Changelog

All notable changes to this project will be documented in this file.

[6.1.0] - 2026-05-02

This release is primarily a security and bug-fix update. All users are encouraged to update.

Fixed

• removetags filter: tag names containing regex metacharacters no longer panic the renderer.
• {% cycle %} tag: cycle index is now tracked per template execution instead of mutated on the parsed AST node. Concurrent renders of a cached template no longer race, and sequential renders no longer leak state from a previous execution.
• {% ifchanged %} tag: lastValues/lastContent are now tracked per template execution instead of mutated on the parsed AST node, fixing both a data race under concurrent renders and state leaking between sequential renders of a cached template.
• {% ifchanged %} tag: rendering an {% ifchanged %} block without an {% else %} branch no longer crashes with a nil-pointer dereference when the watched value is unchanged. Matches Django's behavior of producing no output.
• {% filter %} tag: BanFilter is now enforced inside {% filter %} blocks.

Changed

• {% ssi %} plaintext mode now reads the included file through the configured TemplateLoader chain instead of ioutil.ReadFile, so non-filesystem loaders (FSLoader, HttpFilesystemLoader, custom) can serve SSI content.
• Template error reporting (RawLine) now reads source lines through the template's loader chain instead of opening files directly with os.Open. Error line extraction now works for any TemplateLoader.

Removed

• SandboxedFilesystemLoader and NewSandboxedFilesystemLoader have been removed. They were marked WIP, never wired into any enforcement path, and behaved as a thin pass-through to LocalFilesystemLoader. Callers should use LocalFilesystemLoader directly; sandboxing should be implemented via a custom TemplateLoader.

Note: this is technically an API-breaking removal, but the type was unused WIP code that never provided sandboxing.

Documentation

• Clarified that pongo2 does not provide a true sandbox. BanTag and BanFilter only refuse to compile templates that reference banned names; they do not isolate Go execution, restrict filesystem access, or contain malicious templates. README, TemplateSet field comment, DefaultLoader comment, and parser error messages updated accordingly.
• Added a Security section to the README documenting that template loaders (LocalFilesystemLoader, HttpFilesystemLoader, FSLoader) do not clamp paths to a base directory and that template filenames must be treated as trusted input.

Full Changelog: https://github.com/flosch/pongo2/compare/v6.0.0...v6.1.0