Added an --if-present flag for not erroring on unspecified scripts.

Fixes #7354.

4 files changed, 25 insertions, 2 deletions

diff --git a/doc/misc/npm-config.md b/doc/misc/npm-config.md
index 7e4c10af2..e727e1666 100644
--- a/doc/misc/npm-config.md
+++ b/doc/misc/npm-config.md
@@ -243,7 +243,7 @@ If true, then only prints color codes for tty file descriptors.
 * Default: Infinity
 * Type: Number
 
-The depth to go when recursing directories for `npm ls`, 
+The depth to go when recursing directories for `npm ls`,
 `npm cache ls`, and `npm outdated`.
 
 For `npm outdated`, a setting of `Infinity` will be treated as `0`
@@ -390,6 +390,17 @@ A proxy to use for outgoing https requests. If the `HTTPS_PROXY` or
 `https_proxy` or `HTTP_PROXY` or `http_proxy` environment variables are set,
 proxy settings will be honored by the underlying `request` library.
 
+### if-present
+
+* Default: false
+* Type: Boolean
+
+If true, npm will not exit with an error code when `run-script` is invoked for
+a script that isn't defined in the `scripts` section of `package.json`. This
+option can be used when it's desirable to optionally run a script when it's
+present and fail if the script fails. This is useful, for example, when running
+scripts that may only apply for some builds in an otherwise generic CI setup.
+
 ### ignore-scripts
 
 * Default: false
diff --git a/lib/config/defaults.js b/lib/config/defaults.js
index a46e74b5b..e49ce210b 100644
--- a/lib/config/defaults.js
+++ b/lib/config/defaults.js
@@ -160,6 +160,7 @@ Object.defineProperty(exports, "defaults", {get: function () {
     , group : process.platform === "win32" ? 0
             : process.env.SUDO_GID || (process.getgid && process.getgid())
     , heading: "npm"
+    , "if-present": false
     , "ignore-scripts": false
     , "init-module": path.resolve(home, ".npm-init.js")
     , "init-author-name" : ""
@@ -262,6 +263,7 @@ exports.types =
   , "https-proxy" : [null, url]
   , "user-agent" : String
   , "heading": String
+  , "if-present": Boolean
   , "ignore-scripts": Boolean
   , "init-module": path
   , "init-author-name" : String
diff --git a/lib/run-script.js b/lib/run-script.js
index 7603e29e1..b6aa5fe7e 100644
--- a/lib/run-script.js
+++ b/lib/run-script.js
@@ -159,6 +159,8 @@ function run (pkg, wd, cmd, args, cb) {
           log.verbose("run-script using default platform env: env (Unix)")
           pkg.scripts[cmd] = "env"
         }
+      } else if (npm.config.get("if-present")) {
+        return cb(null);
       } else {
         return cb(new Error("missing script: " + cmd))
       }
diff --git a/test/tap/run-script.js b/test/tap/run-script.js
index fca9a76ff..35790684f 100644
--- a/test/tap/run-script.js
+++ b/test/tap/run-script.js
@@ -156,10 +156,18 @@ test('npm run-script nonexistent-script', function (t) {
   })
 })
 
-test('npm run-script restart when there isn"t restart', function (t) {
+test('npm run-script restart when there isn\'t restart', function (t) {
   common.npm(['run-script', 'restart'], opts, testOutput.bind(null, t, 'stop;start'))
 })
 
+test('npm run-script nonexistent-script with --if-present flag', function (t) {
+  common.npm(['run-script', '--if-present', 'nonexistent-script'], opts, function (er, code, stdout, stderr) {
+    t.ifError(er, 'npm run-script --if-present non-existent-script ran without issue')
+    t.notOk(stderr, 'should not generate errors')
+    t.end()
+  })
+})
+
 test('npm run-script no-params (lifecycle only)', function (t) {
   var expected = [
     'Lifecycle scripts included in scripted:',