Installing PyCall in Julia 1.2 fails on Mac OS X

I tried installing PyCall on a fresh install of Julia 1.2 but got an error stating setuptools can't be removed. Any idea what might be going on:

```
julia> Pkg.add("PyCall")
Cloning default registries into `~/.julia`
Cloning registry from "https://github.com/JuliaRegistries/General.git"
Added registry `General` to `~/.julia/registries/General`
Resolving package versions...
Installed VersionParsing ───── v1.1.3
Installed Tokenize ─────────── v0.5.6
Installed Parsers ──────────── v0.3.7
Installed Compat ───────────── v2.2.0
Installed OrderedCollections ─ v1.1.0
Installed DataStructures ───── v0.17.2
Installed MacroTools ───────── v0.5.1
Installed PyCall ───────────── v1.91.2
Installed Conda ────────────── v1.3.0
Installed CSTParser ────────── v0.6.2
Installed JSON ─────────────── v0.21.0
Updating `~/.julia/environments/v1.2/Project.toml`
[438e738f] + PyCall v1.91.2
Updating `~/.julia/environments/v1.2/Manifest.toml`
[00ebfdb7] + CSTParser v0.6.2
[34da2185] + Compat v2.2.0
[8f4d0f93] + Conda v1.3.0
[864edb3b] + DataStructures v0.17.2
[682c06a0] + JSON v0.21.0
[1914dd2f] + MacroTools v0.5.1
[bac558e1] + OrderedCollections v1.1.0
[69de0a69] + Parsers v0.3.7
[438e738f] + PyCall v1.91.2
[0796e94c] + Tokenize v0.5.6
[81def892] + VersionParsing v1.1.3
[2a0f44e3] + Base64
[ade2ca70] + Dates
[8bb1440f] + DelimitedFiles
[8ba89e20] + Distributed
[b77e0a4c] + InteractiveUtils
[76f85450] + LibGit2
[8f399da3] + Libdl
[37e2e46d] + LinearAlgebra
[56ddb016] + Logging
[d6f4376e] + Markdown
[a63ad114] + Mmap
[44cfe95a] + Pkg
[de0858da] + Printf
[3fa0cd96] + REPL
[9a3f8284] + Random
[ea8e919c] + SHA
[9e88b42a] + Serialization
[1a1011a3] + SharedArrays
[6462fe0b] + Sockets
[2f01184e] + SparseArrays
[10745b16] + Statistics
[8dfed614] + Test
[cf7118a7] + UUIDs
[4ec0a83e] + Unicode
Building Conda ─→ `~/.julia/packages/Conda/kLXeC/deps/build.log`
Building PyCall → `~/.julia/packages/PyCall/ttONZ/deps/build.log`
┌ Error: Error building `PyCall`, showing the last 100 of log:
│ Collecting package metadata (current_repodata.json): ...working... done
│ Solving environment: ...working... done
│
│ ## Package Plan ##
│
│ environment location: /Users/kamesh/.julia/conda/3
│
│ added / updated specs:
│ - conda
│
│
│ The following packages will be downloaded:
│
│ package | build
│ ---------------------------|-----------------
│ asn1crypto-1.0.1 | py37_0 161 KB
│ ca-certificates-2019.8.28 | 0 133 KB
│ certifi-2019.9.11 | py37_0 154 KB
│ chardet-3.0.4 | py37_1003 174 KB
│ conda-4.7.12 | py37_0 3.0 MB
│ conda-package-handling-1.6.0| py37h1de35cc_0 1.3 MB
│ openssl-1.1.1d | h1de35cc_2 2.2 MB
│ pysocks-1.7.1 | py37_0 30 KB
│ sqlite-3.30.0 | ha441bb4_0 2.4 MB
│ tqdm-4.36.1 | py_0 50 KB
│ ------------------------------------------------------------
│ Total: 9.6 MB
│
│ The following packages will be REMOVED:
│
│ bzip2-1.0.8-h1de35cc_0
│ libarchive-3.3.3-h786848e_5
│ libiconv-1.15-hdd342a3_7
│ libxml2-2.9.9-hf6e021a_1
│ lz4-c-1.8.1.2-h1de35cc_0
│ lzo-2.10-h362108e_2
│ pip-19.1.1-py37_0
│ python-libarchive-c-2.8-py37_11
│ python.app-2-py37_9
│ setuptools-41.0.1-py37_0
│ wheel-0.33.4-py37_0
│ zstd-1.3.7-h5bba6e5_0
│
│ The following packages will be UPDATED:
│
│ asn1crypto 0.24.0-py37_0 --> 1.0.1-py37_0
│ ca-certificates 2019.5.15-0 --> 2019.8.28-0
│ certifi 2019.6.16-py37_0 --> 2019.9.11-py37_0
│ chardet 3.0.4-py37_1 --> 3.0.4-py37_1003
│ conda 4.7.10-py37_0 --> 4.7.12-py37_0
│ conda-package-han~ 1.3.11-py37_0 --> 1.6.0-py37h1de35cc_0
│ openssl 1.1.1c-h1de35cc_1 --> 1.1.1d-h1de35cc_2
│ pysocks 1.7.0-py37_0 --> 1.7.1-py37_0
│ sqlite 3.29.0-ha441bb4_0 --> 3.30.0-ha441bb4_0
│ tqdm 4.32.1-py_0 --> 4.36.1-py_0
│
│
│
│ Downloading and Extracting Packages
certifi-2019.9.11 | 154 KB | ########## | 100%
tqdm-4.36.1 | 50 KB | ########## | 100%
conda-package-handli | 1.3 MB | ########## | 100%
asn1crypto-1.0.1 | 161 KB | ########## | 100%
chardet-3.0.4 | 174 KB | ########## | 100%
ca-certificates-2019 | 133 KB | ########## | 100%
openssl-1.1.1d | 2.2 MB | ########## | 100%
conda-4.7.12 | 3.0 MB | ########## | 100%
sqlite-3.30.0 | 2.4 MB | ########## | 100%
pysocks-1.7.1 | 30 KB | ########## | 100%
│ Preparing transaction: ...working... done
│ Verifying transaction: ...working... failed
│
│ RemoveError: 'setuptools' is a dependency of conda and cannot be removed from
│ conda's operating environment.
│
│ ┌ Info: Using the Python distribution in the Conda package by default.
│ └ To use a different Python version, set ENV["PYTHON"]="pythoncommand" and re-run Pkg.build("PyCall").
│ [ Info: Downloading miniconda installer ...
│ [ Info: Installing miniconda ...
│ [ Info: Running `conda config --add channels defaults --file /Users/kamesh/.julia/conda/3/condarc-julia.yml --force` in root environment
│ [ Info: Running `conda update -y conda` in root environment
│ ERROR: LoadError: failed process: Process(setenv(`/Users/kamesh/.julia/conda/3/bin/conda update -y conda`,["CLICOLOR=1", "LSCOLORS=CxFxGxDxbxegedabagGxGx", "PATH=/Applications/Julia-1.2.app/Contents/Resources/julia/bin/:/anaconda3/bin:/anaconda3/condabin:/anaconda3/bin:/opt/local/bin:/opt/local/sbin:/Developer/NVIDIA/CUDA-9.2/bin:/Library/TeX/texbin:/Applications/MATLAB_R2014a.app/bin:/Applications/MATLAB_R2011b.app/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/TeX/texbin:/opt/X11/bin:/Library/TeX/Distributions/.DefaultTeX/Contents/Programs/texbin", "PWD=/Users/kamesh", "XPC_FLAGS=0x0", "_CE_M=", "XPC_SERVICE_NAME=0", "TERM_PROGRAM=Apple_Terminal", "DISPLAY=/private/tmp/com.apple.launchd.H5wPiV35rm/org.macosforge.xquartz:0", "SHELL=/bin/bash" … "Apple_PubSub_Socket_Render=/private/tmp/com.apple.launchd.btcQWzUiSj/Render", "_CE_CONDA=", "USER=kamesh", "TERM=xterm", "MKL_NUM_THREADS=8", "TERM_PROGRAM_VERSION=421.1", "JULIA_NUM_THREADS=8", "HOME=/Users/kamesh", "OPENBLAS_MAIN_FREE=1", "PYTHONIOENCODING=UTF-8"]), ProcessExited(1)) [1]
│
│ Stacktrace:
│ [1] pipeline_error at ./process.jl:813 [inlined]
│ [2] #run#536(::Bool, ::typeof(run), ::Cmd) at ./process.jl:728
│ [3] run at ./process.jl:726 [inlined]
│ [4] runconda(::Cmd, ::String) at /Users/kamesh/.julia/packages/Conda/kLXeC/src/Conda.jl:113
│ [5] runconda(::Cmd) at /Users/kamesh/.julia/packages/Conda/kLXeC/src/Conda.jl:111
│ [6] _install_conda(::String, ::Bool) at /Users/kamesh/.julia/packages/Conda/kLXeC/src/Conda.jl:172
│ [7] _install_conda(::String) at /Users/kamesh/.julia/packages/Conda/kLXeC/src/Conda.jl:152
│ [8] runconda(::Cmd, ::String) at /Users/kamesh/.julia/packages/Conda/kLXeC/src/Conda.jl:111
│ [9] #add#1(::String, ::typeof(Conda.add), ::String, ::String) at /Users/kamesh/.julia/packages/Conda/kLXeC/src/Conda.jl:184
│ [10] add at /Users/kamesh/.julia/packages/Conda/kLXeC/src/Conda.jl:183 [inlined] (repeats 2 times)
│ [11] top-level scope at /Users/kamesh/.julia/packages/PyCall/ttONZ/deps/build.jl:84
│ [12] include at ./boot.jl:328 [inlined]
│ [13] include_relative(::Module, ::String) at ./loading.jl:1094
│ [14] include(::Module, ::String) at ./Base.jl:31
│ [15] include(::String) at ./client.jl:431
│ [16] top-level scope at none:5
│ in expression starting at /Users/kamesh/.julia/packages/PyCall/ttONZ/deps/build.jl:43
│
│ Full log at /Users/kamesh/.julia/packages/PyCall/ttONZ/deps/build.log
└ @ Pkg.Operations /Users/sabae/buildbot/worker/package_macos64/build/usr/share/julia/stdlib/v1.2/Pkg/src/backwards_compatible_isolation.jl:647

```

Start by reproducing the Julia 1.2 installation failure and inspect the referenced Conda build log. Read Conda.jl around lines 111–184 and PyCall's deps/build.jl around line 84 to trace the Conda update; done means a fresh PyCall installation completes without the setuptools RemoveError.

Written by the indexing model from the issue text.