chore(docs): Enable ignore_build.mjs to be smarter about when building docs

Author: Tobbe

docs/ignore_build.mjs

@@ -1,38 +1,46 @@
 // We only want Netlify to build the site if a PR changes files in this
 // directory (./docs).
 // See https://docs.netlify.com/configure-builds/ignore-builds.
-// Netlify runs this via Node.js v18.
+// Netlify runs this via Node.js v22 (even though their docs say Node 18).
+// If the exit-code is 0, the build will be ignored.
 
 import { execSync } from 'node:child_process'
 
 async function main() {
-  const branch = process.env.BRANCH
-
-  // Reproduce the default behavior for main.
-  // See https://docs.netlify.com/configure-builds/ignore-builds/#mimic-default-behavior.
-  // `execSync` throws if the process times out or has a non-zero exit code.
-  if (branch === 'main') {
+  if (process.env.BRANCH === 'main') {
     try {
+      // Reproduce the default behavior for main.
+      // See https://docs.netlify.com/configure-builds/ignore-builds/#mimic-default-behavior.
+      // `execSync` throws if the process times out or has a non-zero exit code.
       execSync('git diff --quiet $CACHED_COMMIT_REF $COMMIT_REF')
-    } catch (error) {
-      process.exitCode = 1
+      // If we come here, git diff exited with code 0, which means that there
+      // were no changes since the last cached build. So no need to build -> We
+      // can exit with 0 to ignore this build.
+      process.exitCode = 0
       return
+    } catch {
+      // Continue to check what files changed
     }
   }
 
   // Query the GithHub API to get the changed files in the PR
   // See below for REVIEW_ID
   // https://docs.netlify.com/configure-builds/environment-variables/#git-metadata
-  const url = `https://api.github.com/repos/cedarjs/cedar/pulls/${process.env.REVIEW_ID}/files?per_page=100`
+  // If we don't have a review ID the best we can do is check the commit (this
+  // happens when we're committing straight to main)
+  const url = process.env.REVIEW_ID
+    ? `https://api.github.com/repos/cedarjs/cedar/pulls/${process.env.REVIEW_ID}/files?per_page=100`
+    : `https://api.github.com/repos/cedarjs/cedar/commits/${process.env.COMMIT_REF}`
   const resp = await fetch(url, {
     headers: {
-      Authorization: `Bearer ${process.env.RW_GITHUB_TOKEN}`,
+      Authorization: `Bearer ${process.env.CEDAR_GITHUB_TOKEN}`,
       ['X-GitHub-Api-Version']: '2022-11-28',
       Accept: 'application/vnd.github+json',
     },
   })
   const json = await resp.json()
-  const changedFiles = json.map((file) => file.filename)
+  // Account for both PRs and commits in the returned json object
+  const changedFiles = (json.files || json).map((file) => file.filename)
 
   console.log({
     changedFiles,

docs/netlify.toml

@@ -2,7 +2,7 @@
 base = "docs"
 publish = "build"
 command = "yarn build"
-# ignore = "node ignore_build.mjs"
+ignore = "node ignore_build.mjs"
 
 [build.environment]
 NODE_OPTIONS = "--max-old-space-size=4096"