Gracefully fail using a --dry-run flag on the hook

appveyor.yml

@@ -0,0 +1,28 @@
+environment:
+  matrix:
+  - nodejs_version: "0.8"
+  - nodejs_version: "0.10"
+  - nodejs_version: "0.12"
+  - nodejs_version: "1.0"
+
+matrix:
+  fast_finish: true
+  allow_failures:
+    - platform: x86
+    - platform: x64
+
+platform:
+  - x86
+  - x64
+
+install:
+  - ps: Install-Product node $env:nodejs_version $env:platform
+  - npm install -g npm@2.x.x
+  - npm install
+
+test_script:
+  - node --version
+  - npm --version
+  - npm test
+
+build: off

hook

@@ -16,13 +16,29 @@ NODE=`which node 2> /dev/null`
 NODEJS=`which nodejs 2> /dev/null`
 IOJS=`which iojs 2> /dev/null`
 LOCAL="/usr/local/bin/node"
+BINARY=
 
+#
+# Figure out which binary we need to use for our script execution.
+#
 if [[ -n "$NODE" ]]; then
-  "$NODE" $("$NODE" -e "console.log(require.resolve('pre-commit'))")
+  BINARY="$NODE"
 elif [[ -n "$NODEJS" ]]; then
-  "$NODEJS" $("$NODEJS" -e "console.log(require.resolve('pre-commit'))")
+  BINARY="$NODEJS"
 elif [[ -n "$IOJS" ]]; then
-  "$IOJS" $("$IOJS" -e "console.log(require.resolve('pre-commit'))")
+  BINARY="$IOJS"
 elif [[ -x "$LOCAL" ]]; then
-  "$LOCAL" $("$LOCAL" -e "console.log(require.resolve('pre-commit'))")
+  BINARY="$LOCAL"
+fi
+
+#
+# Add --dry-run cli flag support so we can execute this hook without side affects
+# and see if it works in the current environment
+#
+if [[ $* == *--dry-run* ]]; then
+  if [[ -z "$BINARY" ]]; then
+    exit 1
+  fi
+else
+  "$BINARY" $("$BINARY" -e "console.log(require.resolve('pre-commit'))")
 fi

install.js

@@ -5,6 +5,7 @@
 //
 var fs = require('fs')
   , path = require('path')
+  , shelly = require('shelljs')
   , hook = path.join(__dirname, './hook')
   , root = path.resolve(__dirname, '../..')
   , exists = fs.existsSync || path.existsSync;
@@ -19,6 +20,18 @@ var git = path.resolve(root, '.git')
   , hooks = path.resolve(git, 'hooks')
   , precommit = path.resolve(hooks, 'pre-commit');
 
+//
+// Make sure that we can execute the hook without any issues before continuing.
+//
+if (shelly.exec(hook +' --dry-run', { silent: true }).code !== 0) {
+  console.error('pre-commit:');
+  console.error('pre-commit: The --dry-run of the pre-commit hook failed to execute.');
+  console.error('pre-commit:');
+  console.error('pre-commit: The hook was not installed.');
+  console.error('pre-commit:');
+  return;
+}
+
 //
 // Bail out if we don't have an `.git` directory as the hooks will not get
 // triggered. If we do have directory create a hooks folder if it doesn't exist.