From 799fafafe9dec61c7abbd8f4bbb3aea309c7b1b5 Mon Sep 17 00:00:00 2001
From: Randall Winkhart <idgr@tutanota.com>
Date: Sun, 1 Jun 2025 13:45:32 -0400
Subject: [PATCH] Return errors, rather than printing them; move PrintError()
 to front package

---
 back/cmd.go      |  7 ++++---
 back/files.go    | 21 +++++++++++----------
 back/general.go  | 18 ------------------
 front/general.go | 21 +++++++++++++++++++++
 4 files changed, 36 insertions(+), 31 deletions(-)
 create mode 100644 front/general.go

diff --git a/back/cmd.go b/back/cmd.go
index e90f33c..cb15c49 100644
--- a/back/cmd.go
+++ b/back/cmd.go
@@ -2,24 +2,25 @@ package back
 
 import (
 	"bufio"
+	"errors"
 	"io"
 	"os"
 	"os/exec"
 )
 
 // WriteToStdin is a utility function that writes a string to a command's stdin.
-func WriteToStdin(cmd *exec.Cmd, input string) {
+func WriteToStdin(cmd *exec.Cmd, input string) error {
 	stdin, err := cmd.StdinPipe()
 	if err != nil {
-		PrintError("Failed to access stdin for system command: "+err.Error(), ErrorOther, true)
+		return errors.New("unable to access stdin for system command: " + err.Error())
 	}
-
 	go func() {
 		defer func(stdin io.WriteCloser) {
 			_ = stdin.Close() // error ignored; if stdin could be accessed, it can probably be closed
 		}(stdin)
 		_, _ = io.WriteString(stdin, input)
 	}()
+	return nil
 }
 
 // ReadFromStdin is a utility function that reads a string from stdin.
diff --git a/back/files.go b/back/files.go
index e6ff9a2..3bf32a3 100644
--- a/back/files.go
+++ b/back/files.go
@@ -1,6 +1,7 @@
 package back
 
 import (
+	"errors"
 	"os"
 	"strings"
 )
@@ -8,34 +9,34 @@ import (
 // TargetIsFile checks if the targetLocation is a file, directory, or is inaccessible.
 // Requires: failCondition (0 = fail on inaccessible, 1 = fail on inaccessible&file, 2 = fail on inaccessible&directory).
 // Returns: isFile, isAccessible.
-func TargetIsFile(targetLocation string, errorOnFail bool, failCondition uint8) (bool, bool) {
+func TargetIsFile(targetLocation string, errorOnFail bool, failCondition uint8) (bool, bool, error) {
 	targetInfo, err := os.Stat(targetLocation)
 	if err != nil {
 		if errorOnFail {
-			PrintError("Failed to access \""+targetLocation+"\" - Ensure it exists and has the correct permissions", ErrorTargetNotFound, true)
+			return false, false, errors.New("unable to access \"" + targetLocation + "\": " + err.Error())
 		}
-		return false, false
+		return false, false, nil
 	}
 	if targetInfo.IsDir() {
 		if errorOnFail && failCondition == 2 {
-			PrintError("\""+targetLocation+"\" is a directory", ErrorTargetWrongType, true)
+			return false, true, errors.New("\"" + targetLocation + "\" is a directory")
 		}
-		return false, true
+		return false, true, nil
 	} else {
 		if errorOnFail && failCondition == 1 {
-			PrintError("\""+targetLocation+"\" is a file", ErrorTargetWrongType, true)
+			return true, true, errors.New("\"" + targetLocation + "\" is a file")
 		}
-		return true, true
+		return true, true, nil
 	}
 }
 
 // CreateTempFile creates a temporary file and returns a pointer to it.
-func CreateTempFile() *os.File {
+func CreateTempFile() (*os.File, error) {
 	tempFile, err := os.CreateTemp("", "*.markdown")
 	if err != nil {
-		PrintError("Failed to create temporary file: "+err.Error(), ErrorWrite, true)
+		return nil, errors.New("unable to create temporary file: " + err.Error())
 	}
-	return tempFile
+	return tempFile, nil
 }
 
 // ExpandPathWithHome, given a path (as a string) containing "~", returns the path with "~" expanded to the user's home directory.
diff --git a/back/general.go b/back/general.go
index d4bb6ba..08d5a3f 100644
--- a/back/general.go
+++ b/back/general.go
@@ -1,10 +1,5 @@
 package back
 
-import (
-	"fmt"
-	"os"
-)
-
 // RemoveTrailingEmptyStrings removes empty strings from the end of a slice.
 func RemoveTrailingEmptyStrings(slice []string) []string {
 	for i := len(slice) - 1; i >= 0; i-- {
@@ -14,16 +9,3 @@ func RemoveTrailingEmptyStrings(slice []string) []string {
 	}
 	return nil
 }
-
-// PrintError prints an error message in the standard libmutton format and exits with the specified exit code.
-// Requires: message (the error message to print),
-// exitCode (the exit code to use),
-// forceHardExit (if true, exit immediately; if false, allow soft exit for interactive clients).
-func PrintError(message string, exitCode int, forceHardExit bool) {
-	fmt.Println(AnsiError + message + AnsiReset)
-	if forceHardExit {
-		os.Exit(exitCode)
-	} else {
-		Exit(exitCode)
-	}
-}
diff --git a/front/general.go b/front/general.go
new file mode 100644
index 0000000..4345796
--- /dev/null
+++ b/front/general.go
@@ -0,0 +1,21 @@
+package front
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/rwinkhart/go-boilerplate/back"
+)
+
+// PrintError prints an error message in the MUTN format and exits with the specified exit code.
+// Requires: message (the error message to print),
+// exitCode (the exit code to use),
+// forceHardExit (if true, exit immediately; if false, allow soft exit for interactive clients).
+func PrintError(message string, exitCode int, forceHardExit bool) {
+	fmt.Println(back.AnsiError + message + back.AnsiReset)
+	if forceHardExit {
+		os.Exit(exitCode)
+	} else {
+		back.Exit(exitCode)
+	}
+}