Remove Python 2 support

Author: artnc

Dockerfile

@@ -46,18 +46,9 @@ apk add --no-cache \
   python3
 pip3 install --break-system-packages \
   autoflake==1.7.8 \
-  isort==5.13.2 \
   ruff==0.15.10 \
   'PyYAML>=6.0'
 
-# Install Python dependencies
-python3 -m venv /black21-venv
-source /black21-venv/bin/activate
-pip3 install black==21.12b0 click==8.0.4
-deactivate
-echo 'source /black21-venv/bin/activate && black "$@"' > /usr/bin/black21
-chmod +x /usr/bin/black21
-
 # Install Node dependencies
 npm install -g \
   @eslint/compat@2.0.5 \
@@ -113,15 +104,6 @@ find /usr/local/lib/node_modules -type d \
 apk del .build-deps
 rm -rf \
   /bin/coursier \
-  /black21-venv/bin/Activate.ps1 \
-  /black21-venv/bin/activate.csh \
-  /black21-venv/bin/activate.fish \
-  /black21-venv/bin/pip \
-  /black21-venv/bin/pip3 \
-  /black21-venv/bin/pip3.12 \
-  /black21-venv/lib/python3.12/site-packages/pip \
-  /black21-venv/lib/python3.12/site-packages/pkg_resources \
-  /black21-venv/lib/python3.12/site-packages/setuptools \
   /root/.cache \
   /root/.npm \
   /usr/bin/lto-dump \

README.md

@@ -8,10 +8,8 @@ The main hook that runs several code formatters in parallel:
 
 - [Prettier](https://github.com/prettier/prettier) v3.8.3 for CSS, HTML, JS, JSX, Markdown, Sass, TypeScript, XML, YAML
 - [ESLint](https://eslint.org/) v10.2.0 for JS, TypeScript
-- [Ruff](https://docs.astral.sh/ruff/) v0.15.10 for Python 3
-- [Black](https://github.com/psf/black) v21.12b0 for Python 2
-- [autoflake](https://github.com/myint/autoflake) v1.7.8 for Python <!-- TODO: Upgrade to v2+, restrict to Python 2, and reenable Ruff rule F401 once our Python 3 repos that were converted from Python 2 no longer use type hint comments: https://github.com/PyCQA/autoflake/issues/222#issuecomment-1419089254 -->
-- [isort](https://github.com/PyCQA/isort) v5.13.2 for Python 2
+- [Ruff](https://docs.astral.sh/ruff/) v0.15.10 for Python
+- [autoflake](https://github.com/myint/autoflake) v1.7.8 for Python <!-- TODO: Remove in favor of Ruff rule F401 once our Python 3 repos that were converted from Python 2 no longer use type hint comments: https://github.com/PyCQA/autoflake/issues/222#issuecomment-1419089254 -->
 - [google-java-format](https://github.com/google/google-java-format) v1.35.0 for Java
 - [ktfmt](https://github.com/facebookincubator/ktfmt) v0.62 for Kotlin
 - [gradle-dependencies-sorter](https://github.com/square/gradle-dependencies-sorter) v0.16 for Gradle Kotlin
@@ -25,7 +23,7 @@ The main hook that runs several code formatters in parallel:
 - [Taplo](https://taplo.tamasfe.dev/) v0.10.0 for TOML
 - Custom regex transformations (basically [sed](https://en.wikipedia.org/wiki/Sed)), for example:
   - Trimming trailing whitespace and newlines
-  - Removing unnecessary `coding` pragmas and `object` base classes in Python 3
+  - Removing unnecessary `coding` pragmas and `object` base classes in Python
   - Replacing empty Python collections like `list()` with literal equivalents
   - Replacing empty Kotlin collections like `arrayOf()` with `empty` equivalents
 
@@ -63,7 +61,6 @@ Repo maintainers can declare these hooks in `.pre-commit-config.yaml`:
     # Code formatting hook
     - id: duolingo
       args: # Optional
-        - --python-version=2 # Defaults to Python 3
         - --scala-version=3 # Defaults to Scala 2.12
     # Sync AI rules hook (for repos with Cursor AI rules)
     - id: sync-ai-rules

entry.ts

@@ -79,13 +79,11 @@ const transformFile = (path: string, transform: (before: string) => string) =>
 
 const enum HookName {
   Autoflake = "autoflake",
-  Black = "Black",
   ClangFormat = "ClangFormat",
   EsLint = "ESLint",
   Gofmt = "gofmt",
   GoogleJavaFormat = "google-java-format",
   GradleDependenciesSorter = "gradle-dependencies-sorter",
-  Isort = "isort",
   Ktfmt = "ktfmt",
   PackerFmt = "packer fmt",
   Prettier = "Prettier",
@@ -142,28 +140,6 @@ const HOOKS: Record<HookName, Hook> = {
     include: /\.py$/,
     runAfter: [HookName.Sed],
   },
-  [HookName.Black]: {
-    action: async (sources, args) =>
-      args["python-version"]?.startsWith("2") &&
-      run(
-        // Black 21.x was the last major version with Python 2 support. It also
-        // had a bug that requires pinning click==8.0.4. Both packages should
-        // be removed once we drop Python 2 support.
-        // https://github.com/psf/black/issues/2964
-        "black21",
-        "--fast",
-        "--target-version",
-        "py27",
-        "--config",
-        EMPTY_FILE,
-        "--line-length",
-        "100",
-        "--quiet",
-        ...sources,
-      ),
-    include: /\.py$/,
-    runAfter: [HookName.Isort],
-  },
   [HookName.ClangFormat]: {
     action: sources =>
       run(
@@ -213,16 +189,6 @@ const HOOKS: Record<HookName, Hook> = {
     include: /build\.gradle\.kts$/,
     runAfter: [HookName.Sed],
   },
-  [HookName.Isort]: {
-    // isort's automatic config file detection is broken
-    // https://github.com/PyCQA/isort/issues/1907
-    // https://github.com/samueljsb/qaz/pull/104
-    action: (sources, args) =>
-      args["python-version"]?.startsWith("2") &&
-      run("isort", "--settings", "/.editorconfig", ...sources),
-    include: /\.py$/,
-    runAfter: [HookName.Autoflake],
-  },
   [HookName.Ktfmt]: {
     action: async sources => {
       /** Try to avoid ktfmt OOMs presumably caused by too many input files */
@@ -287,10 +253,7 @@ const HOOKS: Record<HookName, Hook> = {
     runAfter: [HookName.Sed],
   },
   [HookName.Ruff]: {
-    action: async (sources, args) => {
-      if (args["python-version"]?.startsWith("2")) {
-        return;
-      }
+    action: async sources => {
       // Sometimes Ruff requires multiple passes, which is ok since it's fast
       for (let i = 0; i < 2; ++i) {
         await run("ruff", "check", "--config", "/ruff.toml", ...sources);
@@ -329,7 +292,7 @@ const HOOKS: Record<HookName, Hook> = {
   // to ever actually be needed. At Duolingo, we determine the latter criterion
   // empirically by seeing how many existing violations our codebase contains
   [HookName.Sed]: {
-    action: (sources, args) =>
+    action: sources =>
       Promise.all(
         sources.map(source =>
           transformFile(source, data => {
@@ -369,14 +332,11 @@ const HOOKS: Record<HookName, Hook> = {
                 "",
               );
 
-              // Transform Python 3
-              if (!args["python-version"]?.startsWith("2")) {
-                // Remove unnecessary encoding declarations
-                data = data.replace(/^# -\*- coding: utf-?8.*?\n/gim, "");
+              // Remove unnecessary encoding declarations
+              data = data.replace(/^# -\*- coding: utf-?8.*?\n/gim, "");
 
-                // Remove unnecessary base class declarations
-                data = data.replace(/(?<=^ *class \S+?)\(object\)(?=:)/gm, "");
-              }
+              // Remove unnecessary base class declarations
+              data = data.replace(/(?<=^ *class \S+?)\(object\)(?=:)/gm, "");
             }
 
             return data;
@@ -505,8 +465,6 @@ const prefixLines = (() => {
       /^\s*$/,
       // ktfmt spams this for every file that has no violations
       /\bDone formatting .+\.kts?$/,
-      // Black 21.12b0 spams this when running on Python 2 source code
-      /\bDEPRECATION: Python 2 support\b/,
     ]
       .map(regex => regex.source)
       .join("|"),
@@ -536,6 +494,12 @@ const prefixLines = (() => {
     }
   }
 
+  // Python 2 is no longer supported
+  if (args["python-version"]?.startsWith("2")) {
+    console.error("This hook no longer supports Python 2.");
+    process.exit(1);
+  }
+
   // Augment hook definitions to make them lockable
   interface LockableHook extends Hook {
     /** Upon resolution, indicates that this hook has completed */