diff options
| author | Joël Stemmer <stemmertech@gmail.com> | 2015-02-02 12:01:08 +0100 |
|---|---|---|
| committer | Rob Pike <r@golang.org> | 2015-02-04 18:31:58 +0000 |
| commit | 913f41fc5f1b7afd8f7c66c011c1ad368fa23fb8 (patch) | |
| tree | 4c2048b0268ed2ef551d0d064355383389b5d3d0 | |
| parent | 0dda50d42a7564ec2d84149ab0ee90751d0dc589 (diff) | |
| download | tools-913f41fc5f1b7afd8f7c66c011c1ad368fa23fb8.tar.gz | |
cmd/vet: warn about zero arg index in print format
Argument indexes in a format string are one-based, however vet would not
warn when using a zero-index unless the type of the argument referenced
was not a string. That warning was misleading as it would say the type
was not a string. Vet will now print a correct warning when using a zero
index.
Included are tests for both cases.
Fixes #9752
Change-Id: I285e99990a86a653b4668b0c279d5f5f1c34f7aa
Reviewed-on: https://go-review.googlesource.com/3692
Reviewed-by: Rob Pike <r@golang.org>
| -rw-r--r-- | cmd/vet/print.go | 4 | ||||
| -rw-r--r-- | cmd/vet/testdata/print.go | 2 |
2 files changed, 6 insertions, 0 deletions
diff --git a/cmd/vet/print.go b/cmd/vet/print.go index 14de6ab..82edd81 100644 --- a/cmd/vet/print.go +++ b/cmd/vet/print.go @@ -474,6 +474,10 @@ func (f *File) argCanBeChecked(call *ast.CallExpr, formatArg int, isStar bool, s // Shouldn't happen, so catch it with prejudice. panic("negative arg num") } + if argNum == 0 { + f.Badf(call.Pos(), `index value [0] for %s("%s"); indexes start at 1`, state.name, state.format) + return false + } if argNum < len(call.Args)-1 { return true // Always OK. } diff --git a/cmd/vet/testdata/print.go b/cmd/vet/testdata/print.go index 3875ac5..22c6e0a 100644 --- a/cmd/vet/testdata/print.go +++ b/cmd/vet/testdata/print.go @@ -174,6 +174,8 @@ func PrintfTests() { Printf("%[3]*s", "hi", 2) // ERROR "missing argument for Printf.* reads arg 3, have only 2" fmt.Sprintf("%[3]d", 2) // ERROR "missing argument for Sprintf.* reads arg 3, have only 1" Printf("%[2]*.[1]*[3]d", 2, "hi", 4) // ERROR "arg .hi. for \* in printf format not of type int" + Printf("%[0]s", "arg1") // ERROR "index value \[0\] for Printf.*; indexes start at 1" + Printf("%[0]d", 1) // ERROR "index value \[0\] for Printf.*; indexes start at 1" // Something that satisfies the error interface. var e error fmt.Println(e.Error()) // ok |