database/sql: sql argument counts are off by one when reporting an error

[lpar]

I know this is pretty trivial, but when reporting an error the sql package seems to report arguments by counting them starting at zero.

Since SQL arguments are generally numbered from 1 -- and indeed, for PostgreSQL they are numbered $1, $2, $3... in the SQL itself -- this confused me.

e.g. sql: converting Exec argument #3's type: unsupported type main.Date, a struct
It was actually argument #4 ($4 in the SQL statement).

go version go1.6.2 linux/amd64

GOARCH="amd64"
GOBIN=""
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOOS="linux"
GOPATH="/home/meta/go/tecdocs"
GORACE=""
GOROOT="/usr/local/go"
GOTOOLDIR="/usr/local/go/pkg/tool/linux_amd64"
GO15VENDOREXPERIMENT="1"
CC="gcc"
GOGCCFLAGS="-fPIC -m64 -pthread -fmessage-length=0"
CXX="g++"
CGO_ENABLED="1"

[quentinmit]

I suspect any changes we make at this point are just going to make things even more confusing, unfortunately. Would dropping the "#" prefix make you less likely to think they're 1-based?

/cc @bradfitz ?

[kardianos]

I'm of the opinion we should ensure all parameters are referenced by ordinal, not index.

[bradfitz]

@kardianos, you mean you advocate for a change, rather than documenting the status quo?

[kardianos]

Yes, I would change the message to ensure all parameters match the ordinal position. Simply being SQL is reason enough to think they are 1-based references (ordinal not index).

[bradfitz]

Sure. We can change it if everybody agrees. Should we preface them all by '$' then? Is that more clear?

[gopherbot]

CL https://golang.org/cl/31262 mentions this issue.

[lpar]

How about keeping # as the prefix for 0-indexed, but deprecating it; and introducing $ as the prefix for 1-indexed? That'd presumably not break anyone's code unexpectedly, and then everyone could have until Go 1.9 to switch over.

[kardianos]

@lpar What do you think of the CL https://golang.org/cl/31262 ? I hope no one is trying to parse the error message mechanically, but if they are, I can include it in a general announcement in a week or two.

[lpar]

I think the improved message would at least have eliminated my confusion after the fact.