Automatically add "-" when piping and its missing

acceptance_tests/basic.sh

@@ -16,14 +16,31 @@ testBasicPipeWithDot() {
   assertEquals "a: 123" "$X"
 }
 
-testBasicAllFiles() {
+testBasicGitHubAction() {
   ./yq -n ".a = 123" > test.yml
-  ./yq -n ".a = 124" > test2.yml
+  X=$(cat /dev/null | ./yq test.yml)
-  X=$(./yq test.yml test2.yml)
+  assertEquals "a: 123" "$X"
-  Y=$(./yq e '.' test.yml test2.yml)
+
-  assertEquals "$Y" "$X"
+  X=$(cat /dev/null | ./yq e test.yml)
+  assertEquals "a: 123" "$X"
+
+  X=$(cat /dev/null | ./yq ea test.yml)
+  assertEquals "a: 123" "$X"
 }
 
+testBasicGitHubActionWithExpression() {
+  ./yq -n ".a = 123" > test.yml
+  X=$(cat /dev/null | ./yq '.a' test.yml)
+  assertEquals "123" "$X"
+
+  X=$(cat /dev/null | ./yq e '.a' test.yml)
+  assertEquals "123" "$X"
+
+  X=$(cat /dev/null | ./yq ea '.a' test.yml)
+  assertEquals "123" "$X"
+}
+
+
 testBasicEvalAllAllFiles() {
   ./yq -n ".a = 123" > test.yml
   ./yq -n ".a = 124" > test2.yml
@@ -32,6 +49,38 @@ testBasicEvalAllAllFiles() {
   assertEquals "$Y" "$X"
 }
 
+testBasicCatWithFilesNoDash() {
+  ./yq -n ".a = 123" > test.yml
+  ./yq -n ".a = 124" > test2.yml
+  X=$(cat test.yml | ./yq test2.yml)
+  Y=$(./yq e '.' test2.yml test.yml)
+  assertEquals "$Y" "$X"
+}
+
+testBasicEvalAllCatWithFilesNoDash() {
+  ./yq -n ".a = 123" > test.yml
+  ./yq -n ".a = 124" > test2.yml
+  X=$(cat test.yml | ./yq ea test2.yml)
+  Y=$(./yq e '.' test2.yml test.yml)
+  assertEquals "$Y" "$X"
+}
+
+testBasicCatWithFilesNoDashWithExp() {
+  ./yq -n ".a = 123" > test.yml
+  ./yq -n ".a = 124" > test2.yml
+  X=$(cat test.yml | ./yq '.a' test2.yml)
+  Y=$(./yq e '.a' test2.yml test.yml)
+  assertEquals "$Y" "$X"
+}
+
+testBasicEvalAllCatWithFilesNoDashWithExp() {
+  ./yq -n ".a = 123" > test.yml
+  ./yq -n ".a = 124" > test2.yml
+  X=$(cat test.yml | ./yq ea '.a' test2.yml)
+  Y=$(./yq e '.a' test2.yml test.yml)
+  assertEquals "$Y" "$X"
+}
+
 
 testBasicStdInWithFiles() {
   ./yq -n ".a = 123" > test.yml

cmd/evaluate_all_command.go

@@ -125,21 +125,17 @@ func evaluateAll(cmd *cobra.Command, args []string) (cmdError error) {
 	}
 
 	allAtOnceEvaluator := yqlib.NewAllAtOnceEvaluator()
+
+	args = processArgs(pipingStdIn, args)
+	yqlib.GetLogger().Debugf("processed args: %v", args)
+
 	switch len(args) {
 	case 0:
-		if pipingStdIn {
-			err = allAtOnceEvaluator.EvaluateFiles(processExpression(""), []string{"-"}, printer, leadingContentPreProcessing, decoder)
-		} else {
 		cmd.Println(cmd.UsageString())
 		return nil
-		}
 	case 1:
 		if nullInput {
 			err = yqlib.NewStreamEvaluator().EvaluateNew(processExpression(args[0]), printer, "")
-		} else if pipingStdIn && args[0] != "-" && !maybeFile(args[0]) {
-			// must have given a single expression and piping input from stdin
-			err = allAtOnceEvaluator.EvaluateFiles(processExpression(args[0]), []string{"-"}, printer, leadingContentPreProcessing, decoder)
-
 		} else {
 			err = allAtOnceEvaluator.EvaluateFiles(processExpression(""), []string{args[0]}, printer, leadingContentPreProcessing, decoder)
 		}

cmd/evalute_sequence_command.go

@@ -125,10 +125,10 @@ func evaluateSequence(cmd *cobra.Command, args []string) (cmdError error) {
 	if err != nil {
 		return err
 	}
-
 	streamEvaluator := yqlib.NewStreamEvaluator()
 
 	if frontMatter != "" {
+		yqlib.GetLogger().Debug("using front matter handler")
 		frontMatterHandler := yqlib.NewFrontMatterHandler(args[firstFileIndex])
 		err = frontMatterHandler.Split()
 		if err != nil {
@@ -143,21 +143,16 @@ func evaluateSequence(cmd *cobra.Command, args []string) (cmdError error) {
 		}
 		defer frontMatterHandler.CleanUp()
 	}
+	args = processArgs(pipingStdIn, args)
+	yqlib.GetLogger().Debugf("processed args: %v", args)
 
 	switch len(args) {
 	case 0:
-		if pipingStdIn {
-			err = streamEvaluator.EvaluateFiles(processExpression(""), []string{"-"}, printer, leadingContentPreProcessing, decoder)
-		} else {
 		cmd.Println(cmd.UsageString())
 		return nil
-		}
 	case 1:
 		if nullInput {
 			err = streamEvaluator.EvaluateNew(processExpression(args[0]), printer, "")
-		} else if pipingStdIn && args[0] != "-" && !maybeFile(args[0]) {
-			// must have given a single expression and piping input from stdin
-			err = streamEvaluator.EvaluateFiles(processExpression(args[0]), []string{"-"}, printer, leadingContentPreProcessing, decoder)
 		} else {
 			err = streamEvaluator.EvaluateFiles(processExpression(""), []string{args[0]}, printer, leadingContentPreProcessing, decoder)
 		}

cmd/utils.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/mikefarah/yq/v4/pkg/yqlib"
 	"github.com/spf13/cobra"
+	"gopkg.in/op/go-logging.v1"
 )
 
 func initCommand(cmd *cobra.Command, args []string) (firstFileIndex int, err error) {
@@ -98,6 +99,33 @@ func configureEncoder(format yqlib.PrinterOutputFormat) yqlib.Encoder {
 // without this - yq detects there is stdin (thanks githubactions),
 // then tries to parse the filename as an expression
 func maybeFile(str string) bool {
+	yqlib.GetLogger().Debugf("checking '%v' is a file", str)
 	stat, err := os.Stat(str) // #nosec
-	return err == nil && !stat.IsDir()
+	result := err == nil && !stat.IsDir()
+	if yqlib.GetLogger().IsEnabledFor(logging.DEBUG) {
+		if err != nil {
+			yqlib.GetLogger().Debugf("error: %v", err)
+		} else {
+			yqlib.GetLogger().Debugf("error: %v, dir: %v", err, stat.IsDir())
+		}
+		yqlib.GetLogger().Debugf("result: %v", result)
+	}
+	return result
+}
+
+func processArgs(pipingStdin bool, args []string) []string {
+	if !pipingStdin {
+		return args
+	}
+
+	for _, arg := range args {
+		if arg == "-" {
+			return args
+		}
+	}
+	yqlib.GetLogger().Debugf("missing '-', adding it to the end")
+
+	// we're piping from stdin, but there's no '-' arg
+	// lets add one to the end
+	return append(args, "-")
 }

pkg/yqlib/operators_test.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"sort"
 	"strings"
 	"testing"
 
@@ -237,7 +238,14 @@ func documentInput(w *bufio.Writer, s expressionScenario) (string, string) {
 
 	envCommand := ""
 
-	for name, value := range s.environmentVariables {
+	envKeys := make([]string, 0, len(s.environmentVariables))
+	for k := range s.environmentVariables {
+		envKeys = append(envKeys, k)
+	}
+	sort.Strings(envKeys)
+
+	for _, name := range envKeys {
+		value := s.environmentVariables[name]
 		if envCommand == "" {
 			envCommand = fmt.Sprintf("%v=\"%v\" ", name, value)
 		} else {