87aae77943
Fix #324, relates #314 1. Update gocritic to the latest version 2. Use proper gocritic checkers repo, old repo was archived 3. Get enabled by default gocritic checks in sync with go-critic: don't enable performance, experimental and opinionated checks by default 4. Support of `enabled-tags` options for gocritic 5. Enable almost all gocritic checks for the project 6. Make rich debugging for gocritic 7. Meticulously validate gocritic checks config
103 lines
2.5 KiB
Go
103 lines
2.5 KiB
Go
package checkers
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import (
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"go/ast"
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"go/token"
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"go/types"
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"github.com/go-lintpack/lintpack"
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"github.com/go-lintpack/lintpack/astwalk"
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"github.com/go-toolsmith/astequal"
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"github.com/go-toolsmith/astp"
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"golang.org/x/tools/go/ast/astutil"
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)
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func init() {
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var info lintpack.CheckerInfo
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info.Name = "appendAssign"
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info.Tags = []string{"diagnostic"}
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info.Summary = "Detects suspicious append result assignments"
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info.Before = `
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p.positives = append(p.negatives, x)
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p.negatives = append(p.negatives, y)`
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info.After = `
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p.positives = append(p.positives, x)
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p.negatives = append(p.negatives, y)`
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collection.AddChecker(&info, func(ctx *lintpack.CheckerContext) lintpack.FileWalker {
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return astwalk.WalkerForStmt(&appendAssignChecker{ctx: ctx})
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})
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}
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type appendAssignChecker struct {
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astwalk.WalkHandler
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ctx *lintpack.CheckerContext
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}
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func (c *appendAssignChecker) VisitStmt(stmt ast.Stmt) {
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assign, ok := stmt.(*ast.AssignStmt)
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if !ok || assign.Tok != token.ASSIGN || len(assign.Lhs) != len(assign.Rhs) {
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return
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}
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for i, rhs := range assign.Rhs {
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call, ok := rhs.(*ast.CallExpr)
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if !ok || qualifiedName(call.Fun) != "append" {
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continue
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}
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c.checkAppend(assign.Lhs[i], call)
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}
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}
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func (c *appendAssignChecker) checkAppend(x ast.Expr, call *ast.CallExpr) {
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if call.Ellipsis != token.NoPos {
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// Try to detect `xs = append(ys, xs...)` idiom.
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for _, arg := range call.Args[1:] {
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y := arg
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if arg, ok := arg.(*ast.SliceExpr); ok {
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y = arg.X
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}
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if astequal.Expr(x, y) {
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return
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}
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}
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}
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switch x := x.(type) {
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case *ast.Ident:
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if x.Name == "_" {
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return // Don't check assignments to blank ident
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}
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case *ast.IndexExpr:
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if !astp.IsIndexExpr(call.Args[0]) {
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// Most likely `m[k] = append(x, ...)`
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// pattern, where x was retrieved by m[k] before.
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//
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// TODO: it's possible to record such map/slice reads
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// and check whether it was done before this call.
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// But for now, treat it like x belongs to m[k].
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return
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}
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}
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switch y := call.Args[0].(type) {
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case *ast.SliceExpr:
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if _, ok := c.ctx.TypesInfo.TypeOf(y.X).(*types.Array); ok {
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// Arrays are frequently used as scratch storages.
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return
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}
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c.matchSlices(call, x, y.X)
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case *ast.IndexExpr, *ast.Ident, *ast.SelectorExpr:
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c.matchSlices(call, x, y)
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}
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}
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func (c *appendAssignChecker) matchSlices(cause ast.Node, x, y ast.Expr) {
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if !astequal.Expr(x, astutil.Unparen(y)) {
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c.warn(cause)
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}
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}
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func (c *appendAssignChecker) warn(cause ast.Node) {
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c.ctx.Warn(cause, "append result not assigned to the same slice")
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}
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