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fix(reliability): make goroutine-in-loop detection linear to avoid quadratic AST walks #130

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Merged
alxxjohn merged 1 commit into from
Aug 18, 2026
Merged

fix(reliability): make goroutine-in-loop detection linear to avoid quadratic AST walks #130

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18 changes: 17 additions & 1 deletion internal/codeguard/checks/reliability/reliability_go.go
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Original file line number Diff line number Diff line change
Expand Up @@ -42,12 +42,21 @@ func functionReliabilityFindings(env support.Context, file string, fset *token.F
deferCloseVars := deferredCloseVars(fn.Body)
boundedClients, boundedRequests := boundedHTTPValues(fn.Body, httpAliases)
goroutines := 0
loopDepth := 0
var loopStack []bool

ast.Inspect(fn.Body, func(node ast.Node) bool {
if node == nil {
if loopStack[len(loopStack)-1] {
loopDepth--
}
loopStack = loopStack[:len(loopStack)-1]
return true
}
switch n := node.(type) {
case *ast.GoStmt:
goroutines++
if enabled(rules.DetectUnboundedWork) && isInsideLoop(fn.Body, n) {
if enabled(rules.DetectUnboundedWork) && loopDepth > 0 {
pos := fset.Position(n.Go)
findings = append(findings, newFinding(env, "reliability.unbounded-work", "warn", file, pos.Line, pos.Column, "goroutine launched inside a loop without an obvious work bound", "high", "work", "goroutine-in-loop"))
}
Expand All @@ -67,6 +76,13 @@ func functionReliabilityFindings(env support.Context, file string, fset *token.F
findings = append(findings, lostErrorContextFindings(env, file, fset, n)...)
}
}
_, isFor := node.(*ast.ForStmt)
_, isRange := node.(*ast.RangeStmt)
isLoop := isFor || isRange
loopStack = append(loopStack, isLoop)
if isLoop {
loopDepth++
}
return true
})

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25 changes: 0 additions & 25 deletions internal/codeguard/checks/reliability/reliability_go_helpers.go
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Original file line number Diff line number Diff line change
Expand Up @@ -334,31 +334,6 @@ func fileHasSelector(parsed *ast.File, selector string) bool {
return found
}

func isInsideLoop(root ast.Node, target ast.Node) bool {
inside := false
var stack []ast.Node
ast.Inspect(root, func(node ast.Node) bool {
if node == nil {
if len(stack) > 0 {
stack = stack[:len(stack)-1]
}
return true
}
if node == target {
for _, item := range stack {
switch item.(type) {
case *ast.ForStmt, *ast.RangeStmt:
inside = true
return false
}
}
}
stack = append(stack, node)
return true
})
return inside
}

func isErrorsNewCall(call *ast.CallExpr) bool {
selector, ok := call.Fun.(*ast.SelectorExpr)
if !ok || selector.Sel.Name != "New" {
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