prettier: initial integration

[rootvector2]

Adds an initial OSS-Fuzz integration for Prettier, the opinionated code formatter used across a huge slice of the JS/TS/CSS/Markdown/JSON/YAML ecosystem.

The setup follows the Jazzer.js pattern used by the existing JavaScript projects in this repo (typescript, js-yaml, fast-xml-parser, etc.).

Fuzz targets

Five targets, each one wrapped around prettier.format() for a parser family, with formatting options pulled from FuzzedDataProvider:

• fuzz_format_js — babel, babel-flow, acorn, espree, meriyah, flow
• fuzz_format_ts — typescript, babel-ts
• fuzz_format_css — css, scss, less
• fuzz_format_json — json, json5, jsonc, json-stringify
• fuzz_format_md — markdown, mdx, remark

Expected parse failures (SyntaxError, "Unexpected token", "Unterminated …", etc.) are filtered out so the fuzzers only surface unexpected exceptions and crashes.

A couple of things worth flagging

• The fuzz targets live in a fuzz_targets/ subdirectory with its own tiny package.json declaring "type": "commonjs". Prettier's own package.json sets "type": "module", which would otherwise make Node load every .js file in the repo as ESM and break the CommonJS require() calls in the fuzzers.
• @jazzer.js/core is pinned to 2.1.0. The freshly released 4.0.0 ships a prebuilt native addon that needs GLIBC_2.32, which isn't available yet in base-builder-javascript (Ubuntu 20.04, glibc 2.31). Once the base image is bumped this pin can go away.
• Since Prettier v3 format() is async, the targets are written as async function and --sync is not passed to compile_javascript_fuzzer.

Test plan

• docker build of the project image succeeds
• All five fuzzers compile under base-builder-javascript
• Each fuzzer starts and runs cleanly; fuzz_format_js and fuzz_format_json produce non-trivial coverage in a short local run

[github-actions]

rootvector2 is integrating a new project:
- Main repo: https://github.com/prettier/prettier
- Criticality score: 0.67392