chore: publish to the latest tag correctly when releasing old versions (#15515) (#15528)

Manual backport of #15274 to <= 3-0-x

script/publish-to-npm.js

@@ -5,6 +5,7 @@ const childProcess = require('child_process')
 const GitHubApi = require('github')
 const {GitProcess} = require('dugite')
 const request = require('request')
+const semver = require('semver')
 const rootPackageJson = require('../package.json')
 
 if (!process.env.ELECTRON_NPM_OTP) {
@@ -109,15 +110,26 @@ new Promise((resolve, reject) => {
   })
 })
 .then(async (release) => {
+  const currentBranch = await getCurrentBranch()
+
   if (release.tag_name.indexOf('nightly') > 0) {
-    const currentBranch = await getCurrentBranch()
     if (currentBranch === 'master') {
       npmTag = 'nightly'
     } else {
       npmTag = `nightly-${currentBranch}`
     }
   } else {
-    npmTag = release.prerelease ? 'beta' : 'latest'
+    if (currentBranch === 'master') {
+      // This should never happen, master releases should be nightly releases
+      // this is here just-in-case
+      npmTag = 'master'
+    } else if (!release.prerelease) {
+      // Tag the release with a `2-0-x` style tag
+      npmTag = currentBranch
+    } else {
+      // Tag the release with a `beta-3-0-x` style tag
+      npmTag = `beta-${currentBranch}`
+    }
   }
 })
 .then(() => childProcess.execSync('npm pack', { cwd: tempDir }))
@@ -133,6 +145,19 @@ new Promise((resolve, reject) => {
   })
 })
 .then((tarballPath) => childProcess.execSync(`npm publish ${tarballPath} --tag ${npmTag} --otp=${process.env.ELECTRON_NPM_OTP}`))
+.then(() => {
+  const currentTags = JSON.parse(childProcess.execSync('npm show electron dist-tags --json').toString())
+  const localVersion = rootPackageJson.version
+  const parsedLocalVersion = semver.parse(localVersion)
+  if (parsedLocalVersion.prerelease.length === 0 &&
+        semver.gt(localVersion, currentTags.latest)) {
+    childProcess.execSync(`npm dist-tag add electron@${localVersion} latest --otp=${process.env.ELECTRON_NPM_OTP}`)
+  }
+  if (parsedLocalVersion.prerelease[0] === 'beta' &&
+        semver.gt(localVersion, currentTags.beta)) {
+    childProcess.execSync(`npm dist-tag add electron@${localVersion} beta --otp=${process.env.ELECTRON_NPM_OTP}`)
+  }
+})
 .catch((err) => {
   console.error(`Error: ${err}`)
   process.exit(1)