From db5b9d11bb88fe2aadc16c8a4db18c052dafc301 Mon Sep 17 00:00:00 2001
From: AgentEnder <craigorycoppola@gmail.com>
Date: Fri, 28 Apr 2023 13:09:02 -0400
Subject: [PATCH] fix(core): empty exclude pattern should not result in error

---
 .../nx/src/utils/find-matching-projects.spec.ts   | 12 ++++++++++++
 packages/nx/src/utils/find-matching-projects.ts   | 15 +++++++++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/packages/nx/src/utils/find-matching-projects.spec.ts b/packages/nx/src/utils/find-matching-projects.spec.ts
index 9db133323f417..41caa8e7ccb52 100644
--- a/packages/nx/src/utils/find-matching-projects.spec.ts
+++ b/packages/nx/src/utils/find-matching-projects.spec.ts
@@ -54,6 +54,18 @@ describe('findMatchingProjects', () => {
     },
   };
 
+  it('should return no projects when passed no patterns', () => {
+    expect(findMatchingProjects([], projectGraph)).toEqual([]);
+  });
+
+  it('should return no projects when passed empty string', () => {
+    expect(findMatchingProjects([''], projectGraph)).toEqual([]);
+  });
+
+  it('should not throw when a pattern is empty string', () => {
+    expect(findMatchingProjects(['', 'a'], projectGraph)).toEqual(['a']);
+  });
+
   it('should expand "*"', () => {
     expect(findMatchingProjects(['*'], projectGraph)).toEqual([
       'test-project',
diff --git a/packages/nx/src/utils/find-matching-projects.ts b/packages/nx/src/utils/find-matching-projects.ts
index 3b988e9836277..3e489401c1e2f 100644
--- a/packages/nx/src/utils/find-matching-projects.ts
+++ b/packages/nx/src/utils/find-matching-projects.ts
@@ -35,12 +35,20 @@ export function findMatchingProjects(
   patterns: string[] = [],
   projects: ProjectNodeMap
 ): string[] {
+  if (!patterns.length || patterns.filter((p) => p.length).length === 0) {
+    return []; // Short circuit if called with no patterns
+  }
+
   const projectNames = keys(projects);
 
   const selectedProjects: Set<string> = new Set();
   const excludedProjects: Set<string> = new Set();
 
   for (const stringPattern of patterns) {
+    if (!stringPattern.length) {
+      continue;
+    }
+
     const pattern = parseStringPattern(stringPattern, projects);
 
     // Handle wildcard with short-circuit, as its a common case with potentially
@@ -254,16 +262,19 @@ function isValidPatternType(type: string): type is ProjectPatternType {
 export const getMatchingStringsWithCache = (() => {
   // Map< Pattern, Map< Item, Result >>
   const minimatchCache = new Map<string, Map<string, boolean>>();
+  const regexCache = new Map<string, RegExp>();
   return (pattern: string, items: string[]) => {
     if (!minimatchCache.has(pattern)) {
       minimatchCache.set(pattern, new Map());
     }
     const patternCache = minimatchCache.get(pattern)!;
-    let matcher = null;
+    if (!regexCache.has(pattern)) {
+      regexCache.set(pattern, minimatch.makeRe(pattern));
+    }
+    const matcher = regexCache.get(pattern);
     return items.filter((item) => {
       let entry = patternCache.get(item);
       if (entry === undefined || entry === null) {
-        matcher ??= minimatch.makeRe(pattern);
         entry = item === pattern ? true : matcher.test(item);
         patternCache.set(item, entry);
       }