fix: pagination adjusts correctly after table deletes

examples/bootstrap4/app.py

@@ -271,10 +271,32 @@ def edit_message(message_id):
 def delete_message(message_id):
     message = Message.query.get(message_id)
     if message:
+        # Get current page from referrer or request args
+        current_page = request.args.get('page', 1, type=int)
+        if request.referrer and 'page=' in request.referrer:
+            # Extract page number from referrer URL
+            import re
+            page_match = re.search(r'[?&]page=(\d+)', request.referrer)
+            if page_match:
+                current_page = int(page_match.group(1))
+
+        # Delete the message
         db.session.delete(message)
         db.session.commit()
-        return f'Message {message_id} has been deleted. Return to <a href="/table">table</a>.'
-    return f'Message {message_id} did not exist and could therefore not be deleted. Return to <a href="/table">table</a>.'
+
+        # Calculate total remaining messages and pages
+        total_messages = Message.query.count()
+        per_page = 10  # Same as used in test_table route
+        total_pages = max(1, (total_messages + per_page - 1) // per_page)  # At least page 1
+
+        # Determine which page to redirect to
+        redirect_page = min(current_page, total_pages)
+
+        flash(f'Message {message_id} has been deleted.', 'success')
+        return redirect(url_for('test_table', page=redirect_page))
+    else:
+        flash(f'Message {message_id} did not exist and could therefore not be deleted.', 'warning')
+        return redirect(url_for('test_table'))
 
 
 @app.route('/table/<int:message_id>/like')

examples/bootstrap5/app.py

@@ -295,10 +295,32 @@ def edit_message(message_id):
 def delete_message(message_id):
     message = Message.query.get(message_id)
     if message:
+        # Get current page from referrer or request args
+        current_page = request.args.get('page', 1, type=int)
+        if request.referrer and 'page=' in request.referrer:
+            # Extract page number from referrer URL
+            import re
+            page_match = re.search(r'[?&]page=(\d+)', request.referrer)
+            if page_match:
+                current_page = int(page_match.group(1))
+
+        # Delete the message
         db.session.delete(message)
         db.session.commit()
-        return f'Message {message_id} has been deleted. Return to <a href="/table">table</a>.'
-    return f'Message {message_id} did not exist and could therefore not be deleted. Return to <a href="/table">table</a>.'
+
+        # Calculate total remaining messages and pages
+        total_messages = Message.query.count()
+        per_page = 10  # Same as used in test_table route
+        total_pages = max(1, (total_messages + per_page - 1) // per_page)  # At least page 1
+
+        # Determine which page to redirect to
+        redirect_page = min(current_page, total_pages)
+
+        flash(f'Message {message_id} has been deleted.', 'success')
+        return redirect(url_for('test_table', page=redirect_page))
+    else:
+        flash(f'Message {message_id} did not exist and could therefore not be deleted.', 'warning')
+        return redirect(url_for('test_table'))
 
 
 @app.route('/table/<int:message_id>/like')

tests/test_bootstrap4/test_render_pagination.py

@@ -1,4 +1,4 @@
-from flask import render_template_string, request
+from flask import render_template_string, request, redirect, url_for, flash
 from flask_sqlalchemy import SQLAlchemy
 
 
@@ -36,3 +36,108 @@ def test():
     assert '1</a>' in data
     assert '<a class="page-link" href="#">2 <span class="sr-only">(current)</span></a>' in data
     assert '10</a>' in data
+
+
+def test_pagination_after_delete(app, client):  # noqa: C901
+    """Test that pagination works correctly after deleting items."""
+    db = SQLAlchemy(app)
+
+    class Message(db.Model):
+        id = db.Column(db.Integer, primary_key=True)
+        text = db.Column(db.String(100))
+
+    @app.route('/table')
+    def test_table():
+        page = request.args.get('page', 1, type=int)
+        pagination = Message.query.paginate(page=page, per_page=10)
+        messages = pagination.items
+        return render_template_string('''
+            Page {{ pagination.page }} of {{ pagination.pages }}
+            Total: {{ pagination.total }}
+            Messages: {{ messages|length }}
+        ''', pagination=pagination, messages=messages)
+
+    @app.route('/table/<int:message_id>/delete', methods=['POST'])
+    def delete_message(message_id):
+        message = Message.query.get(message_id)
+        if message:
+            # Get current page from request args or referrer
+            current_page = request.args.get('page', 1, type=int)
+            if request.referrer and 'page=' in request.referrer:
+                import re
+                page_match = re.search(r'[?&]page=(\d+)', request.referrer)
+                if page_match:
+                    current_page = int(page_match.group(1))
+
+            # Delete the message
+            db.session.delete(message)
+            db.session.commit()
+
+            # Calculate total remaining messages and pages
+            total_messages = Message.query.count()
+            per_page = 10
+            total_pages = (total_messages + per_page - 1) // per_page if total_messages > 0 else 1
+
+            # Determine which page to redirect to
+            redirect_page = current_page
+            if total_pages == 0 or total_messages == 0:
+                redirect_page = 1
+            elif current_page > total_pages:
+                redirect_page = total_pages
+
+            flash(f'Message {message_id} has been deleted.', 'success')
+            return redirect(url_for('test_table', page=redirect_page))
+        else:
+            flash(f'Message {message_id} did not exist.', 'warning')
+            return redirect(url_for('test_table'))
+
+    with app.app_context():
+        # Test Case 1: Delete from middle page - should stay on same page
+        db.drop_all()
+        db.create_all()
+        for i in range(25):  # Create 25 messages (3 pages of 10 each, 5 on last page)
+            msg = Message(text=f'Message {i+1}')
+            db.session.add(msg)
+        db.session.commit()
+
+        # Go to page 2 and delete a message
+        response = client.get('/table?page=2')
+        assert 'Page 2 of 3' in response.get_data(as_text=True)
+
+        # Delete message ID 15 (should be on page 2)
+        response = client.post('/table/15/delete?page=2', follow_redirects=True)
+        data = response.get_data(as_text=True)
+        assert 'Page 2 of 3' in data  # Should still be on page 2
+        assert 'Total: 24' in data     # One less message
+
+        # Test Case 2: Delete all items from last page - should redirect to previous page
+        db.drop_all()
+        db.create_all()
+        for i in range(21):  # Create 21 messages (3 pages: 10, 10, 1)
+            msg = Message(text=f'Message {i+1}')
+            db.session.add(msg)
+        db.session.commit()
+
+        # Go to page 3 (last page with 1 item)
+        response = client.get('/table?page=3')
+        data = response.get_data(as_text=True)
+        assert 'Page 3 of 3' in data
+        assert 'Total: 21' in data
+
+        # Delete the only message on page 3
+        response = client.post('/table/21/delete?page=3', follow_redirects=True)
+        data = response.get_data(as_text=True)
+        assert 'Page 2 of 2' in data  # Should redirect to page 2
+        assert 'Total: 20' in data     # One less message
+
+        # Test Case 3: Delete all messages - should go to page 1
+        db.drop_all()
+        db.create_all()
+        msg = Message(text='Last message')
+        db.session.add(msg)
+        db.session.commit()
+
+        response = client.post('/table/1/delete', follow_redirects=True)
+        data = response.get_data(as_text=True)
+        assert 'Page 1 of' in data  # Should be on page 1 (could be "Page 1 of 0" or "Page 1 of 1")
+        assert 'Total: 0' in data     # No messages left

tests/test_bootstrap5/test_pagination.py

@@ -1,4 +1,4 @@
-from flask import render_template_string, request
+from flask import render_template_string, request, redirect, url_for, flash
 from flask_sqlalchemy import SQLAlchemy
 
 
@@ -30,3 +30,108 @@ def test():
     assert '<a class="page-link" href="#">1 <span class="sr-only">(current)</span></a>' not in data
     assert '<li class="page-item active" aria-current="page">' in data
     assert '<a class="page-link" href="#">1</a>' in data
+
+
+def test_pagination_after_delete(app, client):  # noqa: C901
+    """Test that pagination works correctly after deleting items."""
+    db = SQLAlchemy(app)
+
+    class Message(db.Model):
+        id = db.Column(db.Integer, primary_key=True)
+        text = db.Column(db.String(100))
+
+    @app.route('/table')
+    def test_table():
+        page = request.args.get('page', 1, type=int)
+        pagination = Message.query.paginate(page=page, per_page=10)
+        messages = pagination.items
+        return render_template_string('''
+            Page {{ pagination.page }} of {{ pagination.pages }}
+            Total: {{ pagination.total }}
+            Messages: {{ messages|length }}
+        ''', pagination=pagination, messages=messages)
+
+    @app.route('/table/<int:message_id>/delete', methods=['POST'])
+    def delete_message(message_id):
+        message = Message.query.get(message_id)
+        if message:
+            # Get current page from request args or referrer
+            current_page = request.args.get('page', 1, type=int)
+            if request.referrer and 'page=' in request.referrer:
+                import re
+                page_match = re.search(r'[?&]page=(\d+)', request.referrer)
+                if page_match:
+                    current_page = int(page_match.group(1))
+
+            # Delete the message
+            db.session.delete(message)
+            db.session.commit()
+
+            # Calculate total remaining messages and pages
+            total_messages = Message.query.count()
+            per_page = 10
+            total_pages = (total_messages + per_page - 1) // per_page if total_messages > 0 else 1
+
+            # Determine which page to redirect to
+            redirect_page = current_page
+            if total_pages == 0 or total_messages == 0:
+                redirect_page = 1
+            elif current_page > total_pages:
+                redirect_page = total_pages
+
+            flash(f'Message {message_id} has been deleted.', 'success')
+            return redirect(url_for('test_table', page=redirect_page))
+        else:
+            flash(f'Message {message_id} did not exist.', 'warning')
+            return redirect(url_for('test_table'))
+
+    with app.app_context():
+        # Test Case 1: Delete from middle page - should stay on same page
+        db.drop_all()
+        db.create_all()
+        for i in range(25):  # Create 25 messages (3 pages of 10 each, 5 on last page)
+            msg = Message(text=f'Message {i+1}')
+            db.session.add(msg)
+        db.session.commit()
+
+        # Go to page 2 and delete a message
+        response = client.get('/table?page=2')
+        assert 'Page 2 of 3' in response.get_data(as_text=True)
+
+        # Delete message ID 15 (should be on page 2)
+        response = client.post('/table/15/delete?page=2', follow_redirects=True)
+        data = response.get_data(as_text=True)
+        assert 'Page 2 of 3' in data  # Should still be on page 2
+        assert 'Total: 24' in data     # One less message
+
+        # Test Case 2: Delete all items from last page - should redirect to previous page
+        db.drop_all()
+        db.create_all()
+        for i in range(21):  # Create 21 messages (3 pages: 10, 10, 1)
+            msg = Message(text=f'Message {i+1}')
+            db.session.add(msg)
+        db.session.commit()
+
+        # Go to page 3 (last page with 1 item)
+        response = client.get('/table?page=3')
+        data = response.get_data(as_text=True)
+        assert 'Page 3 of 3' in data
+        assert 'Total: 21' in data
+
+        # Delete the only message on page 3
+        response = client.post('/table/21/delete?page=3', follow_redirects=True)
+        data = response.get_data(as_text=True)
+        assert 'Page 2 of 2' in data  # Should redirect to page 2
+        assert 'Total: 20' in data     # One less message
+
+        # Test Case 3: Delete all messages - should go to page 1
+        db.drop_all()
+        db.create_all()
+        msg = Message(text='Last message')
+        db.session.add(msg)
+        db.session.commit()
+
+        response = client.post('/table/1/delete', follow_redirects=True)
+        data = response.get_data(as_text=True)
+        assert 'Page 1 of' in data  # Should be on page 1 (could be "Page 1 of 0" or "Page 1 of 1")
+        assert 'Total: 0' in data     # No messages left