Xcode warning: “Multiple build commands for output

问题:

I am getting an error like this:

[WARN]Warning: Multiple build commands for output file /Developer/B/Be/build/Release-iphonesimulator/BB.app/no.png

[WARN]Warning: Multiple build commands for output file /Developer/B/Be/build/Release-iphonesimulator/BB.app/d.png

[WARN]Warning: Multiple build commands for output file /Developer/B/Be/build/Release-iphonesimulator/BB.app/n.png

But I have checked Xcode and I don't see any duplicates of such files at all. As this post in the Apple Mailing Lists say, there are no duplicates.

回答1:

In the Project Navigator, select your Xcode Project file. This will show you the project settings as well as the targets in the project. Look in the "Copy Bundle Resources" Build Phase. You should find the offending files in that list twice. Delete the duplicate reference.

Xcode is complaining that you are trying to bundle the same file with your application two times.

回答2:

This is easily caused when you add git based subprojects. Xcode isn't smart enough to ignore the .git subfolder even though you can't see it from finder, so it will get very confused that there are multiple files named "master" or "exclude", (standard git repo files). With Xcode4, go to the project (root of the left tree) then click your app target and expand "Copy Bundle Resources", then remove all the references to .git, you shouldn't need them baked into your app anyway.

回答3:

Actually The answer to this is very simple.

In your xcode search for the files which raises the warning, and just delete it.

The Xcode will show only one reference of that file in the search results, but dont stop there, go ahead and delete it. (better make a back up to your project file before delete operation)

Now do a build, you will see the warning removed. (this answer is for a previous version of xcode)

回答4:

This is not an Xcode bug, though the warning message is not helpful enough to describe the real cause.

This error message occurs when you have several files in your project that have the same name. You just have to delete or rename the files with duplicate names and the problem is solved.

回答5:

This happens if you have 2 files with the same name in the project. Even though files are in groups in XCode when the project is compiled all of the files end up in the same directory. In other words if you have /group1/image.jpg and /group2/image.jpg the compiled project will only have one of the two image.jpg files.

回答6:

As previously mentioned, this issue can be seen if you have multiple files with the same name, but in different groups (yellow folders) in the project navigator. In my case, this was intentional as I had multiple subdirectories each with a "preview.jpg" that I wanted copying to the app bundle:

In this situation, you need to ensure that Xcode recognises the directory reference (blue folder icon), not just the groups.

Remove the offending files and choose "Remove Reference" (so we don't delete them entirely):

Re-add them to the project by dragging them back into the project navigator. In the dialog that appears, choose "Create folder references for any added folders":

Notice that the files now have a blue folder icon in the project navigator:

---

If you now look under the "Copy Bundle Resources" section of the target's build phases, you will notice that there is a single entry for the entire folder, rather than entries for each item contained within the directory. The compiler will not complain about multiple build commands for those files.

回答7:

This is not a bug. Xcode assists can assist you. Select the target, to the left in the project Navigator. Click on "Validate settings" at the bottom of the settings. Xcode will check the settings and removes duplicates if possible.

回答8:

another version of this situation can occur when there are duplicates in the Headers build phase.

to fix this …

1. go to your project target
2. choose Build Phases
3. choose the Headers build phase
4. enter the name shown in the warning
5. notice the two (or more) items
6. find the +|- boxes in the lower left corner
7. select one of the items, and click the - button

回答9:

In my case the issue was caused by the same name of target and folder inside a group.

Just rename conflicted file or folder to resolve the issue.

回答10:

I'm pretty sure this can be caused by an XCode 4 bug, at least in the cases that I've encountered it in.

It happens if you add multiple language dependent files to the project at the same time. I found this out by looking through the git differences. I did nothing in the commit but add some new localized nib files. But looking back at the difference of the project.pbxproj file it showed a bunch of new duplicate references added for files that were already in the project before. The files it did this too seemed random to me.

I reproduced this same exact behavior multiple times.

Deleting these files from the project does not fix the problem because it only deletes the original reference and leaves the duplicates. The only way to fix it is to go back a commit and start over, or hand edit the project file, which is a really good way to screw it up even more since it's hard to tell which duplicates to remove and you have to do it in a ton of different places.

Xcode 4 is just a huge disappointment for me.

回答11:

I found a pretty easy solution for this:

1. Select the file causing the problem from the project navigator
2. Uncheck the target membership from the file inspector
3. Build the project
4. Recheck the target membership for the file again

The warning is gone! Check this image for reference.

回答12:

This happends because ur "no.png" "d.png" and "n.png" are duplicated in resources . Just look for delete dublicated files and delete.

回答13:

The error seem to appear when u have more than one reference of the same file. I had 2 files of the same name and got this error. When I delete one of them the error disappear..

回答14:

Yet another variation on this issue. I had the same message come up none of the previously suggested solutions solved the problem (I definitely only had one copy of the offending file for instance).

My solution was to edit the project.pbxproj file in a text editor (after quitting XCode and backing up the file of course) and remove all references to the offending file. Then, after starting XCode again, I manually added the file back into the project and everything was ok.

(My suspicion is that this problem happened to me because of a manual, ie: non-XCode, merge of the project file.)

回答15:

Open the Frameworks folder in your project and make sure there are only frameworks inside. I added by mistake the whole Developer folder!

回答16:

I had the same problem minutes ago. I've mentioned changing the 'deployment target' fixed my problem.

回答17:

For me the Target > Build Settings > Packaging > Product Name was set to the same thing as another value referenced in a .plist file which was custom to my app. Eventually due to our build process this creates duplicate files.

回答18:

Swift 3: (but also the older versions) it happen when I have assets with duplicates. Just rename the files with this issue and all go well.

It could happen also when you have made a Assets.xcassets and you have renamed the duplicates with new names so after time you forgot it and remove it to add the folder references but this one return to the duplicate files problem..

回答19:

What worked for me:

1. Drag repo to the trash.
2. re-clone your repo.
3. set up your repo with correct remote tracking. git remote add <url.git>, or git remote set-url <url.git>

This absolutely worked for me. In my case for some elusive reason, when I ran git pull upstream develop for a local dependency, git would pull in/generate duplicate files from multiple commits.

After following the above steps, the issue went away and git pull upstream develop was no longer pulling from multiple commits at once. Perhaps there was a weird git cache for my repo.

回答20:

One of simple way is,

• Go to App target
• Go to Build Phases
• Output files
• Delete path of out put files, then build project. It will run successfully.