Fixed linting

Dockerfile

@@ -21,3 +21,5 @@ ARG VERSION=none
 LABEL version=${VERSION}
 
 WORKDIR /workdir
+
+ENTRYPOINT [/usr/bin/yq]

cmd/constant.go

@@ -1,13 +1,11 @@
 package cmd
 
-import (
-	logging "gopkg.in/op/go-logging.v1"
-)
-
 var unwrapScalar = true
-var writeInplace = false
+
+// var writeInplace = false
 var outputToJSON = false
-var exitStatus = false
+
+// var exitStatus = false
 var forceColor = false
 var forceNoColor = false
 var colorsEnabled = false
@@ -17,4 +15,5 @@ var nullInput = false
 var verbose = false
 var version = false
 var shellCompletion = ""
-var log = logging.MustGetLogger("yq")
+
+// var log = logging.MustGetLogger("yq")

cmd/evaluate_all_command.go

@@ -11,13 +11,13 @@ func createEvaluateAllCommand() *cobra.Command {
 	var cmdEvalAll = &cobra.Command{
 		Use:     "eval-all [expression] [yaml_file1]...",
 		Aliases: []string{"ea"},
-		Short:   "Loads all yaml documents of all yaml files and runs expression once",
+		Short:   "Loads _all_ yaml documents of _all_ yaml files and runs expression once",
 		Example: `
 yq es '.a.b | length' file1.yml file2.yml
 yq es < sample.yaml
 yq es -n '{"a": "b"}'
 `,
-		Long: "Evaluate All:\nUseful when you need to run an expression across several yaml documents or files. Consumes more memory than eval-seq",
+		Long: "Evaluate All:\nUseful when you need to run an expression across several yaml documents or files. Consumes more memory than eval",
 		RunE: evaluateAll,
 	}
 	return cmdEvalAll
@@ -56,7 +56,7 @@ func evaluateAll(cmd *cobra.Command, args []string) error {
 			err = yqlib.EvaluateAllFileStreams("", []string{args[0]}, printer)
 		}
 	default:
-		err = yqlib.EvaluateAllFileStreams(args[0], args[1:len(args)], printer)
+		err = yqlib.EvaluateAllFileStreams(args[0], args[1:], printer)
 	}
 
 	cmd.SilenceUsage = true

cmd/evalute_sequence_command.go

@@ -9,8 +9,8 @@ import (
 
 func createEvaluateSequenceCommand() *cobra.Command {
 	var cmdEvalSequence = &cobra.Command{
-		Use:     "eval-seq [expression] [yaml_file1]...",
+		Use:     "eval [expression] [yaml_file1]...",
-		Aliases: []string{"es"},
+		Aliases: []string{"e"},
 		Short:   "Apply expression to each document in each yaml file given in sequence",
 		Example: `
 yq es '.a.b | length' file1.yml file2.yml
@@ -56,7 +56,7 @@ func evaluateSequence(cmd *cobra.Command, args []string) error {
 			err = yqlib.EvaluateFileStreamsSequence("", []string{args[0]}, printer)
 		}
 	default:
-		err = yqlib.EvaluateFileStreamsSequence(args[0], args[1:len(args)], printer)
+		err = yqlib.EvaluateFileStreamsSequence(args[0], args[1:], printer)
 	}
 
 	cmd.SilenceUsage = true

go.mod

@@ -5,14 +5,12 @@ require (
 	github.com/fatih/color v1.9.0
 	github.com/goccy/go-yaml v1.8.1
 	github.com/jinzhu/copier v0.0.0-20190924061706-b57f9002281a
-	github.com/kylelemons/godebug v1.1.0 // indirect
 	github.com/mattn/go-colorable v0.1.7 // indirect
-	github.com/pkg/errors v0.9.1 // indirect
 	github.com/spf13/cobra v1.0.0
 	github.com/spf13/pflag v1.0.5 // indirect
 	github.com/timtadh/data-structures v0.5.3 // indirect
 	github.com/timtadh/lexmachine v0.2.2
-	golang.org/x/sys v0.0.0-20200905004654-be1d3432aa8f // indirect
+	golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f // indirect
 	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
 	gopkg.in/op/go-logging.v1 v1.0.0-20160211212156-b2cb9fa56473
 	gopkg.in/yaml.v3 v3.0.0-20200615113413-eeeca48fe776

go.sum

@@ -15,6 +15,7 @@ github.com/coreos/go-systemd v0.0.0-20190321100706-95778dfbb74e/go.mod h1:F5haX7
 github.com/coreos/pkg v0.0.0-20180928190104-399ea9e2e55f/go.mod h1:E3G3o1h8I7cfcXa63jLwjI0eiQQMgzzUDFVpN/nH/eA=
 github.com/cpuguy83/go-md2man/v2 v2.0.0/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/dgrijalva/jwt-go v3.2.0+incompatible/go.mod h1:E3ru+11k8xSBh+hMPgOLZmtrrCbhqsmaPHjLKYnJCaQ=
 github.com/dgryski/go-sip13 v0.0.0-20181026042036-e10d5fee7954/go.mod h1:vAd38F8PWV+bWy6jNmig1y/TA+kYO4g3RSRF0IAv0no=
@@ -62,8 +63,6 @@ github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORN
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
-github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
-github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/leodido/go-urn v1.2.0/go.mod h1:+8+nEpDfqqsY+g338gtMEUOtuK+4dEMhiQEgxpxOKII=
 github.com/magiconair/properties v1.8.0/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
 github.com/mattn/go-colorable v0.1.4 h1:snbPLB8fVfU9iwbbo30TPtbLRzwWu6aJS6Xh4eaaviA=
@@ -77,18 +76,13 @@ github.com/mattn/go-isatty v0.0.11/go.mod h1:PhnuNfih5lzO57/f3n+odYbM4JtupLOxQOA
 github.com/mattn/go-isatty v0.0.12 h1:wuysRhFDzyxgEmMf5xjvJ2M9dZoWAXNNr5LSBS7uHXY=
 github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
 github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
-github.com/mikefarah/yq v1.15.0 h1:ViMYNRG5UB7hzm8olxMFqPtkpMXXKO4g32/v9JUa62o=
-github.com/mikefarah/yq v2.4.0+incompatible h1:oBxbWy8R9hI3BIUUxEf0CzikWa2AgnGrGhvGQt5jgjk=
-github.com/mikefarah/yq/v3 v3.0.0-20201020025845-ccb718cd0f59 h1:6nvF+EEFIVD4KT64CgvAzWaMVC283Huno59khWs9r1A=
-github.com/mikefarah/yq/v3 v3.0.0-20201020025845-ccb718cd0f59/go.mod h1:7eVjFf5bgozMuHk+oKpyxR2zCN3iEN1tF0/bM5jvtKo=
 github.com/mitchellh/go-homedir v1.1.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrkLzIz1N1q0pr0=
 github.com/mitchellh/mapstructure v1.1.2/go.mod h1:FVVH3fgwuzCH5S8UJGiWEs2h04kUh9fWfEaFds41c1Y=
 github.com/mwitkow/go-conntrack v0.0.0-20161129095857-cc309e4a2223/go.mod h1:qRWi+5nqEBWmkhHvq77mSJWrCKwh8bxhgT7d/eI7P4U=
 github.com/oklog/ulid v1.3.1/go.mod h1:CirwcVhetQ6Lv90oh/F+FBtV6XMibvdAFo93nm5qn4U=
 github.com/pelletier/go-toml v1.2.0/go.mod h1:5z9KED0ma1S8pY6P1sdut58dfprrGBbd/94hg7ilaic=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
-github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
-github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_golang v0.9.1/go.mod h1:7SWBe2y4D6OKWSNQJUaRYU/AaXPKyh/dDVn+NZz0KFw=
 github.com/prometheus/client_golang v0.9.3/go.mod h1:/TN21ttK/J9q6uSwhBd54HahCDft0ttaMvbicHlPoso=
@@ -118,6 +112,7 @@ github.com/spf13/viper v1.4.0/go.mod h1:PTJ7Z/lr49W6bUbkmS1V3by4uWynFiR9p7+dSq/y
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
+github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk=
 github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
 github.com/timtadh/data-structures v0.5.3 h1:F2tEjoG9qWIyUjbvXVgJqEOGJPMIiYn7U5W5mE+i/vQ=
 github.com/timtadh/data-structures v0.5.3/go.mod h1:9R4XODhJ8JdWFEI8P/HJKqxuJctfBQw6fDibMQny2oU=
@@ -156,8 +151,8 @@ golang.org/x/sys v0.0.0-20191026070338-33540a1f6037 h1:YyJpGZS1sBuBCzLAR1VEpK193
 golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200116001909-b77594299b42/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20200223170610-d5e6a3e2c0ae/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20200905004654-be1d3432aa8f h1:Fqb3ao1hUmOR3GkUOg/Y+BadLwykBIzs5q8Ez2SbHyc=
+golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f h1:+Nyd8tzPX9R7BWHguqsrbFdRx3WQ/1ib8I44HXV5yTA=
-golang.org/x/sys v0.0.0-20200905004654-be1d3432aa8f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.2/go.mod h1:bEr9sfX3Q8Zfm5fL9x+3itogRgK3+ptLWKqgva+5dAk=
 golang.org/x/time v0.0.0-20190308202827-9d24e82272b4/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=

pkg/yqlib/candidate_node.go

@@ -20,10 +20,13 @@ func (n *CandidateNode) GetKey() string {
 	return fmt.Sprintf("%v - %v", n.Document, n.Path)
 }
 
-func (n *CandidateNode) Copy() *CandidateNode {
+func (n *CandidateNode) Copy() (*CandidateNode, error) {
 	clone := &CandidateNode{}
-	copier.Copy(clone, n)
+	err := copier.Copy(clone, n)
-	return clone
+	if err != nil {
+		return nil, err
+	}
+	return clone, nil
 }
 
 // updates this candidate from the given candidate node

pkg/yqlib/operator_collect_object.go

@@ -83,10 +83,14 @@ func collect(d *dataTreeNavigator, aggregate *list.List, remainingMatches *list.
 		aggCandidate := el.Value.(*CandidateNode)
 		for splatEl := splatted.Front(); splatEl != nil; splatEl = splatEl.Next() {
 			splatCandidate := splatEl.Value.(*CandidateNode)
-			newCandidate := aggCandidate.Copy()
+			newCandidate, err := aggCandidate.Copy()
+			if err != nil {
+				return nil, err
+			}
+
 			newCandidate.Path = nil
 
-			newCandidate, err := multiply(d, newCandidate, splatCandidate)
+			newCandidate, err = multiply(d, newCandidate, splatCandidate)
 			if err != nil {
 				return nil, err
 			}

pkg/yqlib/operator_explode.go

@@ -18,7 +18,10 @@ func ExplodeOperator(d *dataTreeNavigator, matchMap *list.List, pathNode *PathTr
 			return nil, err
 		}
 		for childEl := rhs.Front(); childEl != nil; childEl = childEl.Next() {
-			explodeNode(childEl.Value.(*CandidateNode).Node)
+			err = explodeNode(childEl.Value.(*CandidateNode).Node)
+			if err != nil {
+				return nil, err
+			}
 		}
 
 	}
@@ -65,11 +68,17 @@ func explodeNode(node *yaml.Node) error {
 					log.Debugf("an alias merge list!")
 					for index := 0; index < len(valueNode.Content); index = index + 1 {
 						aliasNode := valueNode.Content[index]
-						applyAlias(node, aliasNode.Alias, index, newContent)
+						err := applyAlias(node, aliasNode.Alias, index, newContent)
+						if err != nil {
+							return err
+						}
 					}
 				} else {
 					log.Debugf("an alias merge!")
-					applyAlias(node, valueNode.Alias, index, newContent)
+					err := applyAlias(node, valueNode.Alias, index, newContent)
+					if err != nil {
+						return err
+					}
 				}
 			}
 		}

pkg/yqlib/operator_multilpy.go

@@ -72,7 +72,10 @@ func multiply(d *dataTreeNavigator, lhs *CandidateNode, rhs *CandidateNode) (*Ca
 
 func mergeObjects(d *dataTreeNavigator, lhs *CandidateNode, rhs *CandidateNode) (*CandidateNode, error) {
 	var results = list.New()
-	recursiveDecent(d, results, nodeToMap(rhs))
+	err := recursiveDecent(d, results, nodeToMap(rhs))
+	if err != nil {
+		return nil, err
+	}
 
 	var pathIndexToStartFrom int = 0
 	if results.Front() != nil {

pkg/yqlib/operator_traverse_path.go

@@ -136,7 +136,10 @@ func traverseMap(newMatches *orderedmap.OrderedMap, candidate *CandidateNode, op
 		//skip the 'merge' tag, find a direct match first
 		if key.Tag == "!!merge" && followAlias {
 			log.Debug("Merge anchor")
-			traverseMergeAnchor(newMatches, candidate, value, operation)
+			err := traverseMergeAnchor(newMatches, candidate, value, operation)
+			if err != nil {
+				return err
+			}
 		} else if keyMatches(key, operation) {
 			log.Debug("MATCHED")
 			candidateNode := &CandidateNode{
@@ -151,7 +154,7 @@ func traverseMap(newMatches *orderedmap.OrderedMap, candidate *CandidateNode, op
 	return nil
 }
 
-func traverseMergeAnchor(newMatches *orderedmap.OrderedMap, originalCandidate *CandidateNode, value *yaml.Node, operation *Operation) {
+func traverseMergeAnchor(newMatches *orderedmap.OrderedMap, originalCandidate *CandidateNode, value *yaml.Node, operation *Operation) error {
 	switch value.Kind {
 	case yaml.AliasNode:
 		candidateNode := &CandidateNode{
@@ -159,13 +162,16 @@ func traverseMergeAnchor(newMatches *orderedmap.OrderedMap, originalCandidate *C
 			Path:     originalCandidate.Path,
 			Document: originalCandidate.Document,
 		}
-		traverseMap(newMatches, candidateNode, operation)
+		return traverseMap(newMatches, candidateNode, operation)
 	case yaml.SequenceNode:
 		for _, childValue := range value.Content {
-			traverseMergeAnchor(newMatches, originalCandidate, childValue, operation)
+			err := traverseMergeAnchor(newMatches, originalCandidate, childValue, operation)
+			if err != nil {
+				return err
+			}
 		}
 	}
-	return
+	return nil
 }
 
 func traverseArray(candidate *CandidateNode, operation *Operation) ([]*CandidateNode, error) {

pkg/yqlib/operators_test.go

@@ -48,6 +48,13 @@ func testScenario(t *testing.T, s *expressionScenario) {
 	test.AssertResultComplexWithContext(t, s.expected, resultsToString(results), fmt.Sprintf("exp: %v\ndoc: %v", s.expression, s.document))
 }
 
+func writeOrPanic(w *bufio.Writer, text string) {
+	_, err := w.WriteString(text)
+	if err != nil {
+		panic(err)
+	}
+}
+
 func documentScenarios(t *testing.T, title string, scenarios []expressionScenario) {
 	f, err := os.Create(fmt.Sprintf("doc/%v.md", title))
 
@@ -56,27 +63,27 @@ func documentScenarios(t *testing.T, title string, scenarios []expressionScenari
 	}
 	defer f.Close()
 	w := bufio.NewWriter(f)
-	w.WriteString(fmt.Sprintf("# %v\n", title))
+	writeOrPanic(w, fmt.Sprintf("# %v\n", title))
-	w.WriteString(fmt.Sprintf("## Examples\n"))
+	writeOrPanic(w, "## Examples\n")
 
 	for index, s := range scenarios {
 		if !s.skipDoc {
 
 			if s.description != "" {
-				w.WriteString(fmt.Sprintf("### %v\n", s.description))
+				writeOrPanic(w, fmt.Sprintf("### %v\n", s.description))
 			} else {
-				w.WriteString(fmt.Sprintf("### Example %v\n", index))
+				writeOrPanic(w, fmt.Sprintf("### Example %v\n", index))
 			}
 			if s.document != "" {
-				w.WriteString(fmt.Sprintf("sample.yml:\n"))
+				writeOrPanic(w, "sample.yml:\n")
-				w.WriteString(fmt.Sprintf("```yaml\n%v\n```\n", s.document))
+				writeOrPanic(w, fmt.Sprintf("```yaml\n%v\n```\n", s.document))
 			}
 			if s.expression != "" {
-				w.WriteString(fmt.Sprintf("Expression\n"))
+				writeOrPanic(w, "Expression\n")
-				w.WriteString(fmt.Sprintf("```bash\nyq '%v' < sample.yml\n```\n", s.expression))
+				writeOrPanic(w, fmt.Sprintf("```bash\nyq '%v' < sample.yml\n```\n", s.expression))
 			}
 
-			w.WriteString(fmt.Sprintf("Result\n"))
+			writeOrPanic(w, "Result\n")
 
 			var output bytes.Buffer
 			var err error
@@ -88,15 +95,18 @@ func documentScenarios(t *testing.T, title string, scenarios []expressionScenari
 					t.Error(err)
 				}
 				err = EvaluateStream("sample.yaml", strings.NewReader(s.document), node, printer)
+				if err != nil {
+					t.Error(err)
+				}
 			} else {
 				err = EvaluateAllFileStreams(s.expression, []string{}, printer)
+				if err != nil {
+					t.Error(err)
+				}
 			}
 
-			w.WriteString(fmt.Sprintf("```yaml\n%v```\n", output.String()))
+			writeOrPanic(w, fmt.Sprintf("```yaml\n%v```\n", output.String()))
 
-			if err != nil {
-				t.Error(err)
-			}
 		}
 
 	}

pkg/yqlib/operatory_style.go

@@ -59,7 +59,7 @@ func GetStyleOperator(d *dataTreeNavigator, matchingNodes *list.List, pathNode *
 
 	for el := matchingNodes.Front(); el != nil; el = el.Next() {
 		candidate := el.Value.(*CandidateNode)
-		var style = ""
+		var style string
 		switch candidate.Node.Style {
 		case yaml.TaggedStyle:
 			style = "tagged"

pkg/yqlib/path_tokeniser.go

@@ -1,7 +1,6 @@
 package yqlib
 
 import (
-	"fmt"
 	"strconv"
 
 	lex "github.com/timtadh/lexmachine"
@@ -47,14 +46,14 @@ func (t *Token) toString() string {
 	} else if t.TokenType == CloseCollectObject {
 		return "}"
 	} else {
-		return fmt.Sprintf("NFI")
+		return "NFI"
 	}
 }
 
 func pathToken(wrapped bool) lex.Action {
 	return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
 		value := string(m.Bytes)
-		value = value[1:len(value)]
+		value = value[1:]
 		if wrapped {
 			value = unwrap(value)
 		}
@@ -73,7 +72,7 @@ func literalPathToken(value string) lex.Action {
 func documentToken() lex.Action {
 	return func(s *lex.Scanner, m *machines.Match) (interface{}, error) {
 		var numberString = string(m.Bytes)
-		numberString = numberString[1:len(numberString)]
+		numberString = numberString[1:]
 		var number, errParsingInt = strconv.ParseInt(numberString, 10, 64) // nolint
 		if errParsingInt != nil {
 			return nil, errParsingInt

pkg/yqlib/path_tree.go

@@ -7,8 +7,8 @@ var myPathPostfixer = NewPathPostFixer()
 
 type PathTreeNode struct {
 	Operation *Operation
-	Lhs         *PathTreeNode
+	Lhs       *PathTreeNode
-	Rhs         *PathTreeNode
+	Rhs       *PathTreeNode
 }
 
 type PathTreeCreator interface {

pkg/yqlib/printer.go

@@ -77,7 +77,10 @@ func (p *resultsPrinter) PrintResults(matchingNodes *list.List) error {
 		mappedDoc := el.Value.(*CandidateNode)
 
 		if (!p.firstTimePrinting || (previousDocIndex != mappedDoc.Document)) && p.printDocSeparators {
-			p.writeString(bufferedWriter, "---\n")
+			if err := p.writeString(bufferedWriter, "---\n"); err != nil {
+				return err
+			}
+
 		}
 
 		if err := p.printNode(mappedDoc.Node, bufferedWriter); err != nil {

pkg/yqlib/utils.go

@@ -46,7 +46,10 @@ func EvaluateStream(filename string, reader io.Reader, node *PathTreeNode, print
 		if errorParsing != nil {
 			return errorParsing
 		}
-		printer.PrintResults(matches)
+		err := printer.PrintResults(matches)
+		if err != nil {
+			return err
+		}
 		currentIndex = currentIndex + 1
 	}
 }
@@ -61,9 +64,9 @@ func readDocuments(reader io.Reader, filename string) (*list.List, error) {
 		errorReading := decoder.Decode(&dataBucket)
 
 		if errorReading == io.EOF {
-			switch reader.(type) {
+			switch reader := reader.(type) {
 			case *os.File:
-				safelyCloseFile(reader.(*os.File))
+				safelyCloseFile(reader)
 			}
 			return inputList, nil
 		} else if errorReading != nil {
@@ -122,49 +125,49 @@ func EvaluateFileStreamsSequence(expression string, filenames []string, printer
 			return err
 		}
 
-		switch reader.(type) {
+		switch reader := reader.(type) {
 		case *os.File:
-			safelyCloseFile(reader.(*os.File))
+			safelyCloseFile(reader)
 		}
 	}
 	return nil
 }
 
-func safelyRenameFile(from string, to string) {
+// func safelyRenameFile(from string, to string) {
-	if renameError := os.Rename(from, to); renameError != nil {
+// 	if renameError := os.Rename(from, to); renameError != nil {
-		log.Debugf("Error renaming from %v to %v, attempting to copy contents", from, to)
+// 		log.Debugf("Error renaming from %v to %v, attempting to copy contents", from, to)
-		log.Debug(renameError.Error())
+// 		log.Debug(renameError.Error())
-		// can't do this rename when running in docker to a file targeted in a mounted volume,
+// 		// can't do this rename when running in docker to a file targeted in a mounted volume,
-		// so gracefully degrade to copying the entire contents.
+// 		// so gracefully degrade to copying the entire contents.
-		if copyError := copyFileContents(from, to); copyError != nil {
+// 		if copyError := copyFileContents(from, to); copyError != nil {
-			log.Errorf("Failed copying from %v to %v", from, to)
+// 			log.Errorf("Failed copying from %v to %v", from, to)
-			log.Error(copyError.Error())
+// 			log.Error(copyError.Error())
-		} else {
+// 		} else {
-			removeErr := os.Remove(from)
+// 			removeErr := os.Remove(from)
-			if removeErr != nil {
+// 			if removeErr != nil {
-				log.Errorf("failed removing original file: %s", from)
+// 				log.Errorf("failed removing original file: %s", from)
-			}
+// 			}
-		}
+// 		}
-	}
+// 	}
-}
+// }
 
-// thanks https://stackoverflow.com/questions/21060945/simple-way-to-copy-a-file-in-golang
+// // thanks https://stackoverflow.com/questions/21060945/simple-way-to-copy-a-file-in-golang
-func copyFileContents(src, dst string) (err error) {
+// func copyFileContents(src, dst string) (err error) {
-	in, err := os.Open(src) // nolint gosec
+// 	in, err := os.Open(src) // nolint gosec
-	if err != nil {
+// 	if err != nil {
-		return err
+// 		return err
-	}
+// 	}
-	defer safelyCloseFile(in)
+// 	defer safelyCloseFile(in)
-	out, err := os.Create(dst)
+// 	out, err := os.Create(dst)
-	if err != nil {
+// 	if err != nil {
-		return err
+// 		return err
-	}
+// 	}
-	defer safelyCloseFile(out)
+// 	defer safelyCloseFile(out)
-	if _, err = io.Copy(out, in); err != nil {
+// 	if _, err = io.Copy(out, in); err != nil {
-		return err
+// 		return err
-	}
+// 	}
-	return out.Sync()
+// 	return out.Sync()
-}
+// }
 
 func safelyFlush(writer *bufio.Writer) {
 	if err := writer.Flush(); err != nil {

scripts/acceptance.sh

@@ -3,7 +3,7 @@
 set -e
 
 # acceptance test
-X=$(./yq w ./examples/sample.yaml b.c 3 | ./yq r - b.c)
+X=$(./yq e '.b.c |= 3' ./examples/sample.yaml | ./yq e '.b.c' -)
 
 if [[ $X != 3 ]]; then
   echo "Failed acceptance test: expected 3 but was $X"