Merge pull request #1903 from DaveLak/fuzzing-integration-follow-ups

Fuzzer Migration Follow-ups

Author: Byron

fuzzing/README.md

@@ -6,8 +6,8 @@ This directory contains files related to GitPython's suite of fuzz tests that ar
 infrastructure provided by [OSS-Fuzz][oss-fuzz-repo]. This document aims to provide necessary information for working
 with fuzzing in GitPython.
 
-The latest details regarding OSS-Fuzz test status, including build logs and coverage reports, is made available
-at [this link](https://introspector.oss-fuzz.com/project-profile?project=gitpython).
+The latest details regarding OSS-Fuzz test status, including build logs and coverage reports, is available
+on [the Open Source Fuzzing Introspection website](https://introspector.oss-fuzz.com/project-profile?project=gitpython).
 
 ## How to Contribute
 
@@ -129,47 +129,45 @@ This approach uses Docker images provided by OSS-Fuzz for building and running f
 comprehensive features but requires a local clone of the OSS-Fuzz repository and sufficient disk space for Docker
 containers.
 
-#### Preparation
-
-Set environment variables to simplify command usage:
-
-```shell
-# $SANITIZER can be either 'address' or 'undefined':
-export SANITIZER=address
-# specify the fuzz target without the .py extension:
-export FUZZ_TARGET=fuzz_config
-```
-
-#### Build and Run
+#### Build the Execution Environment
 
 Clone the OSS-Fuzz repository and prepare the Docker environment:
 
 ```shell
 git clone --depth 1 https://github.com/google/oss-fuzz.git oss-fuzz
 cd oss-fuzz
 python infra/helper.py build_image gitpython
-python infra/helper.py build_fuzzers --sanitizer $SANITIZER gitpython
+python infra/helper.py build_fuzzers --sanitizer address gitpython
 ```
 
 > [!TIP]
-> The `build_fuzzers` command above accepts a local file path pointing to your gitpython repository clone as the last
+> The `build_fuzzers` command above accepts a local file path pointing to your GitPython repository clone as the last
 > argument.
 > This makes it easy to build fuzz targets you are developing locally in this repository without changing anything in
 > the OSS-Fuzz repo!
 > For example, if you have cloned this repository (or a fork of it) into: `~/code/GitPython`
 > Then running this command would build new or modified fuzz targets using the `~/code/GitPython/fuzzing/fuzz-targets`
 > directory:
 > ```shell
-> python infra/helper.py build_fuzzers --sanitizer $SANITIZER gitpython ~/code/GitPython
+> python infra/helper.py build_fuzzers --sanitizer address gitpython ~/code/GitPython
 > ```
 
-
 Verify the build of your fuzzers with the optional `check_build` command:
 
 ```shell
 python infra/helper.py check_build gitpython
 ```
 
+#### Run a Fuzz Target
+
+Setting an environment variable for the fuzz target argument of the execution command makes it easier to quickly select
+a different target between runs:
+
+```shell
+# specify the fuzz target without the .py extension:
+export FUZZ_TARGET=fuzz_config
+```
+
 Execute the desired fuzz target:
 
 ```shell

fuzzing/fuzz-targets/fuzz_config.py

@@ -1,4 +1,3 @@
-#!/usr/bin/python3
 # Copyright 2023 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");

fuzzing/fuzz-targets/fuzz_tree.py

@@ -1,4 +1,3 @@
-#!/usr/bin/python3
 # Copyright 2023 Google LLC
 #
 # Licensed under the Apache License, Version 2.0 (the "License");

fuzzing/oss-fuzz-scripts/build.sh

@@ -1,10 +1,10 @@
-#!/usr/bin/env bash
+# shellcheck shell=bash
 
 set -euo pipefail
 
 python3 -m pip install .
 
-# Directory to look in for dictionaries, options files, and seed corpa:
+# Directory to look in for dictionaries, options files, and seed corpora:
 SEED_DATA_DIR="$SRC/seed_data"
 
 find "$SEED_DATA_DIR" \( -name '*_seed_corpus.zip' -o -name '*.options' -o -name '*.dict' \) \
@@ -13,7 +13,7 @@ find "$SEED_DATA_DIR" \( -name '*_seed_corpus.zip' -o -name '*.options' -o -name
   -exec cp {} "$OUT" \;
 
 # Build fuzzers in $OUT.
-find "$SRC/gitpython/fuzzing" -name 'fuzz_*.py' -print0 | while IFS= read -r -d $'\0' fuzz_harness; do
+find "$SRC/gitpython/fuzzing" -name 'fuzz_*.py' -print0 | while IFS= read -r -d '' fuzz_harness; do
   compile_python_fuzzer "$fuzz_harness"
 
   common_base_dictionary_filename="$SEED_DATA_DIR/__base.dict"
@@ -27,7 +27,7 @@ find "$SRC/gitpython/fuzzing" -name 'fuzz_*.py' -print0 | while IFS= read -r -d
       # If a dictionary file for this fuzzer already exists and is not empty,
       # we append a new line to the end of it before appending any new entries.
       #
-      # libfuzzer will happily ignore multiple empty lines in a dictionary but crash
+      # LibFuzzer will happily ignore multiple empty lines in a dictionary but fail with an error
       # if any single line has incorrect syntax (e.g., if we accidentally add two entries to the same line.)
       # See docs for valid syntax: https://llvm.org/docs/LibFuzzer.html#id32
       echo >>"$output_file"

fuzzing/oss-fuzz-scripts/container-environment-bootstrap.sh

@@ -34,23 +34,24 @@ download_and_concatenate_common_dictionaries() {
   done
 }
 
-fetch_seed_corpra() {
+fetch_seed_corpora() {
   # Seed corpus zip files are hosted in a separate repository to avoid additional bloat in this repo.
   git clone --depth 1 https://github.com/gitpython-developers/qa-assets.git qa-assets &&
     rsync -avc qa-assets/gitpython/corpra/ "$SEED_DATA_DIR/" &&
-    rm -rf qa-assets; # Clean up the cloned repo to keep the Docker image as slim as possible.
+    rm -rf qa-assets # Clean up the cloned repo to keep the Docker image as slim as possible.
 }
 
 ########################
 # Main execution logic #
 ########################
 
-fetch_seed_corpra;
+fetch_seed_corpora
 
 download_and_concatenate_common_dictionaries "$SEED_DATA_DIR/__base.dict" \
   "https://raw.githubusercontent.com/google/fuzzing/master/dictionaries/utf8.dict" \
-  "https://raw.githubusercontent.com/google/fuzzing/master/dictionaries/url.dict";
+  "https://raw.githubusercontent.com/google/fuzzing/master/dictionaries/url.dict"
 
 # The OSS-Fuzz base image has outdated dependencies by default so we upgrade them below.
-python3 -m pip install --upgrade pip;
-python3 -m pip install 'setuptools~=69.0' 'pyinstaller~=6.0'; # Uses the latest versions know to work at the time of this commit.
+python3 -m pip install --upgrade pip
+# Upgrade to the latest versions known to work at the time the below changes were introduced:
+python3 -m pip install 'setuptools~=69.0' 'pyinstaller~=6.0'