canvas.line freezes indefinitely with numba 0.51.1

ALL software version info

python 3.8 numba 0.51.1 datashader 0.11.1 bokeh 2.2.0 numpy 1.19.1

Description of expected behavior and the observed behavior

Observed behavior: canvas.line function freezes indefinitely

Complete, minimal, self-contained example code that reproduces the issue

# code goes here between backticks
import datetime
import pandas as pd
import numpy as np
import xarray as xr
import datashader as ds
import datashader.transfer_functions as tf
from collections import OrderedDict
# Constants
np.random.seed(2)
n = 100000                               # Number of points
cols = list('abcdefg')                   # Column names of samples
start = datetime.datetime(2010, 10, 1, 0)   # Start time
# Generate a fake signal
signal = np.random.normal(0, 0.3, size=n).cumsum() + 50
# Generate many noisy samples from the signal
noise = lambda var, bias, n: np.random.normal(bias, var, n)
data = {c: signal + noise(1, 10*(np.random.random() - 0.5), n) for c in cols}
# Add some "rogue lines" that differ from the rest 
cols += ['x'] ; data['x'] = signal + np.random.normal(0, 0.02, size=n).cumsum() # Gradually diverges
cols += ['y'] ; data['y'] = signal + noise(1, 20*(np.random.random() - 0.5), n) # Much noisier
cols += ['z'] ; data['z'] = signal # No noise at all
# Pick a few samples from the first line and really blow them out
locs = np.random.choice(n, 10)
data['a'][locs] *= 2
# Create a dataframe
data['Time'] = [start + datetime.timedelta(minutes=1)*i for i in range(n)]
df = pd.DataFrame(data)
df['ITime'] = pd.to_datetime(df['Time']).astype('int64')
# Default plot ranges:
x_range = (df.iloc[0].ITime, df.iloc[-1].ITime)
y_range = (1.2*signal.min(), 1.2*signal.max())
print("x_range: {0} y_range: {1}".format(x_range,y_range))
cvs = ds.Canvas(x_range=x_range, y_range=y_range, plot_height=300, plot_width=900)
aggs= OrderedDict((c, cvs.line(df, 'ITime', c)) for c in cols)
img = tf.shade(aggs['a'])

cc @philippjfr

[AjayThorve]

can confirm this is now fixed with numba 0.51.2, @gmarkall thanks for the quick fix.

but I don’t know that it’s doing the right thing because the reproducer produces no output. Is there a way I can check that Datashader is working properly with Numba 0.51.1 + the patch? the final img output should be something like this (which it now is)

[quasiben]

After digging for a bit it might have something to do with https://github.com/numba/numba/pull/6146