Fix nullability of sop commands

sop-java-picocli/src/test/java/sop/cli/picocli/SOPTest.java

@@ -13,7 +13,6 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
-import org.jetbrains.annotations.NotNull;
 import org.junit.jupiter.api.Test;
 import sop.SOP;
 import sop.exception.SOPGPException;
@@ -57,25 +56,21 @@ public class SOPTest {
     @Test
     public void UnsupportedSubcommandsTest() {
         SOP nullCommandSOP = new SOP() {
-            @NotNull
             @Override
             public ValidateUserId validateUserId() {
                 return null;
             }
 
-            @NotNull
             @Override
             public CertifyUserId certifyUserId() {
                 return null;
             }
 
-            @NotNull
             @Override
             public MergeCerts mergeCerts() {
                 return null;
             }
 
-            @NotNull
             @Override
             public UpdateKey updateKey() {
                 return null;

sop-java/src/main/kotlin/sop/SOP.kt

@@ -15,60 +15,60 @@ import sop.operation.*
 interface SOP : SOPV {
 
     /** Generate a secret key. */
-    fun generateKey(): GenerateKey
+    fun generateKey(): GenerateKey?
 
     /** Extract a certificate (public key) from a secret key. */
-    fun extractCert(): ExtractCert
+    fun extractCert(): ExtractCert?
 
     /**
      * Create detached signatures. If you want to sign a message inline, use [inlineSign] instead.
      */
-    fun sign(): DetachedSign = detachedSign()
+    fun sign(): DetachedSign? = detachedSign()
 
     /**
      * Create detached signatures. If you want to sign a message inline, use [inlineSign] instead.
      */
-    fun detachedSign(): DetachedSign
+    fun detachedSign(): DetachedSign?
 
     /**
      * Sign a message using inline signatures. If you need to create detached signatures, use
      * [detachedSign] instead.
      */
-    fun inlineSign(): InlineSign
+    fun inlineSign(): InlineSign?
 
     /** Detach signatures from an inline signed message. */
-    fun inlineDetach(): InlineDetach
+    fun inlineDetach(): InlineDetach?
 
     /** Encrypt a message. */
-    fun encrypt(): Encrypt
+    fun encrypt(): Encrypt?
 
     /** Decrypt a message. */
-    fun decrypt(): Decrypt
+    fun decrypt(): Decrypt?
 
     /** Convert binary OpenPGP data to ASCII. */
-    fun armor(): Armor
+    fun armor(): Armor?
 
     /** Converts ASCII armored OpenPGP data to binary. */
-    fun dearmor(): Dearmor
+    fun dearmor(): Dearmor?
 
     /** List supported [Profiles][Profile] of a subcommand. */
-    fun listProfiles(): ListProfiles
+    fun listProfiles(): ListProfiles?
 
     /** Revoke one or more secret keys. */
-    fun revokeKey(): RevokeKey
+    fun revokeKey(): RevokeKey?
 
     /** Update a key's password. */
-    fun changeKeyPassword(): ChangeKeyPassword
+    fun changeKeyPassword(): ChangeKeyPassword?
 
     /** Keep a secret key up-to-date. */
-    fun updateKey(): UpdateKey
+    fun updateKey(): UpdateKey?
 
     /** Merge OpenPGP certificates. */
-    fun mergeCerts(): MergeCerts
+    fun mergeCerts(): MergeCerts?
 
     /** Certify OpenPGP Certificate User-IDs. */
-    fun certifyUserId(): CertifyUserId
+    fun certifyUserId(): CertifyUserId?
 
     /** Validate a UserID in an OpenPGP certificate. */
-    fun validateUserId(): ValidateUserId
+    fun validateUserId(): ValidateUserId?
 }

sop-java/src/main/kotlin/sop/SOPV.kt

@@ -12,23 +12,23 @@ import sop.operation.Version
 interface SOPV {
 
     /** Get information about the implementations name and version. */
-    fun version(): Version
+    fun version(): Version?
 
     /**
      * Verify detached signatures. If you need to verify an inline-signed message, use
      * [inlineVerify] instead.
      */
-    fun verify(): DetachedVerify = detachedVerify()
+    fun verify(): DetachedVerify? = detachedVerify()
 
     /**
      * Verify detached signatures. If you need to verify an inline-signed message, use
      * [inlineVerify] instead.
      */
-    fun detachedVerify(): DetachedVerify
+    fun detachedVerify(): DetachedVerify?
 
     /**
      * Verify signatures of an inline-signed message. If you need to verify detached signatures over
      * a message, use [detachedVerify] instead.
      */
-    fun inlineVerify(): InlineVerify
+    fun inlineVerify(): InlineVerify?
 }