mv: show error when overwriting recently created file shelljs#631

src/mv.js

@@ -11,6 +11,14 @@ common.register('mv', _mv, {
   },
 });
 
+// Checks if cureent file was created recently
+function checkRecentCreated(sources, index) {
+  var lookedSource = sources[index];
+  return sources.slice(0, index).some(function (src) {
+    return path.basename(src) === path.basename(lookedSource);
+  });
+}
+
 //@
 //@ ### mv([options ,] source [, source ...], dest')
 //@ ### mv([options ,] source_array, dest')
@@ -55,7 +63,7 @@ function _mv(options, sources, dest) {
     common.error('dest file already exists: ' + dest);
   }
 
-  sources.forEach(function (src) {
+  sources.forEach(function (src, srcIndex) {
     if (!fs.existsSync(src)) {
       common.error('no such file or directory: ' + src, { continue: true });
       return; // skip file
@@ -70,6 +78,16 @@ function _mv(options, sources, dest) {
       thisDest = path.normalize(dest + '/' + path.basename(src));
     }
 
+    var thisDestExists = fs.existsSync(thisDest);
+
+    if (thisDestExists && checkRecentCreated(sources, srcIndex)) {
+      // cannot overwrite file created recently in current execution, but we want to continue copying other files
+      if (!options.no_force) {
+        common.error("will not overwrite just-created '" + thisDest + "' with '" + src + "'", { continue: true });
+      }
+      return;
+    }
+
     if (fs.existsSync(thisDest) && options.no_force) {
       common.error('dest file already exists: ' + thisDest, { continue: true });
       return; // skip file