fix: Lazily import git-rev-sync in non-production

package.json

@@ -73,7 +73,6 @@
     "firefox-profile": "2.0.0",
     "fs-extra": "9.0.1",
     "fx-runner": "1.0.13",
-    "git-rev-sync": "2.0.0",
     "import-fresh": "3.2.1",
     "mkdirp": "1.0.4",
     "multimatch": "4.0.0",
@@ -116,6 +115,7 @@
     "eslint-plugin-flowtype": "5.2.0",
     "eslint-plugin-import": "2.22.0",
     "flow-bin": "0.129.0",
+    "git-rev-sync": "2.0.0",
     "html-entities": "1.3.1",
     "mocha": "8.0.1",
     "nyc": "15.1.0",

src/program.js

@@ -5,7 +5,6 @@ import {readFileSync} from 'fs';
 
 import camelCase from 'camelcase';
 import decamelize from 'decamelize';
-import git from 'git-rev-sync';
 import yargs from 'yargs';
 import { Parser as yargsParser } from 'yargs/yargs';
 
@@ -353,6 +352,11 @@ export function defaultVersionGetter(
     return JSON.parse(packageData).version;
   } else {
     log.debug('Getting version from the git revision');
+    // This branch is only reached during development.
+    // git-rev-sync is in devDependencies, and lazily imported using require.
+    // This also avoids logspam from https://github.com/mozilla/web-ext/issues/1916
+    // eslint-disable-next-line import/no-extraneous-dependencies
+    const git = require('git-rev-sync');
     return `${git.branch(absolutePackageDir)}-${git.long(absolutePackageDir)}`;
   }
 }

webpack.config.js

@@ -39,7 +39,12 @@ module.exports = {
   externals: [
     nodeExternals({
       modulesFromFile: {
-        excludeFromBundle: ['dependencies'],
+        // We shouldn't bundle devDependencies. E.g. git-rev-sync would be
+        // bundled if we omitted "devDependencies" from this list, which is
+        // undesired because the branch is never reached on production, so it
+        // is intentionally part of devDependencies to avoid the unnecessary
+        // dependency and bundling on production.
+        excludeFromBundle: ['dependencies', 'devDependencies'],
       },
     }),
   ],