cmd/vet: add defers analysis pass

Fixes #60048

Change-Id: I1553de35d5ebd9c7df9727242e888de91caca4ea
Reviewed-on: https://go-review.googlesource.com/c/go/+/527095
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Tim King <taking@google.com>
Reviewed-by: Tim King <taking@google.com>

diff --git a/src/cmd/go/internal/test/flagdefs.go b/src/cmd/go/internal/test/flagdefs.go
index 947c27ef05e57edd190ed4e91fbf2aeef0aa7468..12d506862dde91a0e8434e23abf3f0f2e962092e 100644 (file)
--- a/src/cmd/go/internal/test/flagdefs.go
+++ b/src/cmd/go/internal/test/flagdefs.go
@@ -50,6 +50,7 @@ var passAnalyzersToVet = map[string]bool{
        "cgocall":          true,
        "composites":       true,
        "copylocks":        true,
+       "defers":           true,
        "directive":        true,
        "errorsas":         true,
        "framepointer":     true,

diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/defers/defers.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/defers/defers.go
new file mode 100644 (file)
index 0000000..ed2a122
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/defers/defers.go
@@ -0,0 +1,61 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package defers
+
+import (
+       _ "embed"
+       "go/ast"
+       "go/types"
+
+       "golang.org/x/tools/go/analysis"
+       "golang.org/x/tools/go/analysis/passes/inspect"
+       "golang.org/x/tools/go/analysis/passes/internal/analysisutil"
+       "golang.org/x/tools/go/ast/inspector"
+       "golang.org/x/tools/go/types/typeutil"
+)
+
+//go:embed doc.go
+var doc string
+
+// Analyzer is the defers analyzer.
+var Analyzer = &analysis.Analyzer{
+       Name:     "defers",
+       Requires: []*analysis.Analyzer{inspect.Analyzer},
+       URL:      "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/defers",
+       Doc:      analysisutil.MustExtractDoc(doc, "defers"),
+       Run:      run,
+}
+
+func run(pass *analysis.Pass) (interface{}, error) {
+       if !analysisutil.Imports(pass.Pkg, "time") {
+               return nil, nil
+       }
+
+       checkDeferCall := func(node ast.Node) bool {
+               switch v := node.(type) {
+               case *ast.CallExpr:
+                       fn, ok := typeutil.Callee(pass.TypesInfo, v).(*types.Func)
+                       if ok && fn.Name() == "Since" && fn.Pkg().Path() == "time" {
+                               pass.Reportf(v.Pos(), "call to time.Since is not deferred")
+                       }
+               case *ast.FuncLit:
+                       return false // prune
+               }
+               return true
+       }
+
+       inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
+
+       nodeFilter := []ast.Node{
+               (*ast.DeferStmt)(nil),
+       }
+
+       inspect.Preorder(nodeFilter, func(n ast.Node) {
+               d := n.(*ast.DeferStmt)
+               ast.Inspect(d.Call, checkDeferCall)
+       })
+
+       return nil, nil
+}

diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/defers/doc.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/defers/doc.go
new file mode 100644 (file)
index 0000000..bdb1351
--- /dev/null
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/defers/doc.go
@@ -0,0 +1,25 @@
+// Copyright 2023 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Package defers defines an Analyzer that checks for common mistakes in defer
+// statements.
+//
+// # Analyzer defers
+//
+// defers: report common mistakes in defer statements
+//
+// The defers analyzer reports a diagnostic when a defer statement would
+// result in a non-deferred call to time.Since, as experience has shown
+// that this is nearly always a mistake.
+//
+// For example:
+//
+//     start := time.Now()
+//     ...
+//     defer recordLatency(time.Since(start)) // error: call to time.Since is not deferred
+//
+// The correct code is:
+//
+//     defer func() { recordLatency(time.Since(start)) }()
+package defers

diff --git a/src/cmd/vendor/modules.txt b/src/cmd/vendor/modules.txt
index 380a05bf6340aa69ce86474edee72854cf86e93c..a2b1e248be8f552d5620cf1c6f5d8f8156ce116a 100644 (file)
--- a/src/cmd/vendor/modules.txt
+++ b/src/cmd/vendor/modules.txt
@@ -61,6 +61,7 @@ golang.org/x/tools/go/analysis/passes/cgocall
 golang.org/x/tools/go/analysis/passes/composite
 golang.org/x/tools/go/analysis/passes/copylock
 golang.org/x/tools/go/analysis/passes/ctrlflow
+golang.org/x/tools/go/analysis/passes/defers
 golang.org/x/tools/go/analysis/passes/directive
 golang.org/x/tools/go/analysis/passes/errorsas
 golang.org/x/tools/go/analysis/passes/framepointer

diff --git a/src/cmd/vet/main.go b/src/cmd/vet/main.go
index a90758f8236f1b90eaa3281f8890da5341e2e9ef..2290b95033c2a428113cd228204daf9b2641316b 100644 (file)
--- a/src/cmd/vet/main.go
+++ b/src/cmd/vet/main.go
@@ -17,6 +17,7 @@ import (
        "golang.org/x/tools/go/analysis/passes/cgocall"
        "golang.org/x/tools/go/analysis/passes/composite"
        "golang.org/x/tools/go/analysis/passes/copylock"
+       "golang.org/x/tools/go/analysis/passes/defers"
        "golang.org/x/tools/go/analysis/passes/directive"
        "golang.org/x/tools/go/analysis/passes/errorsas"
        "golang.org/x/tools/go/analysis/passes/framepointer"
@@ -53,6 +54,7 @@ func main() {
                cgocall.Analyzer,
                composite.Analyzer,
                copylock.Analyzer,
+               defers.Analyzer,
                directive.Analyzer,
                errorsas.Analyzer,
                framepointer.Analyzer,