semgrep VS ast-grep

Semgrep OSS Owner/Maintainer: Semgrep Age: First release on GitHub on February 6th, 2020 License: GNU Lesser General Public License v2.1

Semgrep - https://semgrep.dev

For the SAST stage, I used SonarQube tool. SonarQube is an open-source platform developed by SonarSource for continuous inspection of code quality to perform automatic reviews with static analysis of code to detect bugs and code smells on more than 30 programming languages. I preferred SonarQube instead of other SAST tools because it has a detailed documentation and plugins about integration with Jenkins and SonarQube works with Java projects pretty well. Of course you can similar multi-language-supported tools such as Semgrep or language-specific tools such as Bandit.

> Not sure I understand your point.

The problem is using Treesitter (for syntax highlighting and "semantic movements") and an LSP at the same time. So if your language has a LSP, using Treesitter additionally is redundant at best and introduces inconcistency at worst.

I'm not talking about using Treesitter as the parser for the LSP.

> Most popular languages have language-specific tools

I'd say even less popular langauges like Coq^H^H^HRocq, Lean 4, Koka, Idris, Unison, ... have their "own" tools, I do not know of a language that uses a Treesitter parser in its LSP, but I do know about tools like https://semgrep.dev/ (written in OCaml) and Github's code search which use Treesitter.

Well, when I seach for "semgrep", I get a very nice corporate landing page with a "Book Demo" button. Which is a level of hassle that just isn't worth it for smaller teams, because "Book Demo" usually means "We're going to try to do a dance to see how much money we can extract from you." Which smaller teams may only want to do for a handful of key tools.

(4 years ago, I was more willing to put up with enterprise licensing. But in the last two years, I've seen way too many enterprise vendors try to squeeze every penny they can get from existing clients. An enterprise sales process now often means "Expect 30% annual price hikes once you're in too deep to back out.")

There's also an open source "semgrep" project here: https://github.com/semgrep/semgrep. But this seems to be basically a vulernability scanner, going by the README.

Whereas AST-grep seems to focus heavily on things like:

1. One-off searching: "Search my tree for this pattern."

2. Refactoring: "Replace this pattern with this other pattern."

AST-grep also includes a vulnerability scanning mode like semgrep.

It's possible that semgrep also has nice support for (1) and (2), but it isn't clearly visible on their corporate landing page or the first open source README I found.

7. Semgrep

It's unclear what the superpowers would be? Video doesn't show anything I can't do with an IDE or decent code editor, and there I also have refactoring tools, metadata like indicators for usages that can be used for navigating and so on.

Reminds me of UML-like diagrams over relational databases, except that it's generated one piece at a time. In practice I generate diagrams showing cyclomatic complexity much more often, and for code exploration outside the IDE I'd use ast-grep.

https://ast-grep.github.io/

This article illustrates the usage of ast-grep, a tool designed to locate and substitute patterns in your codebase, towards easing your migration to React 19.

This looks great, thanks for building and sharing it.

Interested folks may also want to check out ast-grep:

https://github.com/ast-grep/ast-grep

ast-grep is a command-line tool that lets you search and transform code written in many programming languages using abstract syntax trees (ASTs). ASTs are data structures that capture the syntactic and semantic structure of source code. With ast-grep, you can write patterns as if you are writing ordinary code, and it will match all code that has the same syntactical structure. And if you need more power, you can use YAML, a rule system that allows you to write more sophisticated linting rules or code modifications.

I really like this - it means the tool is available to people with familiarity of any of those four distribution mechanisms.

You can also download pre-built binaries from their releases page: https://github.com/ast-grep/ast-grep/releases/tag/0.14.2

On top of that, they offer API bindings for it in three different languages:

- Rust (not yet stable): https://docs.rs/ast-grep-core/latest/ast_grep_core/

- JavaScript/TypeScript: https://ast-grep.github.io/guide/api-usage/js-api.html

- Python: https://ast-grep.github.io/guide/api-usage/py-api.html

It's rare to see a tool/library offer this depth of language support out of the box.