pygmt.config doesn't work with values that have whitespaces

[seisman]

Description of the problem

Some GMT defaults can accept values that have whitespaces. For example, FORMAT_TIME_STAMP's default value is %Y %b %d %H:%M:%S.

See the example below. pygmt.config doesn't work with values that contain whitespaces. We need to do some work like #1487.

Minimal Complete Verifiable Example

import pygmt

fig = pygmt.Figure()
with pygmt.config(FORMAT_TIME_STAMP="%Y %b %d %H:%M:%S"):
    fig.basemap(region=[0, 10, 0, 10], projection="X10c/10c", frame=True, timestamp=True)
fig.show()

Full error message

gmtset [ERROR]: Unrecognized keyword %b.
gmtset [WARNING]: Last GMT Defaults parameter from command options had no value
gmtset [ERROR]:  1 GMT Defaults conversion errors from command options
Traceback (most recent call last):
  File "/home/seisman/Syncthing/test.py", line 5, in <module>
    fig.basemap(region=[0, 10, 0, 10], projection="X10c/10c", frame=True, timestamp=True)
  File "/home/seisman/OSS/gmt/pygmt/pygmt/src/config.py", line 213, in __exit__
    lib.call_module(module="set", args=arg_str)
  File "/home/seisman/OSS/gmt/pygmt/pygmt/clib/session.py", line 510, in call_module
    raise GMTCLibError(
pygmt.exceptions.GMTCLibError: Module 'set' failed with status code 72:
gmtset [ERROR]: Unrecognized keyword %b.
gmtset [ERROR]:  1 GMT Defaults conversion errors from command options

System information

PyGMT information:
  version: v0.8.1.dev9+g9852724e
System information:
  python: 3.9.15 | packaged by conda-forge | (main, Nov 22 2022, 15:55:03)  [GCC 10.4.0]
  executable: /home/seisman/opt/miniconda/bin/python3.9
  machine: Linux-6.0.9-300.fc37.x86_64-x86_64-with-glibc2.36
Dependency information:
  numpy: 1.23.4
  pandas: 1.5.1
  xarray: 2022.10.0
  netCDF4: 1.6.1
  packaging: 21.3
  geopandas: None
  ghostscript: 9.56.1
GMT library information:
  binary version: 6.5.0_8b8bc2e_2023.01.01
  cores: 80
  grid layout: rows
  library path: /home/seisman/opt/GMT-master/lib64/libgmt.so
  padding: 2
  plugin dir: /home/seisman/opt/GMT-master/lib64/gmt/plugins
  share dir: /home/seisman/opt/GMT-master/share
  version: 6.5.0

[seisman]

Actually, whitespaces are allowed in pygmt.config arguments, thanks to c29e632. The issue exists when the defaults values (or the old values) of the configurations contain whitespaces.

Here is a better example:

import pygmt

fig = pygmt.Figure()
with pygmt.config(FORMAT_TIME_STAMP="%Y"):
    fig.basemap(region=[0, 10, 0, 10], projection="X10c/10c", frame=True, timestamp=True)
fig.show()

The default value of FORMAT_TIME_STAMP is %Y %b %d %H:%M:%S. When exiting the context manager, pygmt.config calls the gmtset module to reset it to the old value. That's where it fails.

The error message is:

gmtset [ERROR]: Unrecognized keyword %b.
gmtset [WARNING]: Last GMT Defaults parameter from command options had no value
gmtset [ERROR]:  1 GMT Defaults conversion errors from command options
Traceback (most recent call last):
  File "/Users/seisman/OSS/gmt/pygmt/workspace/test2.py", line 4, in <module>
    with pygmt.config(FORMAT_TIME_STAMP="%Y"):
  File "/Users/seisman/OSS/gmt/pygmt/pygmt/src/config.py", line 213, in __exit__
    lib.call_module(module="set", args=arg_str)
  File "/Users/seisman/OSS/gmt/pygmt/pygmt/clib/session.py", line 510, in call_module
    raise GMTCLibError(
pygmt.exceptions.GMTCLibError: Module 'set' failed with status code 72:
gmtset [ERROR]: Unrecognized keyword %b.
gmtset [ERROR]:  1 GMT Defaults conversion errors from command options

[seisman]

Here is another example showing the bug:

import pygmt

fig = pygmt.Figure()
pygmt.config(FORMAT_DATE_MAP="yyyy mm dd")
with pygmt.config(FORMAT_DATE_MAP="o dd"):
    fig.basemap(
        region=["1969-7-21T", "1969-7-23T", 0, 1],
        projection="X2.5c/0.1c",
        frame=["sxa1D", "S"],
    )
fig.show()

The error message is:

gmtset [ERROR]: Unrecognized keyword mm.
gmtset [ERROR]:  1 GMT Defaults conversion errors from command options
Traceback (most recent call last):
  File "/Users/seisman/OSS/gmt/pygmt/workspace/test2.py", line 5, in <module>
    with pygmt.config(FORMAT_DATE_MAP="o dd"):
  File "/Users/seisman/OSS/gmt/pygmt/pygmt/src/config.py", line 213, in __exit__
    lib.call_module(module="set", args=arg_str)
  File "/Users/seisman/OSS/gmt/pygmt/pygmt/clib/session.py", line 510, in call_module
    raise GMTCLibError(
pygmt.exceptions.GMTCLibError: Module 'set' failed with status code 72:
gmtset [ERROR]: Unrecognized keyword mm.
gmtset [ERROR]:  1 GMT Defaults conversion errors from command options

The test is modified from the existing test

pygmt/pygmt/tests/test_config.py

Line 68 in b8ac1f8

def test_config_format_date_map():

so that I can reuse this test as a regression test for this issue. The new test is added in #2331.