panic with sql:"-" field set

[Tommy-42]

Hello,

I am using golang/protobuf in one of my project which has an older version that another one that I am currently working on ( which has the very last one ).

For some reason, they implemented some "breaking change" to the generated code ( they add 3 more fields to the generated struct.

for example :

message User {
  string id = 1;
  string username = 2;
}

generated :

type User struct {
	Id                   string           `protobuf:"bytes,1,opt,name=id,proto3" json:"id,omitempty"`
	Username             string           `protobuf:"bytes,2,opt,name=username,proto3" json:"username,omitempty"`
}

but now generates :

type User struct {
	Id                   string           `protobuf:"bytes,1,opt,name=id,proto3" json:"id,omitempty"`
	Username             string           `protobuf:"bytes,2,opt,name=username,proto3" json:"username,omitempty"`
	XXX_NoUnkeyedLiteral struct{}         `json:"-"`
	XXX_unrecognized     []byte           `json:"-"`
	XXX_sizecache        int32            `json:"-"`
}

So you may start understanding what problem it could cause with go-pg ... :(

I do have found a way to append sql:"-" tag with github.com/favadi/protoc-go-inject-tag
to the struct

	XXX_NoUnkeyedLiteral struct{}         `json:"-" sql:"-"`
	XXX_unrecognized     []byte           `json:"-" sql:"-"`
	XXX_sizecache        int32            `json:"-" sql:"-"`
}

but when I do :

err = s.DB.Model(user).Where("username = ?", req.Username).Select()

I've got a panic :

panic: reflect: call of reflect.Value.Field on zero Value [recovered]
	panic: reflect: call of reflect.Value.Field on zero Value

goroutine 21 [running]:
testing.tRunner.func1(0xc4200fef00)
	/usr/local/Cellar/go/1.10/libexec/src/testing/testing.go:742 +0x29d
panic(0x15aa680, 0xc4200c98c0)
	/usr/local/Cellar/go/1.10/libexec/src/runtime/panic.go:505 +0x229
reflect.Value.Field(0x0, 0x0, 0x0, 0x0, 0xc4201fcd70, 0x2, 0xc420114000)
	/usr/local/Cellar/go/1.10/libexec/src/reflect/value.go:782 +0x11b
myrepo/vendor/github.com/go-pg/pg/orm.fieldByIndex(0x0, 0x0, 0x0, 0xc4201fc3e8, 0x1, 0x1, 0x166b705, 0x2, 0xc4200bb3f0)
	myrepo/vendor/github.com/go-pg/pg/orm/util.go:54 +0x4c
myrepo/vendor/github.com/go-pg/pg/orm.(*Field).ScanValue(0xc4200de120, 0x0, 0x0, 0x0, 0xc420114000, 0x24, 0x200, 0x16d5280, 0xc4200ca0c0)
	myrepo/vendor/github.com/go-pg/pg/orm/field.go:86 +0x6c
myrepo/vendor/github.com/go-pg/pg/orm.(*structTableModel).scanColumn(0xc420174100, 0x0, 0xc4201fcd70, 0x2, 0xc420114000, 0x24, 0x200, 0x24, 0x0, 0x0)
	myrepo/vendor/github.com/go-pg/pg/orm/model_table_struct.go:237 +0x123
myrepo/vendor/github.com/go-pg/pg/orm.(*structTableModel).ScanColumn(0xc420174100, 0x0, 0xc4201fcd70, 0x2, 0xc420114000, 0x24, 0x200, 0x200, 0x0)
	myrepo/vendor/github.com/go-pg/pg/orm/model_table_struct.go:199 +0x8e
myrepo/vendor/github.com/go-pg/pg.readDataRow(0xc420128000, 0x16d5600, 0xc420174100, 0xc420240120, 0x6, 0x6, 0x6, 0x0)
	myrepo/vendor/github.com/go-pg/pg/messages.go:590 +0x15f
myrepo/vendor/github.com/go-pg/pg.readSimpleQueryData(0xc420128000, 0x16577a0, 0xc420174100, 0x1617760, 0xc4200c9760, 0xc4200ab050)
	myrepo/vendor/github.com/go-pg/pg/messages.go:636 +0x25e
myrepo/vendor/github.com/go-pg/pg.(*DB).simpleQueryData(0xc4201bc230, 0xc420128000, 0x16577a0, 0xc420174100, 0x1617760, 0xc4200c9760, 0xc4200ab050, 0x1, 0x1, 0x1d, ...)
	myrepo/vendor/github.com/go-pg/pg/db.go:469 +0xe0
myrepo/vendor/github.com/go-pg/pg.(*DB).Query(0xc4201bc230, 0x16577a0, 0xc420174100, 0x1617760, 0xc4200c9760, 0xc4200ab050, 0x1, 0x1, 0xc420069d48, 0x1012a98, ...)
	myrepo/vendor/github.com/go-pg/pg/db.go:256 +0x170
myrepo/vendor/github.com/go-pg/pg.(*DB).QueryOne(0xc4201bc230, 0x16577a0, 0xc420174100, 0x1617760, 0xc4200c9760, 0xc4200ab050, 0x1, 0x1, 0xc420069dd0, 0x100feaf, ...)
	myrepo/vendor/github.com/go-pg/pg/db.go:281 +0x8d
myrepo/vendor/github.com/go-pg/pg/orm.(*Query).query(0xc420095680, 0x16e0000, 0xc420174100, 0x1617760, 0xc4200c9760, 0xc420174100, 0x0, 0x0, 0xc4200b70c0)
	myrepo/vendor/github.com/go-pg/pg/orm/query.go:622 +0x12d
myrepo/vendor/github.com/go-pg/pg/orm.(*Query).Select(0xc420095680, 0x0, 0x0, 0x0, 0x1, 0x1)
	myrepo/vendor/github.com/go-pg/pg/orm/query.go:594 +0xf9
myrepo/service/users/v0.(*Service).AuthenticateUser(0xc4200c2678, 0x16dc480, 0xc4200b4048, 0xc4200b79c0, 0x10e60fd, 0x17a8108, 0xc420045798)
	myrepo/service/users/v0/users.go:49 +0x2b1
myrepo/service/users/v0.TestAuthenticateUser.func1(0xc4200fef00)
	myrepo/service/users/v0/users_test.go:104 +0x64
testing.tRunner(0xc4200fef00, 0xc420232460)
	/usr/local/Cellar/go/1.10/libexec/src/testing/testing.go:777 +0xd0
created by testing.(*T).Run
	/usr/local/Cellar/go/1.10/libexec/src/testing/testing.go:824 +0x2e0

the panic happens when I add sql:"-" to the struct, If I remove it, I have the famous
ERROR #42703 column user.xxx__no_unkeyed_literal does not exist (addr="127.0.0.1:5432")

do you have an idea on how to resolve this ?

I may have done something wrong ...

thanks for your help

[vmihailenco]

Hi,

I can't reproduce this on latest master. Can you to upgrade go-pg and create a reproducer?

[Tommy-42]

Hi, dep init has set up a specific version

 [[constraint]]
  name = "github.com/go-pg/pg"
  version = "6.14.3"

I will try on master branch and if I do have the same behavior, I will try to setup a reproducer

[Tommy-42]

After updating, It works, I no longer have the panic.

Thanks

[Tommy-42]

Arf mybad, I did it too fast, my db was empty so no data were found, after adding some data, it actually fails again :/ I will try to set up a reproducer

[Tommy-42]

https://github.com/Tommy-42/go-pg-error-reproducer

It should fail with the same error

[vmihailenco]

I will fix the panic by returning an error, but overall you should initialize the user on https://github.com/Tommy-42/go-pg-error-reproducer/blob/master/main.go#L47, e.g. via user := new(User).