From 20c10da9027bad9d852ae23374cb8d25d7ecb745 Mon Sep 17 00:00:00 2001
From: sylvia7788 <1227977886@qq.com>
Date: Sat, 4 Sep 2021 16:28:08 +0800
Subject: [PATCH] modify prompt

---
 README.md           | 17 +++++++++++++----
 contextcheck.go     |  8 ++++----
 testdata/src/a/a.go | 17 ++++++++++++++---
 3 files changed, 31 insertions(+), 11 deletions(-)

diff --git a/README.md b/README.md
index 9ab5a42..dc951ac 100644
--- a/README.md
+++ b/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` ./...
 ```
diff --git a/contextcheck.go b/contextcheck.go
index eaf770d..543a802 100644
--- a/contextcheck.go
+++ b/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,
@@ -247,7 +247,7 @@ 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
 		}
 	}
@@ -255,7 +255,7 @@ func (r *runner) collectCtxRef(f *ssa.Function) (refMap map[ssa.Instruction]bool
 	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")
 				}
 			}
 
diff --git a/testdata/src/a/a.go b/testdata/src/a/a.go
index e864b83..3ae0dba 100644
--- a/testdata/src/a/a.go
+++ b/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)
@@ -63,7 +63,7 @@ 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) {
@@ -71,10 +71,21 @@ func f5(ctx context.Context) {
 		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)
+}