Use yaml.v3 instead of modified yaml.v2 for handling YAML files (#791)

* Add another test (that currently fails).

* First shot at using yaml.v3 for reading YAML files with comments.

* Allow parsing multi-document YAML files.

* Use Decoder to parse multi-part documents.

* Use yaml.v3 for config and audit.

* First step of serializing YAML using yaml.v3.

* Always serialize with yaml.v3.

* Remove debug prints.

* Remove traces of github.com/mozilla-services/yaml.

* Improve serialization of documents consisting only of comments.

* Improve handling of some empty documents.

* Adjust to latest changes in go-yaml/yaml#684.

* Bump yaml.v3 version, temporarily disable failing tests.

* Run go mod tidy.

* Fix CI.

audit/audit.go

@@ -12,7 +12,7 @@ import (
 	// empty import as per https://godoc.org/github.com/lib/pq
 	_ "github.com/lib/pq"
 
-	"github.com/mozilla-services/yaml"
+	"gopkg.in/yaml.v3"
 	"github.com/sirupsen/logrus"
 	"go.mozilla.org/sops/v3/logging"
 )

config/config.go

@@ -10,7 +10,7 @@ import (
 	"path"
 	"regexp"
 
-	"github.com/mozilla-services/yaml"
+	"gopkg.in/yaml.v3"
 	"github.com/sirupsen/logrus"
 	"go.mozilla.org/sops/v3"
 	"go.mozilla.org/sops/v3/age"

go.mod

@@ -30,7 +30,6 @@ require (
 	github.com/lib/pq v1.2.0
 	github.com/mitchellh/go-homedir v1.1.0
 	github.com/mitchellh/go-wordwrap v1.0.0
-	github.com/mozilla-services/yaml v0.0.0-20201007153854-c369669a6625
 	github.com/opencontainers/go-digest v1.0.0-rc1 // indirect
 	github.com/opencontainers/image-spec v1.0.1 // indirect
 	github.com/opencontainers/runc v0.1.1 // indirect
@@ -49,5 +48,6 @@ require (
 	google.golang.org/protobuf v1.25.0
 	gopkg.in/ini.v1 v1.44.0
 	gopkg.in/urfave/cli.v1 v1.20.0
+	gopkg.in/yaml.v3 v3.0.0-20210107172259-749611fa9fcc
 	gotest.tools v2.2.0+incompatible // indirect
 )

go.sum

@@ -201,8 +201,6 @@ github.com/mitchellh/go-wordwrap v1.0.0/go.mod h1:ZXFpozHsX6DPmq2I0TCekCxypsnAUb
 github.com/mitchellh/mapstructure v1.1.2 h1:fmNYVwqnSfB9mZU6OS2O6GsXM+wcskZDuKQzvN1EDeE=
 github.com/mitchellh/mapstructure v1.1.2/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y=
 github.com/mitchellh/reflectwalk v1.0.0/go.mod h1:mSTlrgnPZtwu0c4WaC2kGObEpuNDbx0jmZXqmk4esnw=
-github.com/mozilla-services/yaml v0.0.0-20201007153854-c369669a6625 h1:5IeGQzguDQ+EsTR5HE7tMYkZe09mqQ9cDypdKQEB5Kg=
-github.com/mozilla-services/yaml v0.0.0-20201007153854-c369669a6625/go.mod h1:Is/Ucts/yU/mWyGR8yELRoO46mejouKsJfQLAIfTR18=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/oklog/run v1.0.0/go.mod h1:dlhp/R75TPv97u0XWUtDeV/lRKWPKSdTuV0TZvrmrQA=
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
@@ -410,6 +408,8 @@ gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.4 h1:/eiJrUcujPVeJ3xlSWaiNi3uSVmDGBK1pDHUHAnao1I=
 gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v3 v3.0.0-20210107172259-749611fa9fcc h1:XANm4xAMEQhRdWKqaL0qmhGDv7RuobwCO97TIlktaQE=
+gopkg.in/yaml.v3 v3.0.0-20210107172259-749611fa9fcc/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gotest.tools v2.2.0+incompatible h1:VsBPFP1AI068pPrMxtb/S8Zkgf9xEmTLJjfM+P5UIEo=
 gotest.tools v2.2.0+incompatible/go.mod h1:DsYFclhRJ6vuDpmuTbkuFWG+y2sxOXAzmJt81HFBacw=
 honnef.co/go/tools v0.0.0-20180728063816-88497007e858/go.mod h1:rf3lG4BRIbNafJWhAfAdb/ePZxsR/4RtNHQocxwk9r4=