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Media: Skip server-side scaling during client-side media processing #12689

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2c996a0
Media: Skip server-side scaling during client-side media processing.
itzmekhokan Jul 25, 2026
292c578
Media: Cover the sub-size naming and orphaned file symptoms in client…
itzmekhokan Aug 3, 2026
ba0d8cb
Merge branch 'trunk' into fix/65708-heic-orphaned-scaled-file
adamsilverstein Aug 3, 2026
1bc2c67
Merge branch 'trunk' into fix/65708-heic-orphaned-scaled-file
adamsilverstein Aug 4, 2026
1db1031
Merge branch 'trunk' into fix/65708-heic-orphaned-scaled-file
adamsilverstein Aug 4, 2026
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5 changes: 5 additions & 0 deletions src/wp-includes/rest-api/endpoints/class-wp-rest-attachments-controller.php
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Original file line number Diff line number Diff line change
Expand Up @@ -459,6 +459,10 @@ public function create_item( $request ) {
// Disable server-side EXIF rotation so the client can handle it.
// This preserves the original orientation value in the metadata.
add_filter( 'wp_image_maybe_exif_rotate', '__return_false', 100 );
// Disable server-side "big image" downscaling; the client supplies its
// own scaled version via the sideload endpoint. Scaling here would
// create a conflicting "-scaled" file and orphan the full-size upload.
add_filter( 'big_image_size_threshold', '__return_false', 100 );
}

// Handle convert_format parameter.
Expand Down Expand Up @@ -691,6 +695,7 @@ private function remove_client_side_media_processing_filters(): void {
remove_filter( 'fallback_intermediate_image_sizes', '__return_empty_array', 100 );
remove_filter( 'wp_image_maybe_exif_rotate', '__return_false', 100 );
remove_filter( 'image_editor_output_format', '__return_empty_array', 100 );
remove_filter( 'big_image_size_threshold', '__return_false', 100 );
}

/**
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169 changes: 169 additions & 0 deletions tests/phpunit/tests/rest-api/rest-attachments-controller.php
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Original file line number Diff line number Diff line change
Expand Up @@ -3875,6 +3875,175 @@ public function test_sideload_scaled_image() {
$this->assertGreaterThan( 0, $metadata['filesize'], 'Filesize should be positive.' );
}

/**
* When the client generates sub-sizes (generate_sub_sizes is false), the
* server must not perform its own "big image" downscaling on upload.
*
* Otherwise the server creates a `-scaled` file and records the upload as
* `original_image`. The client's subsequent scaled sideload then collides
* with that `-scaled` file and is renamed `-scaled-1`, the thumbnails
* inherit the numbered name, and the server-generated full-size file is
* left orphaned on disk.
*
* @ticket 65708
* @requires function imagejpeg
*/
public function test_create_item_skips_big_image_scaling_when_client_generates_sub_sizes() {
$this->enable_client_side_media_processing();

wp_set_current_user( self::$author_id );

// Force the threshold below the image's dimensions so scaling would be
// triggered were it not suppressed for client-side processing.
add_filter(
'big_image_size_threshold',
static function () {
return 1000;
}
);

// Upload a large image with the client handling sub-size generation.
$request = new WP_REST_Request( 'POST', '/wp/v2/media' );
$request->set_header( 'Content-Type', 'image/jpeg' );
$request->set_header( 'Content-Disposition', 'attachment; filename=33772.jpg' );
$request->set_param( 'generate_sub_sizes', false );
$request->set_body( file_get_contents( DIR_TESTDATA . '/images/33772.jpg' ) );
$response = rest_get_server()->dispatch( $request );
$data = $response->get_data();
$attachment_id = $data['id'];

$this->assertSame( 201, $response->get_status(), 'Uploading the image should succeed.' );

// The uploaded full-size image should be stored untouched: no
// server-side "-scaled" file and no original_image swap.
$original_file = get_attached_file( $attachment_id, true );
$original_basename = wp_basename( $original_file );
$original_name_stem = pathinfo( $original_basename, PATHINFO_FILENAME );
$this->assertStringNotContainsString( '-scaled', $original_basename, 'The server should not create a -scaled file when the client generates sub-sizes.' );

$metadata = wp_get_attachment_metadata( $attachment_id );
$this->assertArrayNotHasKey( 'original_image', $metadata, 'The server should not record an original_image when it does not scale the upload.' );

// The client's scaled sideload should now record the untouched upload as
// original_image and keep the -scaled name without a numeric suffix.
$request = new WP_REST_Request( 'POST', "/wp/v2/media/{$attachment_id}/sideload" );
$request->set_header( 'Content-Type', 'image/jpeg' );
$request->set_header( 'Content-Disposition', "attachment; filename={$original_name_stem}-scaled.jpg" );
$request->set_param( 'image_size', 'scaled' );
$request->set_body( file_get_contents( DIR_TESTDATA . '/images/33772.jpg' ) );
$response = rest_get_server()->dispatch( $request );

$this->assertSame( 200, $response->get_status(), 'Sideloading the scaled image should succeed.' );

$sub_size = $response->get_data();
$this->assertSame( $original_basename, $sub_size['original_image'], 'The untouched upload should be recorded as original_image.' );
$this->assertSame( "{$original_name_stem}-scaled.jpg", wp_basename( $sub_size['file'] ), 'The scaled sideload should keep the -scaled name without a numeric collision suffix.' );
}

/**
* The complete client-side flow for an image over the "big image" threshold
* should write only files that the metadata tracks, so that deleting the
* attachment removes all of them.
*
* When the server scales the upload as well, its own full-size file is
* never referenced by the metadata and survives "Delete Permanently", the
* client's scaled sideload collides with the server's "-scaled" file and is
* stored as "-scaled-1", and the sub-sizes inherit the numbered name.
*
* @ticket 65708
* @covers WP_REST_Attachments_Controller::create_item
* @covers WP_REST_Attachments_Controller::sideload_item
* @covers WP_REST_Attachments_Controller::finalize_item
* @requires function imagejpeg
*/
public function test_client_side_big_image_flow_leaves_no_orphaned_files() {
$this->enable_client_side_media_processing();

wp_set_current_user( self::$author_id );

// Force the threshold below the uploaded image's dimensions so scaling
// would be triggered were it not suppressed for client-side processing.
add_filter(
'big_image_size_threshold',
static function () {
return 1000;
}
);

$upload_dir = wp_upload_dir();
$files_before = (array) glob( $upload_dir['path'] . '/*' );

// 1. Upload the full-size image; the client owns all the derivatives.
// 33772.jpg is 1920x1080, so it exceeds the threshold above.
$request = new WP_REST_Request( 'POST', '/wp/v2/media' );
$request->set_header( 'Content-Type', 'image/jpeg' );
$request->set_header( 'Content-Disposition', 'attachment; filename=big-photo.jpg' );
$request->set_param( 'generate_sub_sizes', false );
$request->set_body( file_get_contents( DIR_TESTDATA . '/images/33772.jpg' ) );
$response = rest_get_server()->dispatch( $request );
$attachment_id = $response->get_data()['id'];

$this->assertSame( 201, $response->get_status(), 'Uploading the image should succeed.' );

/*
* 2. Sideload a thumbnail, as the client does for each sub-size. The
* client names it after the file it uploaded, so a server-side
* rename of that file is what pushes this into a collision.
* test-image.jpg is 50x50, within the registered thumbnail maximum.
*/
$request = new WP_REST_Request( 'POST', "/wp/v2/media/{$attachment_id}/sideload" );
$request->set_header( 'Content-Type', 'image/jpeg' );
$request->set_header( 'Content-Disposition', 'attachment; filename=big-photo-150x150.jpg' );
$request->set_param( 'image_size', 'thumbnail' );
$request->set_body( file_get_contents( DIR_TESTDATA . '/images/test-image.jpg' ) );
$response = rest_get_server()->dispatch( $request );
$thumbnail_data = $response->get_data();

$this->assertSame( 200, $response->get_status(), 'Sideloading the thumbnail should succeed.' );
$this->assertSame( 'big-photo-150x150.jpg', wp_basename( $thumbnail_data['file'] ), 'The thumbnail should not inherit a numeric collision suffix.' );

// 3. Sideload the scaled full-size image. canola.jpg is 640x480, the
// size the client would have downscaled the upload to.
$request = new WP_REST_Request( 'POST', "/wp/v2/media/{$attachment_id}/sideload" );
$request->set_header( 'Content-Type', 'image/jpeg' );
$request->set_header( 'Content-Disposition', 'attachment; filename=big-photo-scaled.jpg' );
$request->set_param( 'image_size', 'scaled' );
$request->set_body( file_get_contents( self::$test_file ) );
$response = rest_get_server()->dispatch( $request );
$scaled_data = $response->get_data();

$this->assertSame( 200, $response->get_status(), 'Sideloading the scaled image should succeed.' );

// 4. Finalize, which writes the collected sub-size metadata in one pass.
$request = new WP_REST_Request( 'POST', "/wp/v2/media/{$attachment_id}/finalize" );
$request->set_param( 'sub_sizes', array( $thumbnail_data, $scaled_data ) );
$response = rest_get_server()->dispatch( $request );

$this->assertSame( 200, $response->get_status(), 'Finalize should succeed.' );

$metadata = wp_get_attachment_metadata( $attachment_id );

$this->assertSame( 'big-photo.jpg', $metadata['original_image'], 'The untouched upload should be recorded as original_image.' );
$this->assertSame( 'big-photo-scaled.jpg', wp_basename( $metadata['file'] ), 'The client-supplied scaled image should become the attached file.' );
$this->assertSame( 'big-photo-150x150.jpg', $metadata['sizes']['thumbnail']['file'], 'The thumbnail should keep its dimension-based name.' );

// Every file written for this attachment must be reachable from the
// metadata, otherwise it is orphaned on disk.
$written = array_map( 'wp_basename', array_diff( (array) glob( $upload_dir['path'] . '/*' ), $files_before ) );
sort( $written );
$this->assertSame(
array( 'big-photo-150x150.jpg', 'big-photo-scaled.jpg', 'big-photo.jpg' ),
$written,
'The flow should write only the full-size upload, its scaled copy, and the sub-sizes.'
);

// Deleting the attachment should therefore clean all of them up.
wp_delete_attachment( $attachment_id, true );

$remaining = array_diff( (array) glob( $upload_dir['path'] . '/*' ), $files_before );
$this->assertSame( array(), array_values( $remaining ), 'Deleting the attachment should leave no files behind.' );
}

/**
* Tests that sideloading scaled image requires authentication.
*
Expand Down
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