Expose public/ API as submodule (#23345)

* model -> public/model

* plugin -> public/plugin

* public/model/utils -> public/utils

* platform/shared/mlog -> public/shared/mlog

* platform/shared/i18n -> public/shared/i18n

* platform/shared/markdown -> public/shared/markdown

* platform/services/timezones -> public/shared/timezones

* channels/einterfaces -> einterfaces

* expose public/ submodule

* go mod tidy

* .github: cache-dependency-path, setup-go-work

* modules-tidy for public/ too

* remove old gomodtidy

server/public/utils/json.go

@@ -0,0 +1,56 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package utils
+
+import (
+	"bytes"
+	"encoding/json"
+
+	"github.com/pkg/errors"
+)
+
+type HumanizedJSONError struct {
+	Err       error
+	Line      int
+	Character int
+}
+
+func (e *HumanizedJSONError) Error() string {
+	return e.Err.Error()
+}
+
+// HumanizeJSONError extracts error offsets and annotates the error with useful context
+func HumanizeJSONError(err error, data []byte) error {
+	if syntaxError, ok := err.(*json.SyntaxError); ok {
+		return NewHumanizedJSONError(syntaxError, data, syntaxError.Offset)
+	} else if unmarshalError, ok := err.(*json.UnmarshalTypeError); ok {
+		return NewHumanizedJSONError(unmarshalError, data, unmarshalError.Offset)
+	} else {
+		return err
+	}
+}
+
+func NewHumanizedJSONError(err error, data []byte, offset int64) *HumanizedJSONError {
+	if err == nil {
+		return nil
+	}
+
+	if offset < 0 || offset > int64(len(data)) {
+		return &HumanizedJSONError{
+			Err: errors.Wrapf(err, "invalid offset %d", offset),
+		}
+	}
+
+	lineSep := []byte{'\n'}
+
+	line := bytes.Count(data[:offset], lineSep) + 1
+	lastLineOffset := bytes.LastIndex(data[:offset], lineSep)
+	character := int(offset) - (lastLineOffset + 1) + 1
+
+	return &HumanizedJSONError{
+		Line:      line,
+		Character: character,
+		Err:       errors.Wrapf(err, "parsing error at line %d, character %d", line, character),
+	}
+}