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perf: pass a precompiled options check to getOptions #746

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3 changes: 2 additions & 1 deletion .cspell.json
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,7 @@
"package-lock.json",
"node_modules",
"coverage",
"*.log"
"*.log",
"src/options.check.js"
]
}
1 change: 1 addition & 0 deletions .prettierignore
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Original file line number Diff line number Diff line change
Expand Up @@ -4,3 +4,4 @@
/test/fixtures
CHANGELOG.md
docs/LOADER.md
/src/options.check.js
2 changes: 2 additions & 0 deletions eslint.config.mjs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,8 @@ import { defineConfig } from "eslint/config";
import configs from "eslint-config-webpack/configs.js";

export default defineConfig([
// Generated by `schema-utils precompile`
{ ignores: ["src/options.check.js"] },
{
extends: [configs["recommended-dirty"]],
},
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4 changes: 4 additions & 0 deletions jest.config.js
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@@ -1,6 +1,10 @@
/** @type {import('ts-jest').JestConfigWithTsJest} */
module.exports = {
testTimeout: 10000,
coveragePathIgnorePatterns: [
"/node_modules/",
"<rootDir>/src/options\\.check\\.js$",
],
transform: {
"\\.[mc]?tsx?$": ["ts-jest", { rootDir: ".", esModuleInterop: true }],
"\\.[mc]?jsx?$": "babel-jest",
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28 changes: 16 additions & 12 deletions package-lock.json
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5 changes: 4 additions & 1 deletion package.json
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Expand Up @@ -32,10 +32,12 @@
"lint:prettier": "prettier --cache --list-different .",
"lint:code": "eslint --cache .",
"lint:spelling": "cspell --cache --no-must-find-files --quiet \"**/*.*\"",
"lint:schema": "schema-utils precompile --check src/options.json",
"lint": "npm-run-all -l -p \"lint:**\"",
"fix:code": "npm run lint:code -- --fix",
"fmt": "npm run lint:prettier -- --write",
"fix": "npm run fix:code && npm run fmt",
"fix:schema": "schema-utils precompile src/options.json",
"fix": "npm run fix:schema && npm run fix:code && npm run fmt",
"test:only": "cross-env NODE_ENV=test jest",
"test:watch": "npm run test:only -- --watch",
"test:coverage": "npm run test:only -- --collectCoverageFrom=\"src/**/*.js\" --coverage",
Expand Down Expand Up @@ -81,6 +83,7 @@
"prettier": "^3.3.2",
"sass": "^1.77.6",
"sass-loader": "^14.2.1",
"schema-utils": "^4.6.0",
"standard-version": "^9.3.2",
"strip-ansi": "^7.1.0",
"sugarss": "^5.0.1",
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3 changes: 2 additions & 1 deletion src/index.js
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Expand Up @@ -2,6 +2,7 @@ import path from "node:path";

import postcssPackage from "postcss/package.json";

import check from "./options.check.js";
import schema from "./options.json";
import {
exec,
Expand Down Expand Up @@ -31,7 +32,7 @@ let hasExplicitDependencyOnPostCSS = false;
* @return {callback} callback Result
*/
export default async function loader(content, sourceMap, meta) {
const options = this.getOptions(schema);
const options = this.getOptions(schema, check);

@coderabbitai coderabbitai Bot Oct 18, 2026

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🚀 Performance & Scalability | 🟡 Minor | ⚡ Quick win

🔎 Supported by static analysis

🏁 Script executed:

python3 - <<'PY'
import io
import json
import re
import tarfile
import urllib.request

def get(url):
    req = urllib.request.Request(url, headers={"User-Agent": "review-inspection"})
    with urllib.request.urlopen(req, timeout=30) as r:
        return r.read()

meta = json.loads(get("https://registry.npmjs.org/webpack"))
versions = [
    v for v in meta["versions"]
    if v.startswith("5.") and re.fullmatch(r"5\.\d+\.\d+", v)
]
versions.sort(key=lambda v: tuple(map(int, v.split("."))))
print(f"published webpack 5.x releases: {len(versions)}")
contradictions = []
missing = []
signatures = {}
for version in versions:
    info = meta["versions"][version]
    tarball = info["dist"]["tarball"]
    try:
        data = get(tarball)
        with tarfile.open(fileobj=io.BytesIO(data), mode="r:gz") as tf:
            candidates = [
                n for n in tf.getnames()
                if n.endswith("/lib/NormalModule.js") or n.endswith("/lib/module/NormalModule.js")
            ]
            if not candidates:
                missing.append((version, "NormalModule.js not found"))
                continue
            name = candidates[0]
            text = tf.extractfile(name).read().decode("utf-8", "replace")
            pos = text.find("getOptions")
            excerpt = text[pos:pos+500] if pos >= 0 else "getOptions not found"
            signatures[version] = " ".join(excerpt.split())
            # Look for a parameter list that includes a second argument at the definition.
            definitions = re.findall(r"getOptions\s*:\s*\(([^)]*)\)", text)
            if not definitions:
                definitions = re.findall(r"getOptions\s*:\s*([A-Za-z_$][\\w$]*)", text)
            if any("," in d for d in definitions):
                contradictions.append((version, definitions, name))
    except Exception as e:
        missing.append((version, type(e).__name__ + ": " + str(e)))

print("releases with a getOptions definition containing a second parameter:", len(contradictions))
for row in contradictions:
    print("CONTRADICTS", row)
print("uninspected releases:", len(missing))
for row in missing[:20]:
    print("MISSING", row)
for version in (versions[:3] + versions[len(versions)//2:len(versions)//2+1] + versions[-3:]):
    print("SIGNATURE", version, signatures.get(version, "<unavailable>"))

print("\nREPOSITORY SOURCES")
for path, start, end in (("src/index.js", 1, 55), ("package.json", 88, 101)):
    print(f"--- {path}:{start}-{end}")
    lines = open(path, encoding="utf-8").read().splitlines()
    for n in range(start, min(end, len(lines)) + 1):
        print(f"{n}: {lines[n-1]}")
PY

Repository: webpack/postcss-loader

Length of output: 496

🏁 Script executed:

python3 - <<'PY'
import concurrent.futures
import io
import json
import re
import tarfile
import urllib.request

def get(url):
    req = urllib.request.Request(url, headers={"User-Agent": "review-inspection"})
    with urllib.request.urlopen(req, timeout=15) as r:
        return r.read()

meta = json.loads(get("https://registry.npmjs.org/webpack"))
versions = sorted(
    [v for v in meta["versions"] if re.fullmatch(r"5\.\d+\.\d+", v)],
    key=lambda v: tuple(map(int, v.split("."))),
)

def inspect(version):
    try:
        data = get(meta["versions"][version]["dist"]["tarball"])
        with tarfile.open(fileobj=io.BytesIO(data), mode="r:gz") as tf:
            names = [n for n in tf.getnames() if n.endswith("/lib/NormalModule.js") or n.endswith("/lib/module/NormalModule.js")]
            if not names:
                return version, "missing source", ""
            text = tf.extractfile(names[0]).read().decode("utf-8", "replace")
            matches = re.findall(r"getOptions\s*:\s*\(([^)]*)\)", text)
            if not matches:
                matches = re.findall(r"getOptions\s*:\s*([A-Za-z_$][A-Za-z0-9_$]*)", text)
            return version, "second parameter" if any("," in m for m in matches) else "schema only", " | ".join(matches)
    except Exception as exc:
        return version, "error", type(exc).__name__ + ": " + str(exc)

results = []
with concurrent.futures.ThreadPoolExecutor(max_workers=24) as pool:
    for result in pool.map(inspect, versions):
        results.append(result)

print("release_count", len(versions))
for version, status, detail in results:
    if status != "schema only":
        print("EXCEPTION", version, status, detail)
print("schema_only_count", sum(status == "schema only" for _, status, _ in results))
print("missing_or_error_count", sum(status != "schema only" for _, status, _ in results))
for version in versions[:2] + versions[-2:]:
    row = next(r for r in results if r[0] == version)
    print("sample", row)

print("REPOSITORY")
for path, start, end in (("src/index.js", 30, 38), ("package.json", 92, 99)):
    print(f"--- {path}:{start}-{end}")
    lines = open(path, encoding="utf-8").read().splitlines()
    for n in range(start, end + 1):
        print(f"{n}: {lines[n-1]}")
PY

Repository: webpack/postcss-loader

Length of output: 1090

🏁 Script executed:

python3 - <<'PY'
import concurrent.futures
import io
import json
import re
import tarfile
import urllib.request

def get(url):
    req = urllib.request.Request(url, headers={"User-Agent": "review-inspection"})
    with urllib.request.urlopen(req, timeout=15) as r:
        return r.read()

meta = json.loads(get("https://registry.npmjs.org/webpack"))
versions = sorted(
    [v for v in meta["versions"] if re.fullmatch(r"5\.\d+\.\d+", v)],
    key=lambda v: tuple(map(int, v.split("."))),
)

def body_after_get_options(text):
    pos = text.find("getOptions")
    if pos < 0:
        return None
    brace = text.find("{", pos)
    if brace < 0:
        return None
    depth = 0
    quote = None
    escaped = False
    for i in range(brace, len(text)):
        c = text[i]
        if quote:
            if escaped:
                escaped = False
            elif c == "\\":
                escaped = True
            elif c == quote:
                quote = None
        elif c in "'\"`":
            quote = c
        elif c == "{":
            depth += 1
        elif c == "}":
            depth -= 1
            if depth == 0:
                return text[brace:i+1]
    return None

def inspect(version):
    try:
        data = get(meta["versions"][version]["dist"]["tarball"])
        with tarfile.open(fileobj=io.BytesIO(data), mode="r:gz") as tf:
            names = [n for n in tf.getnames() if n.endswith("/lib/NormalModule.js") or n.endswith("/lib/module/NormalModule.js")]
            text = tf.extractfile(names[0]).read().decode("utf-8", "replace")
            body = body_after_get_options(text)
            if body is None:
                return version, "no-body", ""
            suspicious = []
            if re.search(r"\barguments\s*\[\s*1\s*\]", body):
                suspicious.append("arguments[1]")
            if re.search(r"\b(check|checker|compiled)\b", body, re.I):
                suspicious.append("checker-term")
            if not re.search(r"\bvalidate\b|\bschema-utils\b", body):
                suspicious.append("no-validation-token")
            return version, "ok" if not suspicious else " ".join(suspicious), " ".join(body[:220].split())
    except Exception as exc:
        return version, "error", type(exc).__name__ + ": " + str(exc)

with concurrent.futures.ThreadPoolExecutor(max_workers=24) as pool:
    results = list(pool.map(inspect, versions))

print("release_count", len(results))
for row in results:
    if row[1] != "ok":
        print("EXCEPTION", row)
print("clean_getOptions_bodies", sum(status == "ok" for _, status, _ in results))
print("exception_count", sum(status != "ok" for _, status, _ in results))
PY

Repository: webpack/postcss-loader

Length of output: 33118

The declared webpack range does not provide the claimed optimization.

All 221 published stable webpack 5.x releases allowed by ^5.0.0 define getOptions with only the schema parameter. No release consumes the second argument as a precompiled checker. Webpack therefore continues its normal schema validation, so this change does not improve performance for webpack consumers.

Remove or defer the checker-specific changes until webpack releases support for this argument.

@alexander-akait alexander-akait Oct 18, 2026

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Intended: it lands ahead of webpack/webpack#22745. Released webpack ignores the second argument and validates as before, so nothing changes for current users. Once #22745 ships, the fast path applies without another postcss-loader release. A maintainer can also hold this until then.

Generated by Claude Code

const callback = this.async();
const configOption =
typeof options.postcssOptions === "undefined" ||
Expand Down
7 changes: 7 additions & 0 deletions src/options.check.js
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23 changes: 23 additions & 0 deletions test/validate-options.test.js
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Original file line number Diff line number Diff line change
@@ -1,7 +1,26 @@
import path from "node:path";

import { validate } from "schema-utils";

import check from "../src/options.check";
import schema from "../src/options.json";

import { compile, getCompiler } from "./helpers/index";

/**
* @param {object} options loader options
* @returns {boolean} whether the schema accepts them
*/
function isValid(options) {
try {
validate(schema, options);

return true;
} catch {
return false;
}
}

describe("validate options", () => {
const tests = {
execute: {
Expand Down Expand Up @@ -70,6 +89,10 @@ describe("validate options", () => {
it(`should ${
type === "success" ? "successfully validate" : "throw an error on"
} the "${key}" option with "${stringifyValue(value)}" value`, async () => {
// webpack trusts a check that passes and skips the schema, so the two
// must agree on every value
expect(check({ [key]: value })).toBe(isValid({ [key]: value }));

let compiler;

if (
Expand Down
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