Added expression argument to forcibly set expression if required

acceptance_tests/basic.sh

@@ -2,6 +2,7 @@
 
 setUp() {
   rm test*.yml || true
+  rm .xyz -f
 }
 
 testBasicEvalRoundTrip() {
@@ -16,6 +17,18 @@ testBasicPipeWithDot() {
   assertEquals "a: 123" "$X"
 }
 
+testBasicExpressionMatchesFileName() {
+  ./yq -n ".xyz = 123" > test.yml
+  touch .xyz
+  
+  X=$(./yq --expression '.xyz' test.yml)
+  assertEquals "123" "$X"
+
+  X=$(./yq ea --expression '.xyz' test.yml)
+  assertEquals "123" "$X"
+
+}
+
 testBasicGitHubAction() {
   ./yq -n ".a = 123" > test.yml
   X=$(cat /dev/null | ./yq test.yml)

cmd/constant.go

@@ -28,3 +28,5 @@ var frontMatter = ""
 var splitFileExp = ""
 
 var completedSuccessfully = false
+
+var forceExpression = ""

cmd/evaluate_all_command.go

@@ -126,27 +126,19 @@ func evaluateAll(cmd *cobra.Command, args []string) (cmdError error) {
 
 	allAtOnceEvaluator := yqlib.NewAllAtOnceEvaluator()
 
-	args = processArgs(pipingStdIn, args)
+	expression, args := processArgs(pipingStdIn, args)
 	yqlib.GetLogger().Debugf("processed args: %v", args)
 
 	switch len(args) {
 	case 0:
-		cmd.Println(cmd.UsageString())
-		return nil
-	case 1:
 		if nullInput {
-			err = yqlib.NewStreamEvaluator().EvaluateNew(processExpression(args[0]), printer, "")
+			err = yqlib.NewStreamEvaluator().EvaluateNew(processExpression(expression), printer, "")
 		} else {
-			err = allAtOnceEvaluator.EvaluateFiles(processExpression(""), []string{args[0]}, printer, leadingContentPreProcessing, decoder)
+			cmd.Println(cmd.UsageString())
+			return nil
 		}
 	default:
-		// the first argument is either an expression - or a file.
+		err = allAtOnceEvaluator.EvaluateFiles(processExpression(expression), args, printer, leadingContentPreProcessing, decoder)
-		if args[0] == "-" || maybeFile(args[0]) {
-			err = allAtOnceEvaluator.EvaluateFiles(processExpression(""), args, printer, leadingContentPreProcessing, decoder)
-		} else {
-			// first argument is an expression, the rest are files.
-			err = allAtOnceEvaluator.EvaluateFiles(processExpression(args[0]), args[1:], printer, leadingContentPreProcessing, decoder)
-		}
 	}
 
 	completedSuccessfully = err == nil

cmd/evalute_sequence_command.go

@@ -143,29 +143,18 @@ func evaluateSequence(cmd *cobra.Command, args []string) (cmdError error) {
 		}
 		defer frontMatterHandler.CleanUp()
 	}
-	args = processArgs(pipingStdIn, args)
+	expression, args := processArgs(pipingStdIn, args)
-	yqlib.GetLogger().Debugf("processed args: %v", args)
 
 	switch len(args) {
 	case 0:
-		cmd.Println(cmd.UsageString())
-		return nil
-	case 1:
 		if nullInput {
-			err = streamEvaluator.EvaluateNew(processExpression(args[0]), printer, "")
+			err = streamEvaluator.EvaluateNew(processExpression(expression), printer, "")
 		} else {
-			err = streamEvaluator.EvaluateFiles(processExpression(""), []string{args[0]}, printer, leadingContentPreProcessing, decoder)
+			cmd.Println(cmd.UsageString())
+			return nil
 		}
 	default:
-		// the first argument is either an expression - or a file.
+		err = streamEvaluator.EvaluateFiles(processExpression(expression), args, printer, leadingContentPreProcessing, decoder)
-		if args[0] == "-" || maybeFile(args[0]) {
-			// its a file, there is no expression given
-			err = streamEvaluator.EvaluateFiles(processExpression(""), args, printer, leadingContentPreProcessing, decoder)
-		} else {
-			// first argument is an expression, the rest are files.
-			err = streamEvaluator.EvaluateFiles(processExpression(args[0]), args[1:], printer, leadingContentPreProcessing, decoder)
-		}
-
 	}
 	completedSuccessfully = err == nil
 

cmd/root.go

@@ -81,6 +81,7 @@ yq -i '.stuff = "foo"' myfile.yml # update myfile.yml inplace
 	rootCmd.PersistentFlags().BoolVarP(&forceColor, "colors", "C", false, "force print with colors")
 	rootCmd.PersistentFlags().BoolVarP(&forceNoColor, "no-colors", "M", false, "force print with no colors")
 	rootCmd.PersistentFlags().StringVarP(&frontMatter, "front-matter", "f", "", "(extract|process) first input as yaml front-matter. Extract will pull out the yaml content, process will run the expression against the yaml content, leaving the remaining data intact")
+	rootCmd.PersistentFlags().StringVarP(&forceExpression, "expression", "", "", "forcibly set the expression argument. Useful when yq argument detection thinks your expression is a file.")
 	rootCmd.PersistentFlags().BoolVarP(&leadingContentPreProcessing, "header-preprocess", "", true, "Slurp any header comments and separators before processing expression.")
 
 	rootCmd.PersistentFlags().StringVarP(&splitFileExp, "split-exp", "s", "", "print each result (or doc) into a file named (exp). [exp] argument must return a string. You can use $index in the expression as the result counter.")

cmd/utils.go

@@ -113,7 +113,7 @@ func maybeFile(str string) bool {
 	return result
 }
 
-func processArgs(pipingStdin bool, args []string) []string {
+func processStdInArgs(pipingStdin bool, args []string) []string {
 	if !pipingStdin {
 		return args
 	}
@@ -129,3 +129,15 @@ func processArgs(pipingStdin bool, args []string) []string {
 	// lets add one to the end
 	return append(args, "-")
 }
+
+func processArgs(pipingStdin bool, originalArgs []string) (string, []string) {
+	args := processStdInArgs(pipingStdin, originalArgs)
+	yqlib.GetLogger().Debugf("processed args: %v", args)
+	expression := forceExpression
+	if expression == "" && len(args) > 0 && args[0] != "-" && !maybeFile(args[0]) {
+		yqlib.GetLogger().Debug("assuming expression is '%v'", args[0])
+		expression = args[0]
+		args = args[1:]
+	}
+	return expression, args
+}