Fix to issue #510 Watch doesn't detect cascading changes when nospawn is true

tasks/watch.js

@@ -62,10 +62,12 @@ module.exports = function(grunt) {
     var name = self.name || 'watch';
 
     // Close any previously opened watchers
-    watchers.forEach(function(watcher) {
-      watcher.close();
-    });
-    watchers = [];
+    if (!taskrun.running) {
+      watchers.forEach(function(watcher) {
+        watcher.close();
+      });
+      watchers = [];
+    }
 
     // Never gonna give you up, never gonna let you down
     if (grunt.config([name, 'options', 'forever']) !== false) {
@@ -111,80 +113,82 @@ module.exports = function(grunt) {
       }
 
       // Create watcher per target
-      watchers.push(new Gaze(patterns, target.options, function(err) {
-        if (err) {
-          if (typeof err === 'string') {
-            err = new Error(err);
+      if (!taskrun.running) {
+        watchers.push(new Gaze(patterns, target.options, function(err) {
+          if (err) {
+            if (typeof err === 'string') {
+              err = new Error(err);
+            }
+            grunt.log.writeln('ERROR'.red);
+            grunt.fatal(err);
+            return taskrun.done();
           }
-          grunt.log.writeln('ERROR'.red);
-          grunt.fatal(err);
-          return taskrun.done();
-        }
-
-        // Log all watched files with --verbose set
-        if (grunt.option('verbose')) {
-          var watched = this.watched();
-          Object.keys(watched).forEach(function(watchedDir) {
-            watched[watchedDir].forEach(function(watchedFile) {
-              grunt.log.writeln('Watching ' + path.relative(process.cwd(), watchedFile) + ' for changes.');
+
+          // Log all watched files with --verbose set
+          if (grunt.option('verbose')) {
+            var watched = this.watched();
+            Object.keys(watched).forEach(function(watchedDir) {
+              watched[watchedDir].forEach(function(watchedFile) {
+                grunt.log.writeln('Watching ' + path.relative(process.cwd(), watchedFile) + ' for changes.');
+              });
             });
-          });
-        }
+          }
 
-        // On changed/added/deleted
-        this.on('all', function(status, filepath) {
+          // On changed/added/deleted
+          this.on('all', function(status, filepath) {
 
-          // Skip events not specified
-          if (!_.includes(target.options.event, 'all') &&
-              !_.includes(target.options.event, status)) {
-            return;
-          }
+            // Skip events not specified
+            if (!_.includes(target.options.event, 'all') &&
+                !_.includes(target.options.event, status)) {
+              return;
+            }
 
-          filepath = path.relative(eventCwd, filepath);
+            filepath = path.relative(eventCwd, filepath);
 
-          // Skip empty filepaths
-          if (filepath === '') {
-            return;
-          }
+            // Skip empty filepaths
+            if (filepath === '') {
+              return;
+            }
 
-          // If Gruntfile.js changed, reload self task
-          if (target.options.reload || /gruntfile\.(js|coffee)/i.test(filepath)) {
-            taskrun.reload = true;
-          }
+            // If Gruntfile.js changed, reload self task
+            if (target.options.reload || /gruntfile\.(js|coffee)/i.test(filepath)) {
+              taskrun.reload = true;
+            }
 
-          // Emit watch events if anyone is listening
-          if (grunt.event.listeners('watch').length > 0) {
-            grunt.event.emit('watch', status, filepath, target.name);
-          }
+            // Emit watch events if anyone is listening
+            if (grunt.event.listeners('watch').length > 0) {
+              grunt.event.emit('watch', status, filepath, target.name);
+            }
 
-          // Group changed files only for display
-          changedFiles[filepath] = status;
+            // Group changed files only for display
+            changedFiles[filepath] = status;
 
-          // Add changed files to the target
-          if (taskrun.targets[target.name]) {
-            if (!taskrun.targets[target.name].changedFiles) {
-              taskrun.targets[target.name].changedFiles = Object.create(null);
+            // Add changed files to the target
+            if (taskrun.targets[target.name]) {
+              if (!taskrun.targets[target.name].changedFiles) {
+                taskrun.targets[target.name].changedFiles = Object.create(null);
+              }
+              taskrun.targets[target.name].changedFiles[filepath] = status;
             }
-            taskrun.targets[target.name].changedFiles[filepath] = status;
-          }
 
-          // Queue the target
-          if (taskrun.queue.indexOf(target.name) === -1) {
-            taskrun.queue.push(target.name);
-          }
+            // Queue the target
+            if (taskrun.queue.indexOf(target.name) === -1) {
+              taskrun.queue.push(target.name);
+            }
 
-          // Run the tasks
-          taskrun.run();
-        });
+            // Run the tasks
+            taskrun.run();
+          });
 
-        // On watcher error
-        this.on('error', function(err) {
-          if (typeof err === 'string') {
-            err = new Error(err);
-          }
-          grunt.log.error(err.message);
-        });
-      }));
+          // On watcher error
+          this.on('error', function(err) {
+            if (typeof err === 'string') {
+              err = new Error(err);
+            }
+            grunt.log.error(err.message);
+          });
+        }));
+      }
     });
 
   });

test/fixtures/nospawn/Gruntfile.js

@@ -5,6 +5,12 @@ module.exports = function(grunt) {
   var port = 1337;
 
   grunt.initConfig({
+    simplecopy: {
+      cascade: {
+        src: 'lib/source.js',
+        dest: 'lib/destination.js',
+      },
+    },
     watch: {
       nospawn: {
         files: ['lib/nospawn.js'],
@@ -17,6 +23,16 @@ module.exports = function(grunt) {
         files: ['lib/spawn.js'],
         tasks: ['server'],
       },
+      cascading: {
+        files: ['lib/source.js'],
+        tasks: ['simplecopy:cascade'],
+        options: {
+          nospawn: true,
+        },
+      },
+      cascaded: {
+        files: ['lib/destination.js'],
+      },
       interrupt: {
         files: ['lib/interrupt.js'],
         tasks: ['long', 'long', 'long'],
@@ -28,6 +44,9 @@ module.exports = function(grunt) {
     },
   });
 
+  // Load the simplecopy task
+  grunt.loadTasks('../tasks');
+
   // Load this watch task
   grunt.loadTasks('../../../tasks');
 

test/fixtures/nospawn/lib/destination.js

@@ -0,0 +1 @@
+var cascading = true;

test/fixtures/nospawn/lib/source.js

@@ -0,0 +1 @@
+var cascading = true;

test/fixtures/tasks/simplecopy.js

@@ -0,0 +1,31 @@
+var fs  = require('fs');
+
+module.exports = function(grunt) {
+  'use strict';
+  grunt.registerMultiTask('simplecopy', 'A task that simply copy a file.', function() {
+    var src = this.data.src;
+    var dest = this.data.dest;
+    var done = this.async();
+
+    var rd = fs.createReadStream(src);
+    rd.on("error", function(err) {
+      grunt.fail.fatal(err);
+      done();
+    });
+    var wr = fs.createWriteStream(dest);
+    wr.on("error", function(err) {
+      grunt.fail.fatal(err);
+      done();
+    });
+    wr.on("close", function(ex) {
+      if (ex) {
+        grunt.fail.fatal(ex);
+      } else {
+        grunt.log.writeln('Copied ' + src + ' to ' + dest + '.');
+      }
+      done();
+    });
+    rd.pipe(wr);
+  });
+};
+

test/tasks/nospawn_test.js

@@ -62,4 +62,20 @@ exports.nospawn = {
       test.done();
     });
   },
+  cascading: function(test) {
+    test.expect(2);
+    var cwd = path.resolve(fixtures, 'nospawn');
+    var assertWatch = helper.assertTask('watch', {cwd: cwd});
+    assertWatch(function() {
+      var write = 'var cascading = true;';
+      grunt.file.write(path.join(cwd, 'lib', 'source.js'), write);
+    }, function(result) {
+      helper.verboseLog(result);
+      test.ok(/File "lib[\/\\]source\.js" changed/.test(result),
+              'Cascading file should have been detected.');
+      test.ok(/File "lib[\/\\]destination\.js" changed/.test(result),
+              'Cascaded file should have been detected.');
+      test.done();
+    });
+  },
 };