PyPlot causing "infinite loop" on julia 1.3

[scottstanie]

Can't seem to get PyPlot to work

(v1.3) pkg> add PyPlot
  Updating registry at `~/.julia/registries/General`
  Updating git-repo `https://github.com/JuliaRegistries/General.git`
 Resolving package versions...
  Updating `~/.julia/environments/v1.3/Project.toml`
  [d330b81b] + PyPlot v2.8.1
  Updating `~/.julia/environments/v1.3/Manifest.toml`
  [b964fa9f] + LaTeXStrings v1.0.3
  [d330b81b] + PyPlot v2.8.1
using PyPlot
[ Info: Recompiling stale cache file /home/scott/.julia/compiled/v1.3/PyPlot/oatAj.ji for PyPlot [d330b81b-6aea-500a-939a-2ce795aea3ee]

julia> plot(collect(1:5), rand(5))
error in background error handler:
out of stack space (infinite loop?)
    while executing
"::tcl::Bgerror {out of stack space (infinite loop?)} {-code 1 -level 0 -errorcode NONE -errorinfo {out of stack space (infinite loop?)
....

julia> versioninfo()
Julia Version 1.3.0-alpha.0
Commit 6c11e7c2c4 (2019-07-23 01:46 UTC)
Platform Info:
  OS: Linux (x86_64-pc-linux-gnu)
  CPU: Intel(R) Xeon(R) CPU E5-2680 v4 @ 2.40GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-6.0.1 (ORCJIT, broadwell)
Environment:
  JULIA_NUM_THREADS = 28

[scottstanie]

Just adding to this- I can get PyPlot to work by doing the conda install version with ENV["PYTHON"] = "" ]build PyCall, then using PyPlot, but if i try to build PyCall with my virtualenv python, I always get the infinite loop error.

Is there a way to use PyPlot with a virtualenv python, and not the conda one?

[scottstanie]

A workaround for me I found-

plt = pyimport("matplotlib.pyplot")
x = range(0;stop=2*pi,length=1000); y = sin.(3*x + 4*cos.(2*x));
plt.plot(x, y, color="red", linewidth=2.0, linestyle="--")
plt.show()

even though PyCall recommends not doing this, it works and throws no error, while PyPlot continues to give errors with any virtualenv of python versions 3.4-3.7

[stevengj]

tcl::Bgerror sounds like a problem with the tcl (tkagg) backend. Can you try another backend?

e.g.

julia> ENV["MPLBACKEND"]="qt5agg"

julia> using PyPlot

[scottstanie]

Thank you @stevengj ! Is the easiest way to make this the default just adding export MPLBACKEND=qt5agg to my .bashrc? Or is there another way to configure it?

[stevengj]

You can configure it by creating a .matplotlibrc file with a line backend: Qt5Agg. Google "matplotlibrc" for more info.

The tcl backend is already broken on MacOS (#410) due to an upstream bug — it's concerning to hear that it may be broken on Linux too. Maybe I should just make qt5agg the default everywhere.

[jacob-roth]

I ave a similar issue. From a fresh REPL:

julia> versioninfo()
Julia Version 1.7.3
Commit 742b9abb4d (2022-05-06 12:58 UTC)
Platform Info:
  OS: macOS (x86_64-apple-darwin21.4.0)
  CPU: Intel(R) Core(TM) i7-7820HQ CPU @ 2.90GHz
  WORD_SIZE: 64
  LIBM: libopenlibm
  LLVM: libLLVM-12.0.1 (ORCJIT, skylake)
Environment:
  JULIA_BINDIR = /Applications/Julia-1.7.app/Contents/Resources/julia/bin/

julia> ENV["PYTHON"] = "/Library/Frameworks/Python.framework/Versions/3.9/bin/python3"
"/Library/Frameworks/Python.framework/Versions/3.9/bin/python3"

julia> ENV["MPLBACKEND"]="qt5agg"
"qt5agg"

(@v1.7) pkg> add PyPlot
    Updating registry at `~/.julia/registries/General.toml`
   Resolving package versions...
  No Changes to `~/.julia/environments/v1.7/Project.toml`
  No Changes to `~/.julia/environments/v1.7/Manifest.toml`

(@v1.7) pkg> build PyPlot PyCall
    Building Conda ─→ `~/.julia/scratchspaces/44cfe95a-1eb2-52ea-b672-e2afdf69b78f/6e47d11ea2776bc5627421d59cdcc1296c058071/build.log`
    Building PyCall → `~/.julia/scratchspaces/44cfe95a-1eb2-52ea-b672-e2afdf69b78f/1fc929f47d7c151c839c5fc1375929766fb8edcc/build.log`

julia> using PyPlot
┌ Warning: PyPlot is using tkagg backend, which is known to cause crashes on MacOS (#410); use the MPLBACKEND environment variable to request a different backend.
└ @ PyPlot ~/.julia/packages/PyPlot/XaELc/src/init.jl:198