cmd/vet: ignore unrecognized verbs for fmt.Formatter
Updates #17057.
Change-Id: I54c838d3a44007d4023754e42971e91bfb5e8612
Reviewed-on: https://go-review.googlesource.com/32851
Run-TryBot: Rob Pike <r@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
diff --git a/src/cmd/vet/print.go b/src/cmd/vet/print.go
index df8e57e..9998dda 100644
--- a/src/cmd/vet/print.go
+++ b/src/cmd/vet/print.go
@@ -192,6 +192,12 @@
f.pkg.types[d.Type.Results.List[0].Type].Type == types.Typ[types.String]
}
+// isFormatter reports whether t satisfies fmt.Formatter.
+// Unlike fmt.Stringer, it's impossible to satisfy fmt.Formatter without importing fmt.
+func (f *File) isFormatter(t types.Type) bool {
+ return formatterType != nil && types.Implements(t, formatterType)
+}
+
// formatState holds the parsed representation of a printf directive such as "%3.*[4]d".
// It is constructed by parsePrintfVerb.
type formatState struct {
@@ -423,8 +429,6 @@
)
// printVerbs identifies which flags are known to printf for each verb.
-// TODO: A type that implements Formatter may do what it wants, and vet
-// will complain incorrectly.
var printVerbs = []printVerb{
// '-' is a width modifier, always valid.
// '.' is a precision for float, max width for strings.
@@ -466,7 +470,16 @@
break
}
}
- if !found {
+
+ // Does current arg implement fmt.Formatter?
+ formatter := false
+ if state.argNum < len(call.Args) {
+ if tv, ok := f.pkg.types[call.Args[state.argNum]]; ok {
+ formatter = f.isFormatter(tv.Type)
+ }
+ }
+
+ if !found && !formatter {
f.Badf(call.Pos(), "unrecognized printf verb %q", state.verb)
return false
}
@@ -494,7 +507,7 @@
return false
}
}
- if state.verb == '%' {
+ if state.verb == '%' || formatter {
return true
}
argNum := state.argNums[len(state.argNums)-1]
