deps: remove promise-inflight (#223)

The use of promise-inflight was originally intended to prevent duplicate
concurrent git ls-remote calls. However, this scenario is rare, and the
performance impact of duplicate calls is minimal. The existing LRU cache
already prevents redundant requests over time.

Removing promise-inflight simplifies the code and removes a dependency
often cited by security linters. This does mean duplicate inflight
requests are now possible, but the expected impact is negligible. Should
we want to make sure they don't happen, we could inline a solution
fairly easily

lib/revs.js

@@ -1,14 +1,12 @@
-const pinflight = require('promise-inflight')
 const spawn = require('./spawn.js')
 const { LRUCache } = require('lru-cache')
+const linesToRevs = require('./lines-to-revs.js')
 
 const revsCache = new LRUCache({
   max: 100,
   ttl: 5 * 60 * 1000,
 })
 
-const linesToRevs = require('./lines-to-revs.js')
-
 module.exports = async (repo, opts = {}) => {
   if (!opts.noGitRevCache) {
     const cached = revsCache.get(repo)
@@ -17,12 +15,8 @@ module.exports = async (repo, opts = {}) => {
     }
   }
 
-  return pinflight(`ls-remote:${repo}`, () =>
-    spawn(['ls-remote', repo], opts)
-      .then(({ stdout }) => linesToRevs(stdout.trim().split('\n')))
-      .then(revs => {
-        revsCache.set(repo, revs)
-        return revs
-      })
-  )
+  const { stdout } = await spawn(['ls-remote', repo], opts)
+  const revs = linesToRevs(stdout.trim().split('\n'))
+  revsCache.set(repo, revs)
+  return revs
 }

test/revs.js

@@ -120,3 +120,28 @@ t.test('check the revs', async t => {
   Object.keys(r.shas).forEach(sha => r.shas[sha].forEach(ref =>
     t.equal(r.refs[ref].sha, sha, `shas list is consistent ${ref}`)))
 })
+
+t.test('cache prevents repeated git ls-remote calls', async t => {
+  let callCount = 0
+  const originalSpawn = require('../lib/spawn.js')
+
+  // Mock `spawn` to track calls
+  require.cache[require.resolve('../lib/spawn.js')].exports = (...args) => {
+    callCount++
+    return originalSpawn(...args)
+  }
+
+  // Force reloading revs.js after modifying spawn
+  delete require.cache[require.resolve('../lib/revs.js')]
+  const revsModule = require('../lib/revs.js')
+
+  await revsModule(repo) // First call should hit `git ls-remote`
+  await revsModule(repo) // Second call should use cache
+
+  t.equal(callCount, 1, 'git ls-remote should be called only once due to caching')
+
+  // Restore original spawn.js
+  t.teardown(() => {
+    require.cache[require.resolve('../lib/spawn.js')].exports = originalSpawn
+  })
+})