modify prompt

README.md

@@ -3,16 +3,20 @@
 
 # contextcheck
 
-`contextcheck` is a static analysis tool, it is used to check a function whether use context.Background() or context.TODO() directly instead of the input ctx when calling the sub-function, or even don't pass the ctx, which will result in a broken call link.
+`contextcheck` is a static analysis tool, it is used to check the function whether use a non-inherited context, which will result in a broken call link.
 
 For example:
 
 ```go
 func call1(ctx context.Context) {
  ...
- call2(context.Background()) // should use ctx
 
- call3() // should pass the ctx
+ ctx = getNewCtx(ctx)
+ call2(ctx) // OK
+
+ call2(context.Background()) // Non-inherited new context, use function like `context.WithXXX` instead
+
+ call3() // Function `call3` should pass the context parameter
  ...
 }
 
@@ -24,6 +28,11 @@ func call3() {
  ctx := context.TODO()
  call2(ctx)
 }
+
+func getNewCtx(ctx context.Context) (newCtx context.Context) {
+ ...
+ return
+}
 ```
 
 ## Installation
@@ -48,5 +57,5 @@ Invoke `contextcheck` with your package name
 ```bash
 $ contextcheck ./...
 $ # or
-$ contextcheck github.com/you/yourproject/...
+$ go vet -vettool=`which contextcheck` ./...
 ```

contextcheck.go

@@ -17,7 +17,7 @@ import (
 func NewAnalyzer() *analysis.Analyzer {
  return &analysis.Analyzer{
  Name: "contextcheck",
- Doc: "checkInstr for using context.Background() and context.TODO() directly",
+ Doc: "check the function whether use a non-inherited context",
  Run: NewRun(),
  Requires: []*analysis.Analyzer{
  buildssa.Analyzer,
@@ -247,15 +247,15 @@ func (r *runner) collectCtxRef(f *ssa.Function) (refMap map[ssa.Instruction]bool
 
  for instr := range storeInstrs {
  if !checkedRefMap[instr.Val] {
- r.pass.Reportf(instr.Pos(), "Invalid call to get new context, please replace it with another way, such as context.WithValue(ctx, key, val)")
+ r.pass.Reportf(instr.Pos(), "Non-inherited new context, use function like `context.WithXXX` instead")
  ok = false
  }
  }
 
  for instr := range phiInstrs {
  for _, v := range instr.Edges {
  if !checkedRefMap[v] {
- r.pass.Reportf(instr.Pos(), "Invalid call to get new context, please replace it with another way, such as context.WithValue(ctx, key, val)")
+ r.pass.Reportf(instr.Pos(), "Non-inherited new context, use function like `context.WithXXX` instead")
  ok = false
  }
  }
@@ -299,7 +299,7 @@ func (r *runner) checkFuncWithCtx(f *ssa.Function) {
 
  if tp&CtxIn != 0 {
  if !refMap[instr] {
- r.pass.Reportf(instr.Pos(), "The context param may be context.TODO() or context.Background(), please replace it with another way, such as context.WithValue(ctx, key, val)")
+ r.pass.Reportf(instr.Pos(), "Non-inherited new context, use function like `context.WithXXX` instead")
  }
  }
 

testdata/src/a/a.go

@@ -45,7 +45,7 @@ func f1(ctx context.Context) {
  f2(ctx)
  }(ctx)
 
- f2(context.Background()) // want `The context param may be context\.TODO\(\) or context\.Background\(\), please replace it with another way, such as context\.WithValue\(ctx, key, val\)`
+ f2(context.Background()) // want "Non-inherited new context, use function like `context.WithXXX` instead"
 
  thunk := MyInt.F
  thunk(0)
@@ -63,18 +63,29 @@ func f3() {
 func f4(ctx context.Context) {
  f2(ctx)
  ctx = context.Background()
- f2(ctx) // want `The context param may be context\.TODO\(\) or context\.Background\(\), please replace it with another way, such as context\.WithValue\(ctx, key, val\)`
+ f2(ctx) // want "Non-inherited new context, use function like `context.WithXXX` instead"
 }
 
 func f5(ctx context.Context) {
  func() {
  f2(ctx)
  }()
 
- ctx = context.Background() // want `Invalid call to get new context, please replace it with another way, such as context\.WithValue\(ctx, key, val\)`
+ ctx = context.Background() // want "Non-inherited new context, use function like `context.WithXXX` instead"
  f2(ctx)
 }
 
 func f6() {
  f3() // want "Function `f3` should pass the context parameter"
 }
+
+func f7(ctx context.Context) {
+ ctx, cancel := getNewCtx(ctx)
+ defer cancel()
+
+ f2(ctx) // OK
+}
+
+func getNewCtx(ctx context.Context) (newCtx context.Context, cancel context.CancelFunc) {
+ return context.WithCancel(ctx)
+}