypesInfo.TypeOf(expr)) + } + return def, def.missing(variantTypes) +} + +// switchVariants returns all case expressions found in a type switch. This +// includes expressions from cases that have a list of expressions. +func switchVariants(swtch *ast.TypeSwitchStmt) (exprs []ast.Expr, hasDefault bool) { + for _, stmt := range swtch.Body.List { + clause := stmt.(*ast.CaseClause) + if clause.List == nil { + hasDefault = true + } else { + exprs = append(exprs, clause.List...) + } + } + return +} + +// defaultClauseAlwaysPanics returns true if the given switch statement has a +// default clause that always panics. Note that this is done on a best-effort +// basis. While there will never be any false positives, there may be false +// negatives. +// +// If the given switch statement has no default clause, then this function +// panics. +func defaultClauseAlwaysPanics(swtch *ast.TypeSwitchStmt) bool { + var clause *ast.CaseClause + for _, stmt := range swtch.Body.List { + c := stmt.(*ast.CaseClause) + if c.List == nil { + clause = c + break + } + } + if clause == nil { + panic("switch statement has no default clause") + } + if len(clause.Body) != 1 { + return false + } + exprStmt, ok := clause.Body[0].(*ast.ExprStmt) + if !ok { + return false + } + callExpr, ok := exprStmt.X.(*ast.CallExpr) + if !ok { + return false + } + fun, ok := callExpr.Fun.(*ast.Ident) + if !ok { + return false + } + return fun.Name == "panic" +} + +// findTypeAssertExpr extracts the expression that is being type asserted from a +// type swtich statement. +func findTypeAssertExpr(swtch *ast.TypeSwitchStmt) ast.Expr { + var expr ast.Expr + if assign, ok := swtch.Assign.(*ast.AssignStmt); ok { + expr = assign.Rhs[0] + } else { + expr = swtch.Assign.(*ast.ExprStmt).X + } + return expr.(*ast.TypeAssertExpr).X +} + +// findDef returns the sum type definition corresponding to the given type. If +// no such sum type definition exists, then nil is returned. +func findDef(defs []sumTypeDef, needle types.Type) *sumTypeDef { + for i := range defs { + def := &defs[i] + if types.Identical(needle.Underlying(), def.Ty) { + return def + } + } + return nil +} diff --git a/vendor/github.com/alecthomas/go-check-sumtype/decl.go b/vendor/github.com/alecthomas/go-check-sumtype/decl.go new file mode 100644 index 000000000..ea2cd06df --- /dev/null +++ b/vendor/github.com/alecthomas/go-check-sumtype/decl.go @@ -0,0 +1,68 @@ +package gochecksumtype + +import ( + "go/ast" + "go/token" + "strings" + + "golang.org/x/tools/go/packages" +) + +// sumTypeDecl is a declaration of a sum type in a Go source file. +type sumTypeDecl struct { + // The package path that contains this decl. + Package *packages.Package + // The type named by this decl. + TypeName string + // Position where the declaration was found. + Pos token.Position +} + +// Location returns a short string describing where this declaration was found. +func (d sumTypeDecl) Location() string { + return d.Pos.String() +} + +// findSumTypeDecls searches every package given for sum type declarations of +// the form `sumtype:decl`. +func findSumTypeDecls(pkgs []*packages.Package) ([]sumTypeDecl, error) { + var decls []sumTypeDecl + var retErr error + for _, pkg := range pkgs { + for _, file := range pkg.Syntax { + ast.Inspect(file, func(node ast.Node) bool { + if node == nil { + return true + } + decl, ok := node.(*ast.GenDecl) + if !ok || decl.Doc == nil { + return true + } + var tspec *ast.TypeSpec + for _, spec := range decl.Specs { + ts, ok := spec.(*ast.TypeSpec) + if !ok { + continue + } + tspec = ts + } + for _, line := range decl.Doc.List { + if !strings.HasPrefix(line.Text, "//sumtype:decl") { + continue + } + pos := pkg.Fset.Position(decl.Pos()) + if tspec == nil { + retErr = notFoundError{Decl: sumTypeDecl{Package: pkg, Pos: pos}} + return false + } + pos = pkg.Fset.Position(tspec.Pos()) + decl := sumTypeDecl{Package: pkg, TypeName: tspec.Name.Name, Pos: pos} + decls = append(decls, decl) + break + } + return true + }) + } + } + return decls, retErr +} diff --git a/vendor/github.com/alecthomas/go-check-sumtype/def.go b/vendor/github.com/alecthomas/go-check-sumtype/def.go new file mode 100644 index 000000000..811b98f98 --- /dev/null +++ b/vendor/github.com/alecthomas/go-check-sumtype/def.go @@ -0,0 +1,157 @@ +package gochecksumtype + +import ( + "fmt" + "go/token" + "go/types" +) + +// Error as returned by Run() +type Error interface { + error + Pos() token.Position +} + +// unsealedError corresponds to a declared sum type whose interface is not +// sealed. A sealed interface requires at least one unexported method. +type unsealedError struct { + Decl sumTypeDecl +} + +func (e unsealedError) Pos() token.Position { return e.Decl.Pos } +func (e unsealedError) Error() string { + return fmt.Sprintf( + "%s: interface '%s' is not sealed "+ + "(sealing requires at least one unexported method)", + e.Decl.Location(), e.Decl.TypeName) +} + +// notFoundError corresponds to a declared sum type whose type definition +// could not be found in the same Go package. +type notFoundError struct { + Decl sumTypeDecl +} + +func (e notFoundError) Pos() token.Position { return e.Decl.Pos } +func (e notFoundError) Error() string { + return fmt.Sprintf("%s: type '%s' is not defined", e.Decl.Location(), e.Decl.TypeName) +} + +// notInterfaceError corresponds to a declared sum type that does not +// correspond to an interface. +type notInterfaceError struct { + Decl sumTypeDecl +} + +func (e notInterfaceError) Pos() token.Position { return e.Decl.Pos } +func (e notInterfaceError) Error() string { + return fmt.Sprintf("%s: type '%s' is not an interface", e.Decl.Location(), e.Decl.TypeName) +} + +// sumTypeDef corresponds to the definition of a Go interface that is +// interpreted as a sum type. Its variants are determined by finding all types +// that implement said interface in the same package. +type sumTypeDef struct { + Decl sumTypeDecl + Ty *types.Interface + Variants []types.Object +} + +// findSumTypeDefs attempts to find a Go type definition for each of the given +// sum type declarations. If no such sum type definition could be found for +// any of the given declarations, then an error is returned. +func findSumTypeDefs(decls []sumTypeDecl) ([]sumTypeDef, []error) { + var defs []sumTypeDef + var errs []error + for _, decl := range decls { + def, err := newSumTypeDef(decl.Package.Types, decl) + if err != nil { + errs = append(errs, err) + continue + } + if def == nil { + errs = append(errs, notFoundError{decl}) + continue + } + defs = append(defs, *def) + } + return defs, errs +} + +// newSumTypeDef attempts to extract a sum type definition from a single +// package. If no such type corresponds to the given decl, then this function +// returns a nil def and a nil error. +// +// If the decl corresponds to a type that isn't an interface containing at +// least one unexported method, then this returns an error. +func newSumTypeDef(pkg *types.Package, decl sumTypeDecl) (*sumTypeDef, error) { + obj := pkg.Scope().Lookup(decl.TypeName) + if obj == nil { + return nil, nil + } + iface, ok := obj.Type().Underlying().(*types.Interface) + if !ok { + return nil, notInterfaceError{decl} + } + hasUnexported := false + for i := 0; i < iface.NumMethods(); i++ { + if !iface.Method(i).Exported() { + hasUnexported = true + break + } + } + if !hasUnexported { + return nil, unsealedError{decl} + } + def := &sumTypeDef{ + Decl: decl, + Ty: iface, + } + for _, name := range pkg.Scope().Names() { + obj, ok := pkg.Scope().Lookup(name).(*types.TypeName) + if !ok { + continue + } + ty := obj.Type() + if types.Identical(ty.Underlying(), iface) { + continue + } + if types.Implements(ty, iface) || types.Implements(types.NewPointer(ty), iface) { + def.Variants = append(def.Variants, obj) + } + } + return def, nil +} + +func (def *sumTypeDef) String() string { + return def.Decl.TypeName +} + +// missing returns a list of variants in this sum type that are not in the +// given list of types. +func (def *sumTypeDef) missing(tys []types.Type) []types.Object { + // TODO(ag): This is O(n^2). Fix that. /shrug + var missing []types.Object + for _, v := range def.Variants { + found := false + varty := indirect(v.Type()) + for _, ty := range tys { + ty = indirect(ty) + if types.Identical(varty, ty) { + found = true + } + } + if !found { + missing = append(missing, v) + } + } + return missing +} + +// indirect dereferences through an arbitrary number of pointer types. +func indirect(ty types.Type) types.Type { + if ty, ok := ty.(*types.Pointer); ok { + return indirect(ty.Elem()) + } + return ty +} diff --git a/vendor/github.com/alecthomas/go-check-sumtype/doc.go b/vendor/github.com/alecthomas/go-check-sumtype/doc.go new file mode 100644 index 000000000..2b6e86764 --- /dev/null +++ b/vendor/github.com/alecthomas/go-check-sumtype/doc.go @@ -0,0 +1,53 @@ +/* +sumtype takes a list of Go package paths or files and looks for sum type +declarations in each package/file provided. Exhaustiveness checks are then +performed for each use of a declared sum type in a type switch statement. +Namely, sumtype will report an error for any type switch statement that +either lacks a default clause or does not account for all possible variants. + +Declarations are provided in comments like so: + + //sumtype:decl + type MySumType interface { ... } + +MySumType must be *sealed*. That is, part of its interface definition contains +an unexported method. + +sumtype will produce an error if any of the above is not true. + +For valid declarations, sumtype will look for all occurrences in which a +value of type MySumType participates in a type switch statement. In those +occurrences, it will attempt to detect whether the type switch is exhaustive +or not. If it's not, sumtype will report an error. For example: + + $ cat mysumtype.go + package gochecksumtype + + //sumtype:decl + type MySumType interface { + sealed() + } + + type VariantA struct{} + + func (a *VariantA) sealed() {} + + type VariantB struct{} + + func (b *VariantB) sealed() {} + + func main() { + switch MySumType(nil).(type) { + case *VariantA: + } + } + $ sumtype mysumtype.go + mysumtype.go:18:2: exhaustiveness check failed for sum type 'MySumType': missing cases for VariantB + +Adding either a default clause or a clause to handle *VariantB will cause +exhaustive checks to pass. + +As a special case, if the type switch statement contains a default clause +that always panics, then exhaustiveness checks are still performed. +*/ +package gochecksumtype diff --git a/vendor/github.com/alecthomas/go-check-sumtype/run.go b/vendor/github.com/alecthomas/go-check-sumtype/run.go new file mode 100644 index 000000000..fdcb643c5 --- /dev/null +++ b/vendor/github.com/alecthomas/go-check-sumtype/run.go @@ -0,0 +1,26 @@ +package gochecksumtype + +import "golang.org/x/tools/go/packages" + +// Run sumtype checking on the given packages. +func Run(pkgs []*packages.Package) []error { + var errs []error + + decls, err := findSumTypeDecls(pkgs) + if err != nil { + return []error{err} + } + + defs, defErrs := findSumTypeDefs(decls) + errs = append(errs, defErrs...) + if len(defs) == 0 { + return errs + } + + for _, pkg := range pkgs { + if pkgErrs := check(pkg, defs); pkgErrs != nil { + errs = append(errs, pkgErrs...) + } + } + return errs +} |