cmd/go: go clean should not accept flags like -modcache with packages

For #53725

Change-Id: I99a85b437d5f918dba74c4eccefcf8087193646a
Reviewed-on: https://go-review.googlesource.com/c/go/+/425874
Run-TryBot: Bryan Mills <bcmills@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Bryan Mills <bcmills@google.com>

src/cmd/go/internal/clean/clean.go

@@ -118,6 +118,23 @@ func init() {
 }
 
 func runClean(ctx context.Context, cmd *base.Command, args []string) {
+	if len(args) > 0 {
+		cacheFlag := ""
+		switch {
+		case cleanCache:
+			cacheFlag = "-cache"
+		case cleanTestcache:
+			cacheFlag = "-testcache"
+		case cleanFuzzcache:
+			cacheFlag = "-fuzzcache"
+		case cleanModcache:
+			cacheFlag = "-modcache"
+		}
+		if cacheFlag != "" {
+			base.Fatalf("go: clean %s cannot be used with package arguments", cacheFlag)
+		}
+	}
+
 	// golang.org/issue/29925: only load packages before cleaning if
 	// either the flags and arguments explicitly imply a package,
 	// or no other target (such as a cache) was requested to be cleaned.

src/cmd/go/testdata/script/clean_cache_n.txt

@@ -15,6 +15,9 @@ exists $GOCACHE/00
 go clean -cache
 ! exists $GOCACHE/00
 
+! go clean -cache .
+stderr 'go: clean -cache cannot be used with package arguments'
+
 -- main.go --
 package main
 

src/cmd/go/testdata/script/clean_testcache.txt

@@ -8,6 +8,8 @@ go test x_test.go
 go clean -testcache
 go test x_test.go
 ! stdout 'cached'
+! go clean -testcache ../x
+stderr 'go: clean -testcache cannot be used with package arguments'
 
 # golang.org/issue/29100: 'go clean -testcache' should succeed
 # if the cache directory doesn't exist at all.

src/cmd/go/testdata/script/mod_clean_cache.txt

@@ -35,6 +35,9 @@ go clean -modcache
 ! stderr 'finding rsc.io'
 go mod edit -droprequire rsc.io/quote
 
+! go clean -modcache m
+stderr 'go: clean -modcache cannot be used with package arguments'
+
 -- go.mod --
 module m
 -- m.go --

src/cmd/go/testdata/script/test_fuzz_cache.txt

@@ -37,6 +37,9 @@ go test -fuzz=FuzzEmpty -fuzztime=2x .
 stdout 'new interesting: 0'
 stdout 'total: 1'
 
+! go clean -fuzzcache example.com/y
+stderr 'go: clean -fuzzcache cannot be used with package arguments'
+
 -- go.mod --
 module example.com/y