Add go module & set import path to capnproto.org/go/capnp/v3

[lthibault]

Fixes #166.

• Add go.mod with import path as capnproto.org/go/capnp/v3
• Update import paths in all files

[lthibault]

$ go test ./...
--- FAIL: TestMarshalPackedShouldMatchTextWhenDecoded (0.14s)
    integration_test.go:762: zdataFilledMessage(20): decoded to:
        "(zdata = (data = \"\\000\\001\\002\\003\\004\\005\\006\\a\\b\\t\\n\\v\\f\\r\\016\\017\\020\\021\\022\\023\"))\n"; want:
        "(zdata = (data = \"\\x00\\x01\\x02\\x03\\x04\\x05\\x06\\a\\b\\t\\n\\v\\f\\r\\x0e\\x0f\\x10\\x11\\x12\\x13\"))\n"
--- FAIL: TestMarshalShouldMatchTextWhenDecoded (0.15s)
    integration_test.go:739: zdataFilledMessage(20): decoded to:
        "(zdata = (data = \"\\000\\001\\002\\003\\004\\005\\006\\a\\b\\t\\n\\v\\f\\r\\016\\017\\020\\021\\022\\023\"))\n"; want:
        "(zdata = (data = \"\\x00\\x01\\x02\\x03\\x04\\x05\\x06\\a\\b\\t\\n\\v\\f\\r\\x0e\\x0f\\x10\\x11\\x12\\x13\"))\n"
FAIL
FAIL    capnproto.org/go/capnp/v3       0.336s
--- FAIL: TestRemoteScope (0.00s)
    capnpc-go_test.go:217: different file struct: g.RemoteTypeName(nodes[0x836faf1834d91729].Const().Type(), nodes[0x836faf1834d91729]); g.imports = otherscopes "zombiezen.com/go/capnproto2/capnpc-go/testdata/otherscopes"; want otherscopes "capnproto.org/go/capnp/v3/capnpc-go/testdata/otherscopes"
    capnpc-go_test.go:217: different file struct list: g.RemoteTypeName(nodes[0x83e7e1b3cd1be338].Const().Type(), nodes[0x83e7e1b3cd1be338]); g.imports = otherscopes "zombiezen.com/go/capnproto2/capnpc-go/testdata/otherscopes"; want otherscopes "capnproto.org/go/capnp/v3/capnpc-go/testdata/otherscopes"
    capnpc-go_test.go:236: different file struct: g.RemoteTypeNew(nodes[0x836faf1834d91729].Const().Type(), nodes[0x836faf1834d91729]); g.imports = otherscopes "zombiezen.com/go/capnproto2/capnpc-go/testdata/otherscopes"; want otherscopes "capnproto.org/go/capnp/v3/capnpc-go/testdata/otherscopes"
    capnpc-go_test.go:236: different file struct list: g.RemoteTypeNew(nodes[0x83e7e1b3cd1be338].Const().Type(), nodes[0x83e7e1b3cd1be338]); g.imports = otherscopes "zombiezen.com/go/capnproto2/capnpc-go/testdata/otherscopes"; want otherscopes "capnproto.org/go/capnp/v3/capnpc-go/testdata/otherscopes"
FAIL
FAIL    capnproto.org/go/capnp/v3/capnpc-go     0.636s
FAIL

@zenhack Is this a known issue? (i.e. should I worry about it?)

[zenhack]

@lthibault, I think you forgot to re-generate some test data:

[isd@elf go-capnproto2]$ git grep zombiezen\.com/go
Binary file capnpc-go/testdata/aircraft.capnp.out matches
Binary file capnpc-go/testdata/const.capnp.out matches
Binary file capnpc-go/testdata/group.capnp.out matches
Binary file capnpc-go/testdata/rpc.capnp.out matches
Binary file capnpc-go/testdata/scopes.capnp.out matches
Binary file capnpc-go/testdata/util.capnp.out matches

[lthibault]

@lthibault, I think you forgot to re-generate some test data:

@zenhack Right on. What's the process for regenerating test data? I can't seem to find anything 🤔

[zenhack]

I'm not sure what the official way to regenerate those is; @zombiezen?

I assume they're just the output of capnp compile -o- /path/to/schema.capnp > schema.capnp.out, with appropriate flags.

[lthibault]

Alright, I've manually regenerated the test data for capnpc-go/testdata, and that seems to work well.

Concerning the errors in integration_test.go, the test data appears to be valid.

{
    name: "zdataFilledMessage(20)",
    msg:  zdataFilledMessage(t, 20),
    typ:  "Z",
    text: `(zdata = (data = "\x00\x01\x02\x03\x04\x05\x06\a\b\t\n\v\f\r\x0e\x0f\x10\x11\x12\x13"))` + "\n",
    data: []byte{
        0, 0, 0, 0, 9, 0, 0, 0,
        0, 0, 0, 0, 3, 0, 1, 0,
        28, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 0, 0,
        0, 0, 0, 0, 0, 0, 1, 0,
        1, 0, 0, 0, 162, 0, 0, 0,
	0, 1, 2, 3, 4, 5, 6, 7,
	8, 9, 10, 11, 12, 13, 14, 15,
	16, 17, 18, 19, 0, 0, 0, 0,
    },
},

Updating the text field appears to solve the issue.

Old: \x00\x01\x02\x03\x04\x05\x06\a\b\t\n\v\f\r\x0e\x0f\x10\x11\x12\x13
New: \000\001\002\003\004\005\006\a\b\t\n\v\f\r\016\017\020\021\022\023

I'm not sure I understand the root cause. Has Cap'n Proto's representation of binary data recently changed or something (I'm using versoin 0.8.0)?

[zenhack]

The text field is what the test expects capnp decode to output, so my guess is that at some point since this test was written, that command starting using octal escaping instead of hex when formatting (@kentonv?)

Anyway, LGTM.

[lthibault]

@zenhack Yeah, that was my instinct as well and I've managed to reproduce the output at the command line:

$ cat /tmp/zdataFilled20.out | capnp convert binary:text internal/aircraftlib/aircraft.capnp Z
( zdata = (
    data = "\000\001\002\003\004\005\006\a\b\t\n\v\f\r\016\017\020\021\022\023" ) )

Merging now. Thanks for your help!

[kentonv]

Looks like the switch from hex to octal happened here: capnproto/capnproto@03800df

Looks like it was not entirely advertent. But, hex escapes do have the drawback that in many languages (including C/C++), they are technically not limited to two digits, and so a string like "\x012" is technically equivalent to "\x12". This makes it really hard to output an arbitrary string with hex escapes correctly, since any valid hex digit appearing immediately after an escape has to be escaped, too. Octal escapes, on the other hand, are never more than three digits, so that's much easier to deal with.