Update usage instructions and lockfile for py-fuzzer script (#20940)

Author: AlexWaygood

.github/workflows/ci.yaml

@@ -498,9 +498,10 @@ jobs:
           chmod +x "${DOWNLOAD_PATH}/ruff"
 
           (
-            uvx \
+            uv run \
             --python="${PYTHON_VERSION}" \
-            --from=./python/py-fuzzer \
+            --project=./python/py-fuzzer \
+            --locked \
             fuzz \
             --test-executable="${DOWNLOAD_PATH}/ruff" \
             --bin=ruff \
@@ -694,9 +695,10 @@ jobs:
           chmod +x "${PWD}/ty" "${NEW_TY}/ty"
 
           (
-            uvx \
+            uv run \
             --python="${PYTHON_VERSION}" \
-            --from=./python/py-fuzzer \
+            --project=./python/py-fuzzer \
+            --locked \
             fuzz \
             --test-executable="${NEW_TY}/ty" \
             --baseline-executable="${PWD}/ty" \

.github/workflows/daily_fuzz.yaml

@@ -48,9 +48,10 @@ jobs:
         run: |
           # shellcheck disable=SC2046
           (
-            uvx \
-            --python=3.12 \
-            --from=./python/py-fuzzer \
+            uv run \
+            --python=3.13 \
+            --project=./python/py-fuzzer \
+            --locked \
             fuzz \
             --test-executable=target/debug/ruff \
             --bin=ruff \

crates/ruff_python_parser/CONTRIBUTING.md

@@ -62,7 +62,7 @@ To run the fuzzer, execute the following command
 (requires [`uv`](https://github.com/astral-sh/uv) to be installed):
 
 ```sh
-uvx --from ./python/py-fuzzer fuzz
+uv run --project=./python/py-fuzzer fuzz
 ```
 
 Refer to the [py-fuzzer](https://github.com/astral-sh/ruff/blob/main/python/py-fuzzer/fuzz.py)

python/py-fuzzer/README.md

@@ -3,6 +3,6 @@
 A fuzzer script to run Ruff executables on randomly generated
 (but syntactically valid) Python source-code files.
 
-Run `uvx --from ./python/py-fuzzer fuzz -h` from the repository root
+Run `uv run --project=./python/py-fuzzer fuzz -h` from the repository root
 for more information and example invocations
 (requires [`uv`](https://github.com/astral-sh/uv) to be installed).

python/py-fuzzer/fuzz.py

@@ -4,24 +4,21 @@
 
 This script can be installed into a virtual environment using
 `uv pip install -e ./python/py-fuzzer` from the Ruff repository root,
-or can be run using `uvx --from ./python/py-fuzzer fuzz`
+or can be run using `uv run --project=./python/py-fuzzer fuzz`
 (in which case the virtual environment does not need to be activated).
+Note that using `uv run --project` rather than `uvx --from` means that
+uv will respect the script's lockfile.
 
 Example invocations of the script using `uv`:
 - Run the fuzzer on Ruff's parser using seeds 0, 1, 2, 78 and 93 to generate the code:
-  `uvx --from ./python/py-fuzzer fuzz --bin ruff 0-2 78 93`
+  `uv run --project=./python/py-fuzzer fuzz --bin ruff 0-2 78 93`
 - Run the fuzzer concurrently using seeds in range 0-10 inclusive,
   but only reporting bugs that are new on your branch:
-  `uvx --from ./python/py-fuzzer fuzz --bin ruff 0-10 --only-new-bugs`
+  `uv run --project=./python/py-fuzzer fuzz --bin ruff 0-10 --only-new-bugs`
 - Run the fuzzer concurrently on 10,000 different Python source-code files,
   using a random selection of seeds, and only print a summary at the end
   (the `shuf` command is Unix-specific):
-  `uvx --from ./python/py-fuzzer fuzz --bin ruff $(shuf -i 0-1000000 -n 10000) --quiet
-
-If you make local modifications to this script, you'll need to run the above
-with `--reinstall` to get your changes reflected in the uv-cached installed
-package. Alternatively, if iterating quickly on changes, you can add
-`--with-editable ./python/py-fuzzer`.
+  `uv run --project=./python/py-fuzzer fuzz --bin ruff $(shuf -i 0-1000000 -n 10000) --quiet
 """
 
 from __future__ import annotations