feat: detect in nested blocks

This commit is contained in:
Gabriel Augendre 2024-07-12 12:04:01 +02:00 committed by Gabriel Augendre
parent f35e8a2263
commit 091030580e
2 changed files with 220 additions and 57 deletions

View file

@ -36,64 +36,39 @@ func run(pass *analysis.Pass) (interface{}, error) {
return return
} }
for _, stmt := range body.List { assignStmt := findNestedContext(pass, body, body.List)
assignStmt, ok := stmt.(*ast.AssignStmt) if assignStmt == nil {
if !ok { return
continue
}
t := pass.TypesInfo.TypeOf(assignStmt.Lhs[0])
if t == nil {
continue
}
if t.String() != "context.Context" {
continue
}
if assignStmt.Tok == token.DEFINE {
break
}
// allow assignment to non-pointer children of values defined within the loop
if lhs := getRootIdent(pass, assignStmt.Lhs[0]); lhs != nil {
if obj := pass.TypesInfo.ObjectOf(lhs); obj != nil {
if obj.Pos() >= body.Pos() && obj.Pos() < body.End() {
continue // definition is within the loop
}
}
}
suggestedStmt := ast.AssignStmt{
Lhs: assignStmt.Lhs,
TokPos: assignStmt.TokPos,
Tok: token.DEFINE,
Rhs: assignStmt.Rhs,
}
suggested, err := render(pass.Fset, &suggestedStmt)
var fixes []analysis.SuggestedFix
if err == nil {
fixes = append(fixes, analysis.SuggestedFix{
Message: "replace `=` with `:=`",
TextEdits: []analysis.TextEdit{
{
Pos: assignStmt.Pos(),
End: assignStmt.End(),
NewText: []byte(suggested),
},
},
})
}
pass.Report(analysis.Diagnostic{
Pos: assignStmt.Pos(),
Message: "nested context in loop",
SuggestedFixes: fixes,
})
break
} }
suggestedStmt := ast.AssignStmt{
Lhs: assignStmt.Lhs,
TokPos: assignStmt.TokPos,
Tok: token.DEFINE,
Rhs: assignStmt.Rhs,
}
suggested, err := render(pass.Fset, &suggestedStmt)
var fixes []analysis.SuggestedFix
if err == nil {
fixes = append(fixes, analysis.SuggestedFix{
Message: "replace `=` with `:=`",
TextEdits: []analysis.TextEdit{
{
Pos: assignStmt.Pos(),
End: assignStmt.End(),
NewText: []byte(suggested),
},
},
})
}
pass.Report(analysis.Diagnostic{
Pos: assignStmt.Pos(),
Message: "nested context in loop",
SuggestedFixes: fixes,
})
}) })
return nil, nil return nil, nil
@ -113,6 +88,85 @@ func getBody(node ast.Node) (*ast.BlockStmt, error) {
return nil, errUnknown return nil, errUnknown
} }
func findNestedContext(pass *analysis.Pass, block *ast.BlockStmt, stmts []ast.Stmt) *ast.AssignStmt {
for _, stmt := range stmts {
// Recurse if necessary
if inner, ok := stmt.(*ast.BlockStmt); ok {
found := findNestedContext(pass, inner, inner.List)
if found != nil {
return found
}
}
if inner, ok := stmt.(*ast.IfStmt); ok {
found := findNestedContext(pass, inner.Body, inner.Body.List)
if found != nil {
return found
}
}
if inner, ok := stmt.(*ast.SwitchStmt); ok {
found := findNestedContext(pass, inner.Body, inner.Body.List)
if found != nil {
return found
}
}
if inner, ok := stmt.(*ast.CaseClause); ok {
found := findNestedContext(pass, block, inner.Body)
if found != nil {
return found
}
}
if inner, ok := stmt.(*ast.SelectStmt); ok {
found := findNestedContext(pass, inner.Body, inner.Body.List)
if found != nil {
return found
}
}
if inner, ok := stmt.(*ast.CommClause); ok {
found := findNestedContext(pass, block, inner.Body)
if found != nil {
return found
}
}
// Actually check for nested context
assignStmt, ok := stmt.(*ast.AssignStmt)
if !ok {
continue
}
t := pass.TypesInfo.TypeOf(assignStmt.Lhs[0])
if t == nil {
continue
}
if t.String() != "context.Context" {
continue
}
if assignStmt.Tok == token.DEFINE {
break
}
// allow assignment to non-pointer children of values defined within the loop
if lhs := getRootIdent(pass, assignStmt.Lhs[0]); lhs != nil {
if obj := pass.TypesInfo.ObjectOf(lhs); obj != nil {
if obj.Pos() >= block.Pos() && obj.Pos() < block.End() {
continue // definition is within the loop
}
}
}
return assignStmt
}
return nil
}
func getRootIdent(pass *analysis.Pass, node ast.Node) *ast.Ident { func getRootIdent(pass *analysis.Pass, node ast.Node) *ast.Ident {
for { for {
switch n := node.(type) { switch n := node.(type) {

View file

@ -25,12 +25,50 @@ func example() {
ctx = wrapContext(ctx) // want "nested context in loop" ctx = wrapContext(ctx) // want "nested context in loop"
break break
} }
// not fooled by shadowing in nested blocks
for {
err := doSomething()
if err != nil {
ctx := wrapContext(ctx)
ctx = wrapContext(ctx)
}
switch err {
case nil:
ctx := wrapContext(ctx)
ctx = wrapContext(ctx)
default:
ctx := wrapContext(ctx)
ctx = wrapContext(ctx)
}
{
ctx := wrapContext(ctx)
ctx = wrapContext(ctx)
}
select {
case <-ctx.Done():
ctx := wrapContext(ctx)
ctx = wrapContext(ctx)
default:
}
ctx = wrapContext(ctx) // want "nested context in loop"
break
}
} }
func wrapContext(ctx context.Context) context.Context { func wrapContext(ctx context.Context) context.Context {
return context.WithoutCancel(ctx) return context.WithoutCancel(ctx)
} }
func doSomething() error {
return nil
}
// storing contexts in a struct isn't recommended, but local copies of a non-pointer struct should act like local copies of a context. // storing contexts in a struct isn't recommended, but local copies of a non-pointer struct should act like local copies of a context.
func inStructs(ctx context.Context) { func inStructs(ctx context.Context) {
for i := 0; i < 10; i++ { for i := 0; i < 10; i++ {
@ -71,3 +109,74 @@ func inStructs(ctx context.Context) {
rp[0].Ctx = context.WithValue(rp[0].Ctx, "other", "val") rp[0].Ctx = context.WithValue(rp[0].Ctx, "other", "val")
} }
} }
func inVariousNestedBlocks(ctx context.Context) {
for {
err := doSomething()
if err != nil {
ctx = wrapContext(ctx) // want "nested context in loop"
}
break
}
for {
err := doSomething()
if err != nil {
if true {
ctx = wrapContext(ctx) // want "nested context in loop"
}
}
break
}
for {
err := doSomething()
switch err {
case nil:
ctx = wrapContext(ctx) // want "nested context in loop"
}
break
}
for {
err := doSomething()
switch err {
default:
ctx = wrapContext(ctx) // want "nested context in loop"
}
break
}
for {
ctx := wrapContext(ctx)
err := doSomething()
if err != nil {
ctx = wrapContext(ctx)
}
break
}
for {
{
ctx = wrapContext(ctx) // want "nested context in loop"
}
break
}
for {
select {
case <-ctx.Done():
ctx = wrapContext(ctx) // want "nested context in loop"
default:
}
break
}
}