Introduce Block interface and replace AbstractBlock.

In order to allow Authority to know about user blocks,
we need a narrow interface to represent such blocks.

This deprecates some methods on AbstractBlocks in favor
of new methods on the Block interface that avoid binding to
the User class.

Bug: T271494
Change-Id: I7bb950533970984a014de0434518fbbefb695131

21 files changed, 296 insertions, 85 deletions

diff --git a/RELEASE-NOTES-1.37 b/RELEASE-NOTES-1.37
index e6630b2e4be3..862971539644 100644
--- a/RELEASE-NOTES-1.37
+++ b/RELEASE-NOTES-1.37
@@ -199,6 +199,9 @@ because of Phabricator reports.
 
 === Deprecations in 1.37 ===
 * JobQueue::getWiki, deprecated in 1.33, now emits deprecation warnings.
+* In AbstractBlock, the getTargetAndType() and getTarget() methods are
+  deprecated. Instead use getTargetName() and getTargetUserIdentity() together
+  with getType().
 * Deprecated passing UserIdentity to
   WatchlistManager::clearAllUserNotifications() and
   WatchlistManager::clearTitleUserNotifications(). Pass Authority instead.
diff --git a/includes/EditPage.php b/includes/EditPage.php
index e9adf4dc831e..e4a7ddb967b5 100644
--- a/includes/EditPage.php
+++ b/includes/EditPage.php
@@ -2746,7 +2746,7 @@ class EditPage implements IEditObject {
 					$out,
 					'block',
 					MediaWikiServices::getInstance()->getNamespaceInfo()->
-						getCanonicalName( NS_USER ) . ':' . $block->getTarget(),
+						getCanonicalName( NS_USER ) . ':' . $block->getTargetName(),
 					'',
 					[
 						'lim' => 1,
diff --git a/includes/api/ApiBlockInfoTrait.php b/includes/api/ApiBlockInfoTrait.php
index 7f9ac9f8766f..e0f8bddb9cef 100644
--- a/includes/api/ApiBlockInfoTrait.php
+++ b/includes/api/ApiBlockInfoTrait.php
@@ -18,7 +18,7 @@
  * @file
  */
 
-use MediaWiki\Block\AbstractBlock;
+use MediaWiki\Block\Block;
 use MediaWiki\Block\SystemBlock;
 
 /**
@@ -28,7 +28,7 @@ trait ApiBlockInfoTrait {
 
 	/**
 	 * Get basic info about a given block
-	 * @param AbstractBlock $block
+	 * @param Block $block
 	 * @param Language|null $language
 	 * @return array Array containing several keys:
 	 *  - blockid - ID of the block
@@ -41,17 +41,19 @@ trait ApiBlockInfoTrait {
 	 *  - systemblocktype - system block type, if any
 	 */
 	private function getBlockDetails(
-		AbstractBlock $block,
+		Block $block,
 		$language = null
 	) {
 		if ( $language === null ) {
 			$language = $this->getLanguage();
 		}
 
+		$blocker = $block->getBlocker();
+
 		$vals = [];
 		$vals['blockid'] = $block->getId();
-		$vals['blockedby'] = $block->getByName();
-		$vals['blockedbyid'] = $block->getBy();
+		$vals['blockedby'] = $blocker ? $blocker->getName() : '';
+		$vals['blockedbyid'] = $blocker ? $blocker->getId() : 0;
 		$vals['blockreason'] = $block->getReasonComment()
 			->message->inLanguage( $language )->plain();
 		$vals['blockedtimestamp'] = wfTimestamp( TS_ISO_8601, $block->getTimestamp() );
diff --git a/includes/block/AbstractBlock.php b/includes/block/AbstractBlock.php
index c56859b5f02c..49280ef4f168 100644
--- a/includes/block/AbstractBlock.php
+++ b/includes/block/AbstractBlock.php
@@ -34,7 +34,7 @@ use User;
  * @note Extensions should not subclass this, as MediaWiki currently does not support custom block types.
  * @since 1.34 Factored out from DatabaseBlock (previously Block).
  */
-abstract class AbstractBlock {
+abstract class AbstractBlock implements Block {
 	/** @var CommentStoreComment */
 	protected $reason;
 
@@ -80,14 +80,6 @@ abstract class AbstractBlock {
 	/** @var bool */
 	protected $isSitewide = true;
 
-	# TYPE constants
-	# Do not introduce negative constants without changing BlockUser command object.
-	public const TYPE_USER = 1;
-	public const TYPE_IP = 2;
-	public const TYPE_RANGE = 3;
-	public const TYPE_AUTO = 4;
-	public const TYPE_ID = 5;
-
 	/**
 	 * Create a new block with specified parameters on a user, IP or IP range.
 	 *
@@ -139,15 +131,6 @@ abstract class AbstractBlock {
 	}
 
 	/**
-	 * Get the information that identifies this block, such that a user could
-	 * look up everything that can be found about this block. May be an ID,
-	 * array of IDs, type, etc.
-	 *
-	 * @return mixed Identifying information
-	 */
-	abstract public function getIdentifier();
-
-	/**
 	 * Get the reason given for creating the block, as a string.
 	 *
 	 * Deprecated, since this gives the caller no control over the language
@@ -350,6 +333,9 @@ abstract class AbstractBlock {
 	 *
 	 * If the type is not null, it will be an AbstractBlock::TYPE_ constant.
 	 *
+	 * @deprecated since 1.37, use getTargetName() and getTargetUserIdentity()
+	 *             together with getType()
+	 *
 	 * @return array [ User|String|null, int|null ]
 	 * @todo FIXME: This should be an integral part of the block member variables
 	 */
@@ -358,9 +344,11 @@ abstract class AbstractBlock {
 	}
 
 	/**
-	 * Get the target for this particular block.  Note that for autoblocks,
+	 * Get the target for this particular block. Note that for autoblocks,
 	 * this returns the unredacted name; frontend functions need to call $block->getRedactedName()
 	 * in this situation.
+	 * @deprecated since 1.37, use getTargetName() and getTargetUserIdentity()
+	 *             together with getType()
 	 * @return User|string|null
 	 */
 	public function getTarget() {
@@ -368,6 +356,38 @@ abstract class AbstractBlock {
 	}
 
 	/**
+	 * @since 1.37
+	 * @return ?UserIdentity
+	 */
+	public function getTargetUserIdentity(): ?UserIdentity {
+		return $this->target instanceof UserIdentity ? $this->target : null;
+	}
+
+	/**
+	 * @since 1.37
+	 * @return string
+	 */
+	public function getTargetName(): string {
+		return $this->target instanceof UserIdentity
+			? $this->target->getName()
+			: (string)$this->target;
+	}
+
+	/**
+	 * @param UserIdentity|string $target
+	 *
+	 * @return bool
+	 * @since 1.37
+	 */
+	public function isBlocking( $target ): bool {
+		$targetName = $target instanceof UserIdentity
+			? $target->getName()
+			: (string)$target;
+
+		return $targetName === $this->getTargetName();
+	}
+
+	/**
 	 * Get the block expiry time
 	 *
 	 * @since 1.19
diff --git a/includes/block/Block.php b/includes/block/Block.php
new file mode 100644
index 000000000000..523a23d3166a
--- /dev/null
+++ b/includes/block/Block.php
@@ -0,0 +1,150 @@
+<?php
+
+/**
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+namespace MediaWiki\Block;
+
+use CommentStoreComment;
+use MediaWiki\User\UserIdentity;
+
+/**
+ * Represents a block that may prevent users from performing specific operations.
+ * The block may apply to a specific user, to a network address, network range,
+ * or some other aspect of a web request.
+ * The block may apply to the entire site, or may be limited to specific pages
+ * or namespaces.
+ *
+ * @since 1.37 Extracted from the AbstractBlock base class,
+ * which was in turn factored out of DatabaseBlock in 1.34.
+ */
+interface Block {
+
+	# TYPE constants
+	# Do not introduce negative constants without changing BlockUser command object.
+	public const TYPE_USER = 1;
+	public const TYPE_IP = 2;
+	public const TYPE_RANGE = 3;
+	public const TYPE_AUTO = 4;
+	public const TYPE_ID = 5;
+
+	/**
+	 * Get the block ID
+	 * @return ?int
+	 */
+	public function getId();
+
+	/**
+	 * Get the information that identifies this block, such that a user could
+	 * look up everything that can be found about this block. Typically a scalar ID (integer
+	 * or string), but can also return a list of IDs, or an associative array encoding a composite
+	 * ID. Must be safe to serialize as JSON.
+	 *
+	 * @return mixed Identifying information
+	 */
+	public function getIdentifier();
+
+	/**
+	 * Get the user who applied this block
+	 *
+	 * @return UserIdentity|null user identity or null. May be an external user.
+	 */
+	public function getBlocker(): ?UserIdentity;
+
+	/**
+	 * Get the reason for creating the block.
+	 *
+	 * @return CommentStoreComment
+	 */
+	public function getReasonComment();
+
+	/**
+	 * Get the UserIdentity identifying the blocked user,
+	 * if the target is indeed a user (that is, if getType() returns TYPE_USER).
+	 *
+	 * @return ?UserIdentity
+	 */
+	public function getTargetUserIdentity(): ?UserIdentity;
+
+	/**
+	 * Return the name of the block target as a string.
+	 * Depending on the type returned by get Type(), this could be a user name,
+	 * an IP address or range, an internal ID, etc.
+	 *
+	 * @return string
+	 */
+	public function getTargetName(): string;
+
+	/**
+	 * Determines whether this block is blocking the given target (and only that target).
+	 *
+	 * @param UserIdentity|string $target
+	 *
+	 * @return bool
+	 */
+	public function isBlocking( $target ): bool;
+
+	/**
+	 * Get the block expiry time
+	 *
+	 * @return string
+	 */
+	public function getExpiry();
+
+	/**
+	 * Get the type of target for this particular block.
+	 * @return int|null Block::TYPE_ constant, will never be TYPE_ID
+	 */
+	public function getType();
+
+	/**
+	 * Get the timestamp indicating when the block was created
+	 *
+	 * @return string
+	 */
+	public function getTimestamp();
+
+	/**
+	 * Indicates that the block is a sitewide block. This means the user is
+	 * prohibited from editing any page on the site (other than their own talk
+	 * page).
+	 *
+	 * @return bool
+	 */
+	public function isSitewide();
+
+	/**
+	 * Get the flag indicating whether this block blocks the target from
+	 * creating an account. (Note that the flag may be overridden depending on
+	 * global configs.)
+	 *
+	 * @return bool
+	 */
+	public function isCreateAccountBlocked();
+
+	/**
+	 * Returns whether the block is a hardblock (affects logged-in users on a given IP/range)
+	 *
+	 * Note that users are always hardblocked, since they're logged in by definition.
+	 *
+	 * @return bool
+	 */
+	public function isHardblock();
+
+}
diff --git a/includes/block/BlockErrorFormatter.php b/includes/block/BlockErrorFormatter.php
index 9382f1edd54b..ca224f47a9a9 100644
--- a/includes/block/BlockErrorFormatter.php
+++ b/includes/block/BlockErrorFormatter.php
@@ -49,14 +49,14 @@ class BlockErrorFormatter {
 	 * block features. Message parameters are formatted for the specified user and
 	 * language.
 	 *
-	 * @param AbstractBlock $block
+	 * @param Block $block
 	 * @param UserIdentity $user
 	 * @param Language $language
 	 * @param string $ip
 	 * @return Message
 	 */
 	public function getMessage(
-		AbstractBlock $block,
+		Block $block,
 		UserIdentity $user,
 		Language $language,
 		$ip
@@ -69,7 +69,7 @@ class BlockErrorFormatter {
 	/**
 	 * Get a standard set of block details for building a block error message.
 	 *
-	 * @param AbstractBlock $block
+	 * @param Block $block
 	 * @return mixed[]
 	 *  - identifier: Information for looking up the block
 	 *  - targetName: The target, as a string
@@ -79,12 +79,13 @@ class BlockErrorFormatter {
 	 *  - expiry: Expiry time
 	 *  - timestamp: Time the block was created
 	 */
-	private function getBlockErrorInfo( AbstractBlock $block ) {
+	private function getBlockErrorInfo( Block $block ) {
+		$blocker = $block->getBlocker();
 		return [
 			'identifier' => $block->getIdentifier(),
-			'targetName' => (string)$block->getTarget(),
-			'blockerName' => $block->getByName(),
-			'blockerId' => $block->getBy(),
+			'targetName' => $block->getTargetName(),
+			'blockerName' => $blocker ? $blocker->getName() : '',
+			'blockerId' => $blocker ? $blocker->getId() : 0,
 			'reason' => $block->getReasonComment(),
 			'expiry' => $block->getExpiry(),
 			'timestamp' => $block->getTimestamp(),
@@ -96,13 +97,13 @@ class BlockErrorFormatter {
 	 * formatted for a specified user and language.
 	 *
 	 * @since 1.35
-	 * @param AbstractBlock $block
+	 * @param Block $block
 	 * @param UserIdentity $user
 	 * @param Language $language
 	 * @return mixed[] See getBlockErrorInfo
 	 */
 	private function getFormattedBlockErrorInfo(
-		AbstractBlock $block,
+		Block $block,
 		UserIdentity $user,
 		Language $language
 	) {
@@ -158,13 +159,13 @@ class BlockErrorFormatter {
 	/**
 	 * Determine the block error message key by examining the block.
 	 *
-	 * @param AbstractBlock $block
+	 * @param Block $block
 	 * @return string Message key
 	 */
-	private function getBlockErrorMessageKey( AbstractBlock $block ) {
+	private function getBlockErrorMessageKey( Block $block ) {
 		$key = 'blockedtext';
 		if ( $block instanceof DatabaseBlock ) {
-			if ( $block->getType() === AbstractBlock::TYPE_AUTO ) {
+			if ( $block->getType() === Block::TYPE_AUTO ) {
 				$key = 'autoblockedtext';
 			} elseif ( !$block->isSitewide() ) {
 				$key = 'blockedtext-partial';
@@ -181,7 +182,7 @@ class BlockErrorFormatter {
 	 * Get the formatted parameters needed to build the block error messages handled by
 	 * getBlockErrorMessageKey.
 	 *
-	 * @param AbstractBlock $block
+	 * @param Block $block
 	 * @param UserIdentity $user
 	 * @param Language $language
 	 * @param string $ip
@@ -196,7 +197,7 @@ class BlockErrorFormatter {
 	 *  - timestamp: Time the block was created, in the specified language
 	 */
 	private function getBlockErrorMessageParams(
-		AbstractBlock $block,
+		Block $block,
 		UserIdentity $user,
 		Language $language,
 		$ip
diff --git a/includes/block/BlockPermissionChecker.php b/includes/block/BlockPermissionChecker.php
index f2cb746e8d4e..9bd91540a619 100644
--- a/includes/block/BlockPermissionChecker.php
+++ b/includes/block/BlockPermissionChecker.php
@@ -141,7 +141,7 @@ class BlockPermissionChecker {
 			// Blocked admin is trying to alter their own block
 
 			// Self-blocked admins can always remove or alter their block
-			if ( $block->getByName() === $performerIdentity->getName() ) {
+			if ( $block->getBlocker() && $performerIdentity->equals( $block->getBlocker() ) ) {
 				return true;
 			}
 
@@ -155,7 +155,8 @@ class BlockPermissionChecker {
 
 		if (
 			$this->target instanceof UserIdentity &&
-			$block->getByName() === $this->target->getName()
+			$block->getBlocker() &&
+			$this->target->equals( $block->getBlocker() )
 		) {
 			// T150826: Blocked admins can always block the admin who blocked them
 			return true;
diff --git a/includes/block/BlockUser.php b/includes/block/BlockUser.php
index 8555f8a2dfb4..04f5f90c5057 100644
--- a/includes/block/BlockUser.php
+++ b/includes/block/BlockUser.php
@@ -559,12 +559,12 @@ class BlockUser {
 
 				if ( $priorBlock === null ) {
 					$this->logger->warning( 'Block could not be inserted. No existing block was found.' );
-					return Status::newFatal( 'ipb-block-not-found', $block->getTarget() );
+					return Status::newFatal( 'ipb-block-not-found', $block->getTargetName() );
 				}
 
 				if ( $block->equals( $priorBlock ) ) {
 					// Block settings are equal => user is already blocked
-					return Status::newFatal( 'ipb_already_blocked', $block->getTarget() );
+					return Status::newFatal( 'ipb_already_blocked', $block->getTargetName() );
 				}
 
 				$currentBlock = $this->configureBlock( $priorBlock );
@@ -572,7 +572,7 @@ class BlockUser {
 				$isReblock = true;
 				$block = $currentBlock;
 			} else {
-				return Status::newFatal( 'ipb_already_blocked', $block->getTarget() );
+				return Status::newFatal( 'ipb_already_blocked', $block->getTargetName() );
 			}
 		}
 
diff --git a/includes/block/CompositeBlock.php b/includes/block/CompositeBlock.php
index b333b26ac189..0f898b829640 100644
--- a/includes/block/CompositeBlock.php
+++ b/includes/block/CompositeBlock.php
@@ -22,6 +22,7 @@
 
 namespace MediaWiki\Block;
 
+use MediaWiki\User\UserIdentity;
 use Title;
 
 /**
@@ -206,4 +207,11 @@ class CompositeBlock extends AbstractBlock {
 	public function getByName() {
 		return '';
 	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function getBlocker(): ?UserIdentity {
+		return null;
+	}
 }
diff --git a/includes/block/DatabaseBlock.php b/includes/block/DatabaseBlock.php
index 949c8d1528db..761aa836ecea 100644
--- a/includes/block/DatabaseBlock.php
+++ b/includes/block/DatabaseBlock.php
@@ -391,7 +391,7 @@ class DatabaseBlock extends AbstractBlock {
 			if ( $block->getType() == self::TYPE_RANGE ) {
 				# This is the number of bits that are allowed to vary in the block, give
 				# or take some floating point errors
-				$target = $block->getTarget();
+				$target = $block->getTargetName();
 				$max = IPUtils::isIPv6( $target ) ? 128 : 32;
 				list( $network, $bits ) = IPUtils::parseCIDR( $target );
 				$size = $max - $bits;
@@ -655,13 +655,13 @@ class DatabaseBlock extends AbstractBlock {
 
 		# Make a new block object with the desired properties.
 		$autoblock = new DatabaseBlock;
-		wfDebug( "Autoblocking {$this->getTarget()}@" . $autoblockIP );
+		wfDebug( "Autoblocking {$this->getTargetName()}@" . $autoblockIP );
 		$autoblock->setTarget( $autoblockIP );
 		$autoblock->setBlocker( $this->getBlocker() );
 		$autoblock->setReason(
 			wfMessage(
 				'autoblocker',
-				(string)$this->getTarget(),
+				$this->getTargetName(),
 				$this->getReasonComment()->text
 			)->inContentLanguage()->plain()
 		);
@@ -854,7 +854,7 @@ class DatabaseBlock extends AbstractBlock {
 				wfMessage( 'autoblockid', $this->mId )->text()
 			);
 		} else {
-			return htmlspecialchars( $this->getTarget() );
+			return htmlspecialchars( $this->getTargetName() );
 		}
 	}
 
diff --git a/includes/block/DatabaseBlockStore.php b/includes/block/DatabaseBlockStore.php
index 191579ca17c9..ea5404399715 100644
--- a/includes/block/DatabaseBlockStore.php
+++ b/includes/block/DatabaseBlockStore.php
@@ -29,7 +29,6 @@ use MediaWiki\Config\ServiceOptions;
 use MediaWiki\HookContainer\HookContainer;
 use MediaWiki\HookContainer\HookRunner;
 use MediaWiki\User\ActorStoreFactory;
-use MediaWiki\User\UserIdentity;
 use MWException;
 use Psr\Log\LoggerInterface;
 use ReadOnlyMode;
@@ -342,12 +341,11 @@ class DatabaseBlockStore {
 	) : array {
 		$expiry = $dbw->encodeExpiry( $block->getExpiry() );
 
-		$target = $block->getTarget();
-		$forcedTargetId = $block->getForcedTargetId();
+		$forcedTargetId = $block->getForcedTargetID();
 		if ( $forcedTargetId ) {
 			$userId = $forcedTargetId;
-		} elseif ( $target instanceof User ) {
-			$userId = $target->getId();
+		} elseif ( $block->getTargetUserIdentity() ) {
+			$userId = $block->getTargetUserIdentity()->getId();
 		} else {
 			$userId = 0;
 		}
@@ -360,7 +358,7 @@ class DatabaseBlockStore {
 			->acquireActorId( $block->getBlocker(), $dbw );
 
 		$blockArray = [
-			'ipb_address'          => (string)$target,
+			'ipb_address'          => $block->getTargetName(),
 			'ipb_user'             => $userId,
 			'ipb_by_actor'         => $blockerActor,
 			'ipb_timestamp'        => $dbw->timestamp( $block->getTimestamp() ),
@@ -431,7 +429,7 @@ class DatabaseBlockStore {
 		// If autoblock is enabled, autoblock the LAST IP(s) used
 		if ( $block->isAutoblocking() && $block->getType() == AbstractBlock::TYPE_USER ) {
 			$this->logger->debug(
-				'Doing retroactive autoblocks for ' . $block->getTarget()
+				'Doing retroactive autoblocks for ' . $block->getTargetName()
 			);
 
 			$hookAutoBlocked = [];
@@ -463,12 +461,11 @@ class DatabaseBlockStore {
 			return [];
 		}
 
-		list( $target, $type ) = $block->getTargetAndType();
+		$type = $block->getType();
 		if ( $type !== AbstractBlock::TYPE_USER ) {
 			// Autoblocks only apply to users
 			return [];
 		}
-		/** @var UserIdentity $target */
 
 		$dbr = $this->loadBalancer->getConnectionRef( DB_REPLICA );
 
@@ -477,7 +474,10 @@ class DatabaseBlockStore {
 			'LIMIT' => 1,
 		];
 
-		$actor = $this->actorStoreFactory->getActorNormalization()->findActorId( $target, $dbr );
+		$actor = $this->actorStoreFactory->getActorNormalization()->findActorId(
+			$block->getTargetUserIdentity(),
+			$dbr
+		);
 		if ( !$actor ) {
 			$this->logger->debug( 'No actor found to retroactively autoblock' );
 			return [];
diff --git a/includes/block/SystemBlock.php b/includes/block/SystemBlock.php
index e99d076f09fb..318cc1ab05d9 100644
--- a/includes/block/SystemBlock.php
+++ b/includes/block/SystemBlock.php
@@ -22,6 +22,8 @@
 
 namespace MediaWiki\Block;
 
+use MediaWiki\User\UserIdentity;
+
 /**
  * System blocks are temporary blocks that are created on enforcement (e.g.
  * from IP lists) and are not saved to the database. The target of a
@@ -107,4 +109,11 @@ class SystemBlock extends AbstractBlock {
 	public function getByName() {
 		return '';
 	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function getBlocker(): ?UserIdentity {
+		return null;
+	}
 }
diff --git a/includes/block/UnblockUser.php b/includes/block/UnblockUser.php
index 85a69864c450..92b0e9263b7b 100644
--- a/includes/block/UnblockUser.php
+++ b/includes/block/UnblockUser.php
@@ -31,7 +31,6 @@ use MediaWiki\User\UserIdentity;
 use RevisionDeleteUser;
 use Status;
 use TitleValue;
-use User;
 
 /**
  * Backend class for unblocking users
@@ -175,7 +174,7 @@ class UnblockUser {
 			$this->block->getType() === AbstractBlock::TYPE_RANGE &&
 			$this->targetType === AbstractBlock::TYPE_IP
 		) {
-			$status->fatal( 'ipb_blocked_as_range', $this->target, $this->block->getTarget() );
+			$status->fatal( 'ipb_blocked_as_range', $this->target, $this->block->getTargetName() );
 			return $status;
 		}
 
@@ -190,17 +189,17 @@ class UnblockUser {
 
 		$deleteBlockStatus = $this->blockStore->deleteBlock( $this->block );
 		if ( !$deleteBlockStatus ) {
-			$status->fatal( 'ipb_cant_unblock', $this->block->getTarget() );
+			$status->fatal( 'ipb_cant_unblock', $this->block->getTargetName() );
 			return $status;
 		}
 
 		$this->hookRunner->onUnblockUserComplete( $this->block, $legacyUser );
 
 		// Unset _deleted fields as needed
-		if ( $this->block->getHideName() && $this->block->getTarget() instanceof User ) {
-			// Something is deeply FUBAR if this is not a User object, but who knows?
-			$id = $this->block->getTarget()->getId();
-			RevisionDeleteUser::unsuppressUserName( $this->block->getTarget(), $id );
+		$user = $this->block->getTargetUserIdentity();
+		if ( $this->block->getHideName() && $user ) {
+			$id = $user->getId();
+			RevisionDeleteUser::unsuppressUserName( $user->getName(), $id );
 		}
 
 		$this->log();
@@ -217,9 +216,7 @@ class UnblockUser {
 		if ( $this->block->getType() === DatabaseBlock::TYPE_AUTO ) {
 			$page = TitleValue::tryNew( NS_USER, '#' . $this->block->getId() );
 		} else {
-			$page = $this->block->getTarget() instanceof UserIdentity
-				? $this->block->getTarget()->getUserPage()
-				: TitleValue::tryNew( NS_USER, $this->block->getTarget() );
+			$page = TitleValue::tryNew( NS_USER, $this->block->getTargetName() );
 		}
 
 		$logEntry = new ManualLogEntry( 'block', 'unblock' );
diff --git a/includes/exception/UserBlockedError.php b/includes/exception/UserBlockedError.php
index 48c34791f1d8..a2d429a9fb59 100644
--- a/includes/exception/UserBlockedError.php
+++ b/includes/exception/UserBlockedError.php
@@ -18,7 +18,7 @@
  * @file
  */
 
-use MediaWiki\Block\AbstractBlock;
+use MediaWiki\Block\Block;
 use MediaWiki\MediaWikiServices;
 use MediaWiki\User\UserIdentity;
 
@@ -32,13 +32,13 @@ use MediaWiki\User\UserIdentity;
 class UserBlockedError extends ErrorPageError {
 	/**
 	 * @stable to call
-	 * @param AbstractBlock $block
+	 * @param Block $block
 	 * @param UserIdentity|null $user
 	 * @param Language|null $language
 	 * @param string|null $ip
 	 */
 	public function __construct(
-		AbstractBlock $block,
+		Block $block,
 		UserIdentity $user = null,
 		Language $language = null,
 		$ip = null
diff --git a/includes/page/Article.php b/includes/page/Article.php
index 81052b26b2da..2fa523ead84e 100644
--- a/includes/page/Article.php
+++ b/includes/page/Article.php
@@ -1382,7 +1382,7 @@ class Article implements Page {
 					$outputPage,
 					'block',
 					$services->getNamespaceInfo()->getCanonicalName( NS_USER ) . ':' .
-						$block->getTarget(),
+						$block->getTargetName(),
 					'',
 					[
 						'lim' => 1,
diff --git a/includes/specials/SpecialBlock.php b/includes/specials/SpecialBlock.php
index bda4016d18df..e3d21f503233 100644
--- a/includes/specials/SpecialBlock.php
+++ b/includes/specials/SpecialBlock.php
@@ -432,11 +432,14 @@ class SpecialBlock extends FormSpecialPage {
 
 		$block = DatabaseBlock::newFromTarget( $this->target );
 
+		// UserIdentity object if possible, string otherwise. Like $this->target
+		$blockTarget = $block ? ( $block->getTargetUserIdentity() ?: $block->getTargetName() ) : null;
+
 		// Populate fields if there is a block that is not an autoblock; if it is a range
 		// block, only populate the fields if the range is the same as $this->target
 		if ( $block instanceof DatabaseBlock && $block->getType() !== DatabaseBlock::TYPE_AUTO
 			&& ( $this->type != DatabaseBlock::TYPE_RANGE
-				|| $block->getTarget() == $this->target )
+				|| ( $this->target && $block->isBlocking( $this->target ) ) )
 		) {
 			$fields['HardBlock']['default'] = $block->isHardblock();
 			$fields['CreateAccount']['default'] = $block->isCreateAccountBlocked();
@@ -519,7 +522,7 @@ class SpecialBlock extends FormSpecialPage {
 			}
 
 			$this->alreadyBlocked = true;
-			$this->preErrors[] = [ 'ipb-needreblock', wfEscapeWikiText( (string)$block->getTarget() ) ];
+			$this->preErrors[] = [ 'ipb-needreblock', wfEscapeWikiText( $block->getTargetName() ) ];
 		}
 
 		if ( $this->alreadyBlocked || $this->getRequest()->wasPosted()
diff --git a/includes/specials/SpecialContributions.php b/includes/specials/SpecialContributions.php
index fe86983af611..f4ad5738de91 100644
--- a/includes/specials/SpecialContributions.php
+++ b/includes/specials/SpecialContributions.php
@@ -449,7 +449,8 @@ class SpecialContributions extends IncludableSpecialPage {
 
 				if ( $block !== null && $block->getType() != DatabaseBlock::TYPE_AUTO ) {
 					if ( $block->getType() == DatabaseBlock::TYPE_RANGE ) {
-						$nt = $this->namespaceInfo->getCanonicalName( NS_USER ) . ':' . $block->getTarget();
+						$nt = $this->namespaceInfo->getCanonicalName( NS_USER )
+							. ':' . $block->getTargetName();
 					}
 
 					$out = $this->getOutput(); // showLogExtract() wants first parameter by reference
diff --git a/includes/specials/SpecialDeletedContributions.php b/includes/specials/SpecialDeletedContributions.php
index 1daae03d5a79..c33d455a4e1d 100644
--- a/includes/specials/SpecialDeletedContributions.php
+++ b/includes/specials/SpecialDeletedContributions.php
@@ -229,7 +229,8 @@ class SpecialDeletedContributions extends SpecialPage {
 			$block = DatabaseBlock::newFromTarget( $userObj, $userObj );
 			if ( $block !== null && $block->getType() != DatabaseBlock::TYPE_AUTO ) {
 				if ( $block->getType() == DatabaseBlock::TYPE_RANGE ) {
-					$nt = $this->namespaceInfo->getCanonicalName( NS_USER ) . ':' . $block->getTarget();
+					$nt = $this->namespaceInfo->getCanonicalName( NS_USER )
+						. ':' . $block->getTargetName();
 				}
 
 				// LogEventsList::showLogExtract() wants the first parameter by ref
diff --git a/includes/specials/SpecialUnblock.php b/includes/specials/SpecialUnblock.php
index 2e8f6eaff8a5..e0fc7832a52c 100644
--- a/includes/specials/SpecialUnblock.php
+++ b/includes/specials/SpecialUnblock.php
@@ -175,7 +175,8 @@ class SpecialUnblock extends SpecialPage {
 		];
 
 		if ( $this->block instanceof DatabaseBlock ) {
-			list( $target, $type ) = $this->block->getTargetAndType();
+			$type = $this->block->getType();
+			$targetName = $this->block->getTargetName();
 
 			# Autoblocks are logged as "autoblock #123 because the IP was recently used by
 			# User:Foo, and we've just got any block, auto or not, that applies to a target
@@ -185,26 +186,26 @@ class SpecialUnblock extends SpecialPage {
 				$fields['Target']['default'] = $this->target;
 				unset( $fields['Name'] );
 			} else {
-				$fields['Target']['default'] = $target;
+				$fields['Target']['default'] = $targetName;
 				$fields['Target']['type'] = 'hidden';
 				switch ( $type ) {
 					case DatabaseBlock::TYPE_IP:
 						$fields['Name']['default'] = $this->getLinkRenderer()->makeKnownLink(
-							$this->getSpecialPageFactory()->getTitleForAlias( 'Contributions/' . $target->getName() ),
-							$target->getName()
+							$this->getSpecialPageFactory()->getTitleForAlias( 'Contributions/' . $targetName ),
+							$targetName
 						);
 						$fields['Name']['raw'] = true;
 						break;
 					case DatabaseBlock::TYPE_USER:
 						$fields['Name']['default'] = $this->getLinkRenderer()->makeLink(
-							$target->getUserPage(),
-							$target->getName()
+							new TitleValue( NS_USER, $targetName ),
+							$targetName
 						);
 						$fields['Name']['raw'] = true;
 						break;
 
 					case DatabaseBlock::TYPE_RANGE:
-						$fields['Name']['default'] = $target;
+						$fields['Name']['default'] = $targetName;
 						break;
 
 					case DatabaseBlock::TYPE_AUTO:
diff --git a/tests/phpunit/includes/block/DatabaseBlockTest.php b/tests/phpunit/includes/block/DatabaseBlockTest.php
index 5dbb156e9421..335780efd34b 100644
--- a/tests/phpunit/includes/block/DatabaseBlockTest.php
+++ b/tests/phpunit/includes/block/DatabaseBlockTest.php
@@ -318,7 +318,15 @@ class DatabaseBlockTest extends MediaWikiLangTestCase {
 			$block->getTarget()->getName(),
 			'Correct blockee name'
 		);
+		$this->assertEquals(
+			'UserOnForeignWiki',
+			$block->getTargetUserIdentity()->getName(),
+			'Correct blockee name'
+		);
 		$this->assertEquals( $userId, $block->getTarget()->getId(), 'Correct blockee id' );
+		$this->assertEquals( $userId, $block->getTargetUserIdentity()->getId(), 'Correct blockee id' );
+		$this->assertEquals( 'UserOnForeignWiki', $block->getTargetName(), 'Correct blockee name' );
+		$this->assertTrue( $block->isBlocking( 'UserOnForeignWiki' ), 'Is blocking blockee' );
 		$this->assertEquals( 'Meta>MetaWikiUser', $block->getBlocker()->getName(),
 			'Correct blocker name' );
 		$this->assertEquals( 'Meta>MetaWikiUser', $block->getByName(), 'Correct blocker name' );
@@ -485,6 +493,9 @@ class DatabaseBlockTest extends MediaWikiLangTestCase {
 		$this->assertInstanceOf( DatabaseBlock::class, $block );
 		$this->assertEquals( $block->getBy(), $sysop->getId() );
 		$this->assertEquals( $block->getTarget()->getName(), $badActor->getName() );
+		$this->assertEquals( $block->getTargetName(), $badActor->getName() );
+		$this->assertTrue( $block->isBlocking( $badActor ), 'Is blocking expected user' );
+		$this->assertEquals( $block->getTargetUserIdentity()->getId(), $badActor->getId() );
 		$blockStore->deleteBlock( $block );
 	}
 
diff --git a/tests/phpunit/unit/includes/block/BlockPermissionCheckerTest.php b/tests/phpunit/unit/includes/block/BlockPermissionCheckerTest.php
index 8a0f15459a4e..a5ec1b4901e7 100644
--- a/tests/phpunit/unit/includes/block/BlockPermissionCheckerTest.php
+++ b/tests/phpunit/unit/includes/block/BlockPermissionCheckerTest.php
@@ -74,10 +74,10 @@ class BlockPermissionCheckerTest extends MediaWikiUnitTestCase {
 		// Mock DatabaseBlock instead of AbstractBlock because its easier
 		$block = $this->createNoOpMock(
 			DatabaseBlock::class,
-			[ 'isSitewide', 'getByName' ]
+			[ 'isSitewide', 'getBlocker' ]
 		);
 		$block->method( 'isSitewide' )->willReturn( $isSitewide );
-		$block->method( 'getByName' )->willReturn( $byName );
+		$block->method( 'getBlocker' )->willReturn( new UserIdentityValue( 7, $byName ) );
 		return $block;
 	}
 
@@ -181,6 +181,9 @@ class BlockPermissionCheckerTest extends MediaWikiUnitTestCase {
 		$user->method( 'getBlock' )->willReturn( $block );
 		$user->method( 'getId' )->willReturn( 1 );
 		$user->method( 'getName' )->willReturn( 'blocker' );
+		$user->method( 'equals' )->willReturnCallback( static function ( $user ) {
+			return $user->getName() === 'blocker';
+		} );
 
 		$target = new UserIdentityValue( $targetUserId, $targetUserName );