Currently, when verifying our pullapprove configuration, we don't respect modifications to the set of files in a condition. e.g. It's not possible to do the following: ``` contains_any_globs(files.exclude(...), [ ``` This prevents us from having codeowner groups which match a directory, but want to filter out specific sub directories. For example, `fw-core` matches all files in the core package. We want to exclude the schematics from that glob. Usually we do this by another exclude condition. This has a *significant* downside though. It means that fw-core will not be requested if a PR changes schematic code, _and_ actual fw-core code. To support these conditions, the pullapprove verification tool is refactored, so that it no longer uses Regular expressions for parsing, but rather evaluates the code through a dynamic function. This is possible since the conditions are written in simple Python that can be run in NodeJS too (with small modifications/transformations). PR Close #36661
		
			
				
	
	
		
			100 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			TypeScript
		
	
	
	
	
	
			
		
		
	
	
			100 lines
		
	
	
		
			3.9 KiB
		
	
	
	
		
			TypeScript
		
	
	
	
	
	
/**
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 * @license
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 * Copyright Google Inc. All Rights Reserved.
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 *
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 * Use of this source code is governed by an MIT-style license that can be
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 * found in the LICENSE file at https://angular.io/license
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 */
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import {IMinimatch, Minimatch} from 'minimatch';
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/** Map that holds patterns and their corresponding Minimatch globs. */
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const patternCache = new Map<string, IMinimatch>();
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/**
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 * Context that is provided to conditions. Conditions can use various helpers
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 * that PullApprove provides. We try to mock them here. Consult the official
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 * docs for more details: https://docs.pullapprove.com/config/conditions.
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 */
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const conditionContext = {
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  'len': (value: any[]) => value.length,
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  'contains_any_globs': (files: PullApproveArray, patterns: string[]) => {
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    // Note: Do not always create globs for the same pattern again. This method
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    // could be called for each source file. Creating glob's is expensive.
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    return files.some(f => patterns.some(pattern => getOrCreateGlob(pattern).match(f)));
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  }
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};
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/**
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 * Converts a given condition to a function that accepts a set of files. The returned
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 * function can be called to check if the set of files matches the condition.
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 */
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export function convertConditionToFunction(expr: string): (files: string[]) => boolean {
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  // Creates a dynamic function with the specified expression. The first parameter will
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  // be `files` as that corresponds to the supported `files` variable that can be accessed
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  // in PullApprove condition expressions. The followed parameters correspond to other
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  // context variables provided by PullApprove for conditions.
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  const evaluateFn = new Function('files', ...Object.keys(conditionContext), `
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    return (${transformExpressionToJs(expr)});
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  `);
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  // Create a function that calls the dynamically constructed function which mimics
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  // the condition expression that is usually evaluated with Python in PullApprove.
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  return files => {
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    const result = evaluateFn(new PullApproveArray(...files), ...Object.values(conditionContext));
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    // If an array is returned, we consider the condition as active if the array is not
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    // empty. This matches PullApprove's condition evaluation that is based on Python.
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    if (Array.isArray(result)) {
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      return result.length !== 0;
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    }
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    return !!result;
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  };
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}
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/**
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 * Transforms a condition expression from PullApprove that is based on python
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 * so that it can be run inside JavaScript. Current transformations:
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 *   1. `not <..>` -> `!<..>`
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 */
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function transformExpressionToJs(expression: string): string {
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  return expression.replace(/not\s+/g, '!');
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}
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/**
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 * Superset of a native array. The superset provides methods which mimic the
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 * list data structure used in PullApprove for files in conditions.
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 */
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class PullApproveArray extends Array<string> {
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  constructor(...elements: string[]) {
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    super(...elements);
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    // Set the prototype explicitly because in ES5, the prototype is accidentally
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    // lost due to a limitation in down-leveling.
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    // https://github.com/Microsoft/TypeScript/wiki/FAQ#why-doesnt-extending-built-ins-like-error-array-and-map-work.
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    Object.setPrototypeOf(this, PullApproveArray.prototype);
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  }
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  /** Returns a new array which only includes files that match the given pattern. */
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  include(pattern: string): PullApproveArray {
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    return new PullApproveArray(...this.filter(s => getOrCreateGlob(pattern).match(s)));
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  }
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  /** Returns a new array which only includes files that did not match the given pattern. */
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  exclude(pattern: string): PullApproveArray {
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    return new PullApproveArray(...this.filter(s => !getOrCreateGlob(pattern).match(s)));
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  }
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}
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/**
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 * Gets a glob for the given pattern. The cached glob will be returned
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 * if available. Otherwise a new glob will be created and cached.
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 */
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function getOrCreateGlob(pattern: string) {
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  if (patternCache.has(pattern)) {
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    return patternCache.get(pattern)!;
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  }
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  const glob = new Minimatch(pattern, {dot: true});
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  patternCache.set(pattern, glob);
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  return glob;
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}
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