Building Mac OS binaries
========================

✗ _This script does not produce reproducible output (yet!).
   Please help us remedy this._

This guide explains how to build Electrum binaries for macOS systems.


## 1. Building the binary

This needs to be done on a system running macOS or OS X. We use El Capitan (10.11.6) as building it
on High Sierra (or later)
makes the binaries [incompatible with older versions](https://github.com/pyinstaller/pyinstaller/issues/1191).

Another factor for the minimum supported macOS version is the
[bundled Qt version](https://github.com/spesmilo/electrum/issues/3685).

Before starting, make sure that the Xcode command line tools are installed (e.g. you have `git`).

#### 1.1a Get Xcode

Building the QR scanner (CalinsQRReader) requires full Xcode (not just command line tools).

The last Xcode version compatible with El Capitan is Xcode 8.2.1

Get it from [here](https://developer.apple.com/download/more/).

Unfortunately, you need an "Apple ID" account.

After downloading, uncompress it.

Make sure it is the "selected" xcode (e.g.):

    sudo xcode-select -s $HOME/Downloads/Xcode.app/Contents/Developer/

#### 1.1b Build QR scanner separately on newer Mac

Alternatively, you can try building just the QR scanner on newer macOS.

On newer Mac, run:

    pushd contrib/osx/CalinsQRReader; xcodebuild; popd
    cp -r contrib/osx/CalinsQRReader/build prebuilt_qr

Move `prebuilt_qr` to El Capitan: `contrib/osx/CalinsQRReader/prebuilt_qr`.


#### 1.2 Build Electrum

    cd electrum
    ./contrib/osx/make_osx
    
This creates both a folder named Electrum.app and the .dmg file.


## 2. Building the image deterministically (WIP)
The usual way to distribute macOS applications is to use image files containing the 
application. Although these images can be created on a Mac with the built-in `hdiutil`,
they are not deterministic.

Instead, we use the toolchain that Bitcoin uses: genisoimage and libdmg-hfsplus.
These tools do not work on macOS, so you need a separate Linux machine (or VM).

Copy the Electrum.app directory over and install the dependencies, e.g.:

    apt install libcap-dev cmake make gcc faketime
    
Then you can just invoke `package.sh` with the path to the app:

    cd electrum
    ./contrib/osx/package.sh ~/Electrum.app/