Merge 1fc030afe4 into 6c06c459da

Revised the documentation for greater clarity: swapped the listed items for explicit and implicit SSL/TLS support, and detailed the supported SMTP authentication mechanisms in an itemized format. This ensures users understand all available options and configurations more clearly.

.github/FUNDING.yml

@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2022 Winni Neessen <winni@neessen.dev>
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT
 
 github: wneessen
 ko_fi: winni

.github/ISSUE_TEMPLATE/bug_report.yml

@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2022 Winni Neessen <winni@neessen.dev>
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT
 
 name: Bug Report
 description: Create a report to help us improve

.github/ISSUE_TEMPLATE/config.yml

@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2022 Winni Neessen <winni@neessen.dev>
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT
 
 blank_issues_enabled: false
 contact_links:

.github/ISSUE_TEMPLATE/feature_request.yml

@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2022 Winni Neessen <winni@neessen.dev>
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT
 
 name: Feature request
 description: Suggest an idea for this project

.github/dependabot.yml

@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT
 
 version: 2
 updates:

.github/workflows/codeql-analysis.yml

@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2022 Winni Neessen <winni@neessen.dev>
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT
 
 # For most projects, this workflow file will not need changing; you simply need
 # to commit it to your repository.
@@ -54,7 +54,7 @@ jobs:
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@662472033e021d55d94146f66f6058822b0b39fd # v3.27.0
+      uses: github/codeql-action/init@4f3212b61783c3c68e8309a0f18a699764811cda # v3.27.1
       with:
         languages: ${{ matrix.language }}
         # If you wish to specify custom queries, you can do so here or in a config file.
@@ -65,7 +65,7 @@ jobs:
     # Autobuild attempts to build any compiled languages  (C/C++, C#, or Java).
     # If this step fails, then you should remove it and run the build manually (see below)
     - name: Autobuild
-      uses: github/codeql-action/autobuild@662472033e021d55d94146f66f6058822b0b39fd # v3.27.0
+      uses: github/codeql-action/autobuild@4f3212b61783c3c68e8309a0f18a699764811cda # v3.27.1
 
     # ℹ️ Command-line programs to run using the OS shell.
     # 📚 https://git.io/JvXDl
@@ -79,4 +79,4 @@ jobs:
     #   make release
 
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@662472033e021d55d94146f66f6058822b0b39fd # v3.27.0
+      uses: github/codeql-action/analyze@4f3212b61783c3c68e8309a0f18a699764811cda # v3.27.1

.github/workflows/scorecards.yml

@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT
 
 # This workflow uses actions that are not certified by GitHub. They are provided
 # by a third-party and are governed by separate terms of service, privacy
@@ -75,6 +75,6 @@ jobs:
 
       # Upload the results to GitHub's code scanning dashboard.
       - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@662472033e021d55d94146f66f6058822b0b39fd # v3.27.0
+        uses: github/codeql-action/upload-sarif@4f3212b61783c3c68e8309a0f18a699764811cda # v3.27.1
         with:
           sarif_file: results.sarif

.gitignore

@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2022 Winni Neessen <winni@neessen.dev>
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT
 
 # Binaries for programs and plugins
 *.exe

CODE_OF_CONDUCT.md

@@ -1,7 +1,7 @@
 <!--
 SPDX-FileCopyrightText: 2022 Winni Neessen <winni@neessen.dev>
 
-SPDX-License-Identifier: CC0-1.0
+SPDX-License-Identifier: MIT
 -->
 
 # Contributor Covenant Code of Conduct

CONTRIBUTING.md

@@ -1,7 +1,7 @@
 <!--
 SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
 
-SPDX-License-Identifier: CC0-1.0
+SPDX-License-Identifier: MIT
 -->
 
 # How to contribute

LICENSES/CC0-1.0.txt

@@ -1,121 +0,0 @@
-Creative Commons Legal Code
-
-CC0 1.0 Universal
-
-    CREATIVE COMMONS CORPORATION IS NOT A LAW FIRM AND DOES NOT PROVIDE
-    LEGAL SERVICES. DISTRIBUTION OF THIS DOCUMENT DOES NOT CREATE AN
-    ATTORNEY-CLIENT RELATIONSHIP. CREATIVE COMMONS PROVIDES THIS
-    INFORMATION ON AN "AS-IS" BASIS. CREATIVE COMMONS MAKES NO WARRANTIES
-    REGARDING THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS
-    PROVIDED HEREUNDER, AND DISCLAIMS LIABILITY FOR DAMAGES RESULTING FROM
-    THE USE OF THIS DOCUMENT OR THE INFORMATION OR WORKS PROVIDED
-    HEREUNDER.
-
-Statement of Purpose
-
-The laws of most jurisdictions throughout the world automatically confer
-exclusive Copyright and Related Rights (defined below) upon the creator
-and subsequent owner(s) (each and all, an "owner") of an original work of
-authorship and/or a database (each, a "Work").
-
-Certain owners wish to permanently relinquish those rights to a Work for
-the purpose of contributing to a commons of creative, cultural and
-scientific works ("Commons") that the public can reliably and without fear
-of later claims of infringement build upon, modify, incorporate in other
-works, reuse and redistribute as freely as possible in any form whatsoever
-and for any purposes, including without limitation commercial purposes.
-These owners may contribute to the Commons to promote the ideal of a free
-culture and the further production of creative, cultural and scientific
-works, or to gain reputation or greater distribution for their Work in
-part through the use and efforts of others.
-
-For these and/or other purposes and motivations, and without any
-expectation of additional consideration or compensation, the person
-associating CC0 with a Work (the "Affirmer"), to the extent that he or she
-is an owner of Copyright and Related Rights in the Work, voluntarily
-elects to apply CC0 to the Work and publicly distribute the Work under its
-terms, with knowledge of his or her Copyright and Related Rights in the
-Work and the meaning and intended legal effect of CC0 on those rights.
-
-1. Copyright and Related Rights. A Work made available under CC0 may be
-protected by copyright and related or neighboring rights ("Copyright and
-Related Rights"). Copyright and Related Rights include, but are not
-limited to, the following:
-
-  i. the right to reproduce, adapt, distribute, perform, display,
-     communicate, and translate a Work;
- ii. moral rights retained by the original author(s) and/or performer(s);
-iii. publicity and privacy rights pertaining to a person's image or
-     likeness depicted in a Work;
- iv. rights protecting against unfair competition in regards to a Work,
-     subject to the limitations in paragraph 4(a), below;
-  v. rights protecting the extraction, dissemination, use and reuse of data
-     in a Work;
- vi. database rights (such as those arising under Directive 96/9/EC of the
-     European Parliament and of the Council of 11 March 1996 on the legal
-     protection of databases, and under any national implementation
-     thereof, including any amended or successor version of such
-     directive); and
-vii. other similar, equivalent or corresponding rights throughout the
-     world based on applicable law or treaty, and any national
-     implementations thereof.
-
-2. Waiver. To the greatest extent permitted by, but not in contravention
-of, applicable law, Affirmer hereby overtly, fully, permanently,
-irrevocably and unconditionally waives, abandons, and surrenders all of
-Affirmer's Copyright and Related Rights and associated claims and causes
-of action, whether now known or unknown (including existing as well as
-future claims and causes of action), in the Work (i) in all territories
-worldwide, (ii) for the maximum duration provided by applicable law or
-treaty (including future time extensions), (iii) in any current or future
-medium and for any number of copies, and (iv) for any purpose whatsoever,
-including without limitation commercial, advertising or promotional
-purposes (the "Waiver"). Affirmer makes the Waiver for the benefit of each
-member of the public at large and to the detriment of Affirmer's heirs and
-successors, fully intending that such Waiver shall not be subject to
-revocation, rescission, cancellation, termination, or any other legal or
-equitable action to disrupt the quiet enjoyment of the Work by the public
-as contemplated by Affirmer's express Statement of Purpose.
-
-3. Public License Fallback. Should any part of the Waiver for any reason
-be judged legally invalid or ineffective under applicable law, then the
-Waiver shall be preserved to the maximum extent permitted taking into
-account Affirmer's express Statement of Purpose. In addition, to the
-extent the Waiver is so judged Affirmer hereby grants to each affected
-person a royalty-free, non transferable, non sublicensable, non exclusive,
-irrevocable and unconditional license to exercise Affirmer's Copyright and
-Related Rights in the Work (i) in all territories worldwide, (ii) for the
-maximum duration provided by applicable law or treaty (including future
-time extensions), (iii) in any current or future medium and for any number
-of copies, and (iv) for any purpose whatsoever, including without
-limitation commercial, advertising or promotional purposes (the
-"License"). The License shall be deemed effective as of the date CC0 was
-applied by Affirmer to the Work. Should any part of the License for any
-reason be judged legally invalid or ineffective under applicable law, such
-partial invalidity or ineffectiveness shall not invalidate the remainder
-of the License, and in such case Affirmer hereby affirms that he or she
-will not (i) exercise any of his or her remaining Copyright and Related
-Rights in the Work or (ii) assert any associated claims and causes of
-action with respect to the Work, in either case contrary to Affirmer's
-express Statement of Purpose.
-
-4. Limitations and Disclaimers.
-
- a. No trademark or patent rights held by Affirmer are waived, abandoned,
-    surrendered, licensed or otherwise affected by this document.
- b. Affirmer offers the Work as-is and makes no representations or
-    warranties of any kind concerning the Work, express, implied,
-    statutory or otherwise, including without limitation warranties of
-    title, merchantability, fitness for a particular purpose, non
-    infringement, or the absence of latent or other defects, accuracy, or
-    the present or absence of errors, whether or not discoverable, all to
-    the greatest extent permissible under applicable law.
- c. Affirmer disclaims responsibility for clearing rights of other persons
-    that may apply to the Work or any use thereof, including without
-    limitation any person's Copyright and Related Rights in the Work.
-    Further, Affirmer disclaims responsibility for obtaining any necessary
-    consents, permissions or other rights required for any use of the
-    Work.
- d. Affirmer understands and acknowledges that Creative Commons is not a
-    party to this document and has no duty or obligation with respect to
-    this CC0 or use of the Work.

README.md

@@ -1,7 +1,7 @@
 <!--
 SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
 
-SPDX-License-Identifier: CC0-1.0
+SPDX-License-Identifier: MIT
 -->
 
 # go-mail - Easy to use, yet comprehensive library for sending mails with Go
@@ -39,10 +39,16 @@ Here are some highlights of go-mail's featureset:
 * [X] Very small dependency footprint (mainly Go Stdlib and Go extended packages)
 * [X] Modern, idiomatic Go
 * [X] Sane and secure defaults
-* [X] Explicit SSL/TLS support
-* [X] Implicit StartTLS support with different policies
+* [X] Implicit SSL/TLS support
+* [X] Explicit STARTTLS support with different policies
 * [X] Makes use of contexts for a better control flow and timeout/cancelation handling
-* [X] SMTP Auth support (LOGIN, PLAIN, CRAM-MD, XOAUTH2, SCRAM-SHA-1(-PLUS), SCRAM-SHA-256(-PLUS))
+* [X] SMTP Auth support
+  * [X] CRAM-MD5
+  * [X] LOGIN
+  * [X] PLAIN
+  * [X] SCRAM-SHA-1/SCRAM-SHA-1-PLUS
+  * [X] SCRAM-SHA-256/SCRAM-SHA-256-PLUS
+  * [X] XOAUTH2
 * [X] RFC5322 compliant mail address validation
 * [X] Support for common mail header field generation (Message-ID, Date, Bulk-Precedence, Priority, etc.)
 * [X] Concurrency-safe reusing the same SMTP connection to send multiple mails

SECURITY.md

@@ -1,7 +1,7 @@
 <!--
 SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
 
-SPDX-License-Identifier: CC0-1.0
+SPDX-License-Identifier: MIT
 -->
 
 # Security Policy

client_test.go

@@ -2803,7 +2803,7 @@ func TestClient_sendSingleMsg(t *testing.T) {
 			t.Errorf("expected ErrGetSender, got %s", sendErr.Reason)
 		}
 	})
-	t.Run("fail with no recepient addresses", func(t *testing.T) {
+	t.Run("fail with no recipient addresses", func(t *testing.T) {
 		ctx, cancel := context.WithCancel(context.Background())
 		defer cancel()
 		PortAdder.Add(1)

codecov.yml

@@ -1,19 +1,19 @@
 # SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT
 
 coverage:
   status:
     project:
       default:
-        target: 90%
+        target: 95%
         threshold: 2%
         base: auto 
         if_ci_failed: error
         only_pulls: false
     patch:
       default:
-        target: 90%
+        target: 95%
         base: auto
         if_ci_failed: error
         threshold: 2%

msg_test.go

@@ -126,8 +126,8 @@ var (
 		{`" "@domain.tld`, true},             // Still valid, since quoted
 		{`"<\"@\".!#%$@domain.tld"`, false},  // Quoting with illegal characters is not allowed
 		{`<\"@\\".!#%$@domain.tld`, false},   // Still a bunch of random illegal characters
-		{`hi"@"there@domain.tld`, false},     // Quotes must be dot-seperated
-		{`"<\"@\\".!.#%$@domain.tld`, false}, // Quote is escaped and dot-seperated which would be RFC822 compliant, but not RFC5322 compliant
+		{`hi"@"there@domain.tld`, false},     // Quotes must be dot-separated
+		{`"<\"@\\".!.#%$@domain.tld`, false}, // Quote is escaped and dot-separated which would be RFC822 compliant, but not RFC5322 compliant
 		{`hi\ there@domain.tld`, false},      // Spaces must be quoted
 		{"hello@tld", true},                  // TLD is enough
 		{`你好@域名.顶级域名`, true},                 // We speak RFC6532
@@ -4527,12 +4527,12 @@ func TestMsg_AttachFile(t *testing.T) {
 			t.Errorf("expected message body to be %s, got: %s", "This is a test attachment", got)
 		}
 	})
-	t.Run("AttachFile with non-existant file", func(t *testing.T) {
+	t.Run("AttachFile with non-existent file", func(t *testing.T) {
 		message := NewMsg()
 		if message == nil {
 			t.Fatal("message is nil")
 		}
-		message.AttachFile("testdata/non-existant-file.txt")
+		message.AttachFile("testdata/non-existent-file.txt")
 		attachments := message.GetAttachments()
 		if len(attachments) != 0 {
 			t.Fatalf("failed to retrieve attachments list")
@@ -4997,12 +4997,12 @@ func TestMsg_EmbedFile(t *testing.T) {
 			t.Errorf("expected message body to be %s, got: %s", "This is a test embed", got)
 		}
 	})
-	t.Run("EmbedFile with non-existant file", func(t *testing.T) {
+	t.Run("EmbedFile with non-existent file", func(t *testing.T) {
 		message := NewMsg()
 		if message == nil {
 			t.Fatal("message is nil")
 		}
-		message.EmbedFile("testdata/non-existant-file.txt")
+		message.EmbedFile("testdata/non-existent-file.txt")
 		embeds := message.GetEmbeds()
 		if len(embeds) != 0 {
 			t.Fatalf("failed to retrieve attachments list")

msgwriter_test.go

@@ -324,7 +324,7 @@ func TestMsgWriter_addFiles(t *testing.T) {
 			}
 		}
 		if !strings.Contains(buffer.String(), `Content-Disposition: attachment; filename="attachment.txt"`) {
-			t.Errorf("Content-Dispositon header not found for attachment. Mail: %s", buffer.String())
+			t.Errorf("Content-Disposition header not found for attachment. Mail: %s", buffer.String())
 		}
 		switch runtime.GOOS {
 		case "freebsd":
@@ -357,7 +357,7 @@ func TestMsgWriter_addFiles(t *testing.T) {
 			}
 		}
 		if !strings.Contains(buffer.String(), `Content-Disposition: attachment; filename="attachment"`) {
-			t.Errorf("Content-Dispositon header not found for attachment. Mail: %s", buffer.String())
+			t.Errorf("Content-Disposition header not found for attachment. Mail: %s", buffer.String())
 		}
 		if !strings.Contains(buffer.String(), `Content-Type: application/octet-stream; name="attachment"`) {
 			t.Errorf("Content-Type header not found for attachment. Mail: %s", buffer.String())
@@ -383,7 +383,7 @@ func TestMsgWriter_addFiles(t *testing.T) {
 			}
 		}
 		if !strings.Contains(buffer.String(), `Content-Disposition: attachment; filename="attachment.txt"`) {
-			t.Errorf("Content-Dispositon header not found for attachment. Mail: %s", buffer.String())
+			t.Errorf("Content-Disposition header not found for attachment. Mail: %s", buffer.String())
 		}
 		if !strings.Contains(buffer.String(), `Content-Type: application/octet-stream; name="attachment.txt"`) {
 			t.Errorf("Content-Type header not found for attachment. Mail: %s", buffer.String())
@@ -402,7 +402,7 @@ func TestMsgWriter_addFiles(t *testing.T) {
 			t.Errorf("attachment not found in mail message. Mail: %s", buffer.String())
 		}
 		if !strings.Contains(buffer.String(), `Content-Disposition: attachment; filename="attachment.txt"`) {
-			t.Errorf("Content-Dispositon header not found for attachment. Mail: %s", buffer.String())
+			t.Errorf("Content-Disposition header not found for attachment. Mail: %s", buffer.String())
 		}
 		switch runtime.GOOS {
 		case "freebsd":
@@ -438,7 +438,7 @@ func TestMsgWriter_addFiles(t *testing.T) {
 			}
 		}
 		if !strings.Contains(buffer.String(), `Content-Disposition: attachment; filename="attachment.txt"`) {
-			t.Errorf("Content-Dispositon header not found for attachment. Mail: %s", buffer.String())
+			t.Errorf("Content-Disposition header not found for attachment. Mail: %s", buffer.String())
 		}
 		switch runtime.GOOS {
 		case "freebsd":
@@ -478,7 +478,7 @@ func TestMsgWriter_addFiles(t *testing.T) {
 			}
 		}
 		if !strings.Contains(buffer.String(), `Content-Disposition: attachment; filename="attachment.txt"`) {
-			t.Errorf("Content-Dispositon header not found for attachment. Mail: %s", buffer.String())
+			t.Errorf("Content-Disposition header not found for attachment. Mail: %s", buffer.String())
 		}
 		switch runtime.GOOS {
 		case "freebsd":

senderror.go

@@ -133,6 +133,10 @@ func (e *SendError) Is(errType error) bool {
 	return false
 }
 
+func (e *SendError) Unwrap() []error {
+	return e.errlist
+}
+
 // IsTemp returns true if the delivery error is of a temporary nature and can be retried.
 //
 // This function checks whether the SendError indicates a temporary error, which suggests
@@ -224,3 +228,5 @@ func (r SendErrReason) String() string {
 func isTempError(err error) bool {
 	return err.Error()[0] == '4'
 }
+
+var _ interface{ Unwrap() []error } = &SendError{}

senderror_test.go

@@ -174,6 +174,12 @@ func TestSendError_MessageID(t *testing.T) {
 			t.Errorf("sendError expected empty message-id, got: %s", sendErr.MessageID())
 		}
 	})
+	t.Run("TestSendError_MessageID on nil error should return empty", func(t *testing.T) {
+		var sendErr *SendError
+		if sendErr.MessageID() != "" {
+			t.Error("expected empty message-id on nil-senderror")
+		}
+	})
 }
 
 func TestSendError_Msg(t *testing.T) {

smtp/auth_login.go

@@ -36,8 +36,8 @@ type loginAuth struct {
 // LoginAuth will only send the credentials if the connection is using TLS
 // or is connected to localhost. Otherwise authentication will fail with an
 // error, without sending the credentials.
-func LoginAuth(username, password, host string, allowUnEnc bool) Auth {
-	return &loginAuth{username, password, host, 0, allowUnEnc}
+func LoginAuth(username, password, host string, allowUnenc bool) Auth {
+	return &loginAuth{username, password, host, 0, allowUnenc}
 }
 
 // Start begins the SMTP authentication process by validating server's TLS status and hostname.

smtp/auth_plain.go

@@ -28,8 +28,8 @@ type plainAuth struct {
 // PlainAuth will only send the credentials if the connection is using TLS
 // or is connected to localhost. Otherwise authentication will fail with an
 // error, without sending the credentials.
-func PlainAuth(identity, username, password, host string, allowUnEnc bool) Auth {
-	return &plainAuth{identity, username, password, host, allowUnEnc}
+func PlainAuth(identity, username, password, host string, allowUnenc bool) Auth {
+	return &plainAuth{identity, username, password, host, allowUnenc}
 }
 
 func (a *plainAuth) Start(server *ServerInfo) (string, []byte, error) {

smtp/auth_scram.go

@@ -154,7 +154,7 @@ func (a *scramAuth) initialClientMessage() ([]byte, error) {
 		connState := a.tlsConnState
 		bindData := connState.TLSUnique
 
-		// crypto/tl: no tls-unique channel binding value for this tls connection, possibly due to missing
+		// crypto/tls: no tls-unique channel binding value for this tls connection, possibly due to missing
 		// extended master key support and/or resumed connection
 		// RFC9266:122 tls-unique not defined for tls 1.3 and later
 		if bindData == nil || connState.Version >= tls.VersionTLS13 {
@@ -308,10 +308,7 @@ func (a *scramAuth) normalizeUsername() (string, error) {
 func (a *scramAuth) normalizeString(s string) (string, error) {
 	s, err := precis.OpaqueString.String(s)
 	if err != nil {
-		return "", fmt.Errorf("failled to normalize string: %w", err)
-	}
-	if s == "" {
-		return "", errors.New("normalized string is empty")
+		return "", fmt.Errorf("failed to normalize string: %w", err)
 	}
 	return s, nil
 }

smtp/smtp.go

@@ -587,7 +587,9 @@ func (c *Client) SetLogger(l log.Logger) {
 	if l == nil {
 		return
 	}
+	c.mutex.Lock()
 	c.logger = l
+	c.mutex.Unlock()
 }
 
 // SetLogAuthData enables logging of authentication data in the Client.
@@ -620,6 +622,9 @@ func (c *Client) HasConnection() bool {
 func (c *Client) UpdateDeadline(timeout time.Duration) error {
 	c.mutex.Lock()
 	defer c.mutex.Unlock()
+	if c.conn == nil {
+		return errors.New("smtp: client has no connection")
+	}
 	if err := c.conn.SetDeadline(time.Now().Add(timeout)); err != nil {
 		return fmt.Errorf("smtp: failed to update deadline: %w", err)
 	}

smtp/smtp_121_test.go

@@ -0,0 +1,59 @@
+// SPDX-FileCopyrightText: Copyright 2010 The Go Authors. All rights reserved.
+// SPDX-FileCopyrightText: Copyright (c) 2022-2023 The go-mail Authors
+//
+// Original net/smtp code from the Go stdlib by the Go Authors.
+// Use of this source code is governed by a BSD-style
+// LICENSE file that can be found in this directory.
+//
+// go-mail specific modifications by the go-mail Authors.
+// Licensed under the MIT License.
+// See [PROJECT ROOT]/LICENSES directory for more information.
+//
+// SPDX-License-Identifier: BSD-3-Clause AND MIT
+
+//go:build go1.21
+// +build go1.21
+
+package smtp
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"testing"
+
+	"github.com/wneessen/go-mail/log"
+)
+
+func TestClient_SetDebugLog_JSON(t *testing.T) {
+	t.Run("set debug loggging to on should not override logger", func(t *testing.T) {
+		client := &Client{logger: log.NewJSON(os.Stderr, log.LevelDebug)}
+		client.SetDebugLog(true)
+		if !client.debug {
+			t.Fatalf("expected debug log to be true")
+		}
+		if client.logger == nil {
+			t.Fatalf("expected logger to be defined")
+		}
+		if !strings.EqualFold(fmt.Sprintf("%T", client.logger), "*log.JSONlog") {
+			t.Errorf("expected logger to be of type *log.JSONlog, got: %T", client.logger)
+		}
+	})
+}
+
+func TestClient_SetLogger_JSON(t *testing.T) {
+	t.Run("set logger to JSONlog logger", func(t *testing.T) {
+		client := &Client{}
+		client.SetLogger(log.NewJSON(os.Stderr, log.LevelDebug))
+		if !strings.EqualFold(fmt.Sprintf("%T", client.logger), "*log.JSONlog") {
+			t.Errorf("expected logger to be of type *log.JSONlog, got: %T", client.logger)
+		}
+	})
+	t.Run("nil logger should just return and not set/override", func(t *testing.T) {
+		client := &Client{logger: log.NewJSON(os.Stderr, log.LevelDebug)}
+		client.SetLogger(nil)
+		if !strings.EqualFold(fmt.Sprintf("%T", client.logger), "*log.JSONlog") {
+			t.Errorf("expected logger to be of type *log.JSONlog, got: %T", client.logger)
+		}
+	})
+}

sonar-project.properties

@@ -1,6 +1,6 @@
 # SPDX-FileCopyrightText: 2022-2023 The go-mail Authors
 #
-# SPDX-License-Identifier: CC0-1.0
+# SPDX-License-Identifier: MIT
 
 sonar.projectKey=go-mail
 sonar.go.coverage.reportPaths=cov.out