Problem with Capacitor logging

Capacitor only logs to the Xcode console (or Safari console) but not to the iOS device console (aka the native log), for example from your Capacitor plugins or Cordova plugins, or console.log and console.debug statements in your code.

Having the debug log in Xcode or Safari only is fine when debugging during development or in Testflight. But once your app is published to the AppStore and has some specific error that does not show in dev or Testflight, you need to have log write to the iOS device log, which can be read by console.app on your Mac.

Solution

There is a Capacitor feature request regarding this but if you don’t want to wait for that, this is how to quickly fix it in your project:

1. Open the file capacitor/ios/Capacitor/Capacitor/CAPLog.swift either from your favourite editor or directly in Xcode.
2. Comment out the line starting with Swift.print
3. Instead add the line: NSLog(String(describing: item))

public class CAPLog {
    public static var enableLogging: Bool = true

    public static func print(_ items: Any..., separator: String = " ", terminator: String = "\n") {
        if enableLogging {
            for (itemIndex, item) in items.enumerated() {
                //Swift.print("\(item)".prefix(4068), terminator: itemIndex == items.count - 1 ? terminator : separator)
                NSLog(String(describing: item))
            }
        }
    }
}

Now you are ready to build and upload to Apple App Store. Once approved by Apple, start debugging your production build in console.app.

This was tested using Capacitor 3.6.0 / @capacitor/ios 3.6.0 (on an Ionic Framework 6 project)

Note on performance

Swift.print is a more resource effective, but also more limited, way of logging. I doubt that this has much practical impact, but this is something to consider, you may want to revert back to Swift.print after you’re done debugging.

Note on logging

I used NSLog but there are also other ways to use logging that you may want to look into. For example Logger and Apple’s concept of Universal logging / Unified logging system.

Did this solution help you?

I hope this helped! Please comment if it did, or if you had any problem with it. Also let me know if you got it working (or not) using other versions or if you found a better solution – it will help me and others!

Background – pre Xcode 11 / Xcode 12

Before Xcode 11 the “normal” way to auto increment build number was to read current build number from Info.plist using the MacOS PlistBuddy tool and then increment that number and write the updated build number back to Info.plist, again using PlistBuddy. Or you could use avgtool or some 3rd party solution.

However, with Xcode11 (and currently Xcode12) version number and buildnumber are set in the pbxproj file, and Info.plist only reference what is set in pbxproj.

This change got my old script to generate an error on build: Command PhaseScriptExecution failed with a nonzero exit code

$(CURRENT_PROJECT_VERSION) + 1: syntax error: operand expected (error token is "$(CURRENT_PROJECT_VERSION) + 1")
Command PhaseScriptExecution failed with a nonzero exit code

This is what Info.plist now looks like in Xcode11 / Xcode12, i.e. there is no longer an actual build number to read from Info.plist, only a reference to what is set in the pbxproj file.

<key>CFBundleShortVersionString</key> 
<string>$(MARKETING_VERSION)</string> 

<key>CFBundleVersion</key>
<string>$(CURRENT_PROJECT_VERSION)</string>

Solution for Xcode 11 / Xcode 12

So, in Xcode 11/12 we now need to update the pbxproj file instead of Info.plist.

Use this script to auto increment build number:

buildNumber=$(xcodebuild -showBuildSettings | grep CURRENT_PROJECT_VERSION | tr -d 'CURRENT_PROJECT_VERSION =')
buildNumber=`echo $buildNumber +1|bc`
xcrun agvtool new-version $buildNumber

To add the script in Xcode 12, follow these steps:

1. Select your Project Target (Target, not Project)
2. Select Build Phases
3. Add a new Build Phase by clicking the plus (+) icon on top left
4. If you wish you can rename the new Build phase, e.g. Set Build Number
5. Copy the script above and paste it
6. You can leave all other Build Phase settings as default
7. Done – Build your project and watch build number increment with 1 for each build

This was latest tested on Xcode 12.5 and macOS Big Sur 11.5.2 on a MacBook Air M1

Did this solution help you?

I hope this helped! Please comment if it did, or if you had any problem with it. Also let me know if you got it working (or not) using other versions or if you found a better solution – it will help me and others!

It is aimed for our customers, who are mainly non-developers, on the steps for first time setup Apple Developer and App Store Connect for us to be able to sign and upload apps that we have developed for them. But it should be usable for any non-developer or developer in that same situation.

https://www.mobilapp.nu/2020/02/12/tutorial-add-your-app-to-apple-app-store-preparations-for-non-developers/