python-start-or-switch-repl doesn't start REPL in Emacs 25

[bmag]

Description

In Emacs 25, calling python-start-or-switch-repl (SPC m ' in Python buffers) when there's no REPL doesn't start a new REPL. In Emacs 24.5 it does start a new REPL.

A short check revealed that python-start-or-switch-repl (defined in Python layer) calls python-shell-switch-to-shell (built-in Emacs function). In Emacs 24.5, if no REPL exists then python-shell-switch-to-shell start a new REPL, but in Emacs 25 it no longer does so.

Reproduction guide 🪲

• Enable the python layer
• Start Emacs 25 (note: 25, not 24.5 or 24.4)
• Open or create a python file
• press , ' (calls python-start-or-switch-repl)

Observed behaviour: 👀 💔
Emacs doesn't open a REPL, instead prints an error message:

python-shell-get-process-or-error: No inferior Python process running.

Expected behaviour: ❤️ 😄
Emacs opens a python REPL.

System Info 💻

• OS: gnu/linux
• Emacs: 25.0.95.1
• Spacemacs: 0.105.21
• Spacemacs branch: buffer-predicate (rev. bd7225f)
• Graphic display: t
• Distribution: spacemacs
• Editing style: hybrid
• Completion: helm
• Layers:

(helm
 (auto-completion :variables auto-completion-complete-with-key-sequence "jk" auto-completion-complete-with-key-sequence-delay 0.5 auto-completion-enable-snippets-in-popup nil auto-completion-enable-help-tooltip t company-tooltip-align-annotations t)
 emacs-lisp
 (git :variables git-magit-status-fullscreen t)
 markdown org
 (shell :variables shell-default-shell 'shell shell-default-height 30 shell-default-position 'bottom)
 syntax-checking version-control
 (latex :variables latex-enable-auto-fill t latex-enable-folding t)
 pdf-tools evil-cleverparens python command-log smex themes-megapack c-c  
 (clojure :variables clojure-enable-fancify-symbols nil)
 ruby common-lisp ibuffer octave imenu-list window-purpose
 (theming :variables theming-modifications
          '((spacemacs-dark
             (aw-leading-char-face :foreground "red" :height 3.0))
            (spacemacs-light
             (aw-leading-char-face :foreground "red" :height 3.0))
            (monokai
             (aw-leading-char-face :foreground "red" :height 3.0))
            (flatland
             (aw-leading-char-face :foreground "red" :height 3.0)))))

[bmag]

Update: this is probably a duplicate of #2872

[TheBB]

Should be fixed in master.