bug#71200: TRAMP: Trying to do a project-find-file or (find-directory) using the podman method causes a (wrong-type-argument stringp nil) error

[alexis purslane]

As the the title says, whenever I try to do project-find-* on a project that 
uses the podman TRAMP method, it spits out an error and otherwise does nothing. 
Here's the backtrace:

```
Debugger entered--Lisp error: (wrong-type-argument stringp nil)
  split-string(nil "\0" t)
  project--vc-list-files("/podman:development:~/Development/embryo-engine/" Git 
nil)
  #f(compiled-function (dir) #<bytecode 
-0x443eb4e00f15eb4>)("/podman:development:~/Development/embryo-engine/")
  mapcan(#f(compiled-function (dir) #<bytecode -0x443eb4e00f15eb4>) 
("/podman:development:~/Development/embryo-engine/"))
  #f(compiled-function (project &optional dirs) #<bytecode 
0xe73db4877a27b8>)((vc Git "/podman:development:~/Development/embryo-engine/") 
("/podman:development:~/Development/embryo-engine/"))
  apply(#f(compiled-function (project &optional dirs) #<bytecode 
0xe73db4877a27b8>) (vc Git "/podman:development:~/Development/embryo-engine/") 
("/podman:development:~/Development/embryo-engine/"))
  project-files((vc Git "/podman:development:~/Development/embryo-engine/") 
("/podman:development:~/Development/embryo-engine/"))
  project-find-file-in(nil ("/podman:development:~/Development/embryo-engine/") 
(vc Git "/podman:development:~/Development/embryo-engine/") nil)
  project-find-file()
  #<subr 
F616e6f6e796d6f75732d6c616d626461_anonymous_lambda_62>("/podman:development:~/Development/embryo-engine/")
  funcall(#<subr F616e6f6e796d6f75732d6c616d626461_anonymous_lambda_62> 
"/podman:development:~/Development/embryo-engine/")
  (lambda (&rest _) (funcall (dashboard-projects-backend-switch-function) 
(dashboard-expand-path-alist 
"0|/podman:development:~/Development/embryo-engine/" 
dashboard-projects-alist)))((item :tag #(" 
/podman:development:~/Development/embryo-engine/" 0 1 (rear-nonsticky t display 
(raise 0.01) font-lock-face (:family "Symbols Nerd Font Mono" :height 1.0) face 
(:family "Symbols Nerd Font Mono" :height 1.0))) :action (lambda (&rest _) 
(funcall (dashboard-projects-backend-switch-function) 
(dashboard-expand-path-alist 
"0|/podman:development:~/Development/embryo-engine/" 
dashboard-projects-alist))) :button-face dashboard-items-face :mouse-face 
highlight :button-prefix "" :button-suffix "" :format "%[%t%]" :button-overlay 
#<overlay from 706 to 756 in *dashboard*> :from #<marker (moves after 
insertion) at 706 in *dashboard*> :to #<marker at 756 in *dashboard*>) nil)
  widget-apply-action((item :tag #(" 
/podman:development:~/Development/embryo-engine/" 0 1 (rear-nonsticky t display 
(raise 0.01) font-lock-face (:family "Symbols Nerd Font Mono" :height 1.0) face 
(:family "Symbols Nerd Font Mono" :height 1.0))) :action (lambda (&rest _) 
(funcall (dashboard-projects-backend-switch-function) 
(dashboard-expand-path-alist 
"0|/podman:development:~/Development/embryo-engine/" 
dashboard-projects-alist))) :button-face dashboard-items-face :mouse-face 
highlight :button-prefix "" :button-suffix "" :format "%[%t%]" :button-overlay 
#<overlay from 706 to 756 in *dashboard*> :from #<marker (moves after 
insertion) at 706 in *dashboard*> :to #<marker at 756 in *dashboard*>) nil)
  widget-button-press(706)
  evil-ret-gen(nil nil)
  evil-ret(nil)
  funcall-interactively(evil-ret nil)
  command-execute(evil-ret)
```

I have a weird little snippet of code to fix it, and a sort-of analysis of what 
I think is wrong, here: 
https://gist.github.com/alexispurslane/890ea9971787c979f8c59c8decf132c4. 
However, this fix is half-baked currently.

Here's my emacs info:

```
Basic Info: 

GNU Emacs 29.3 (build 1, x86_64-redhat-linux-gnu, GTK+ Version
3.24.41, cairo version 1.18.0) of 2024-04-25

Build Flags:
"--build=x86_64-redhat-linux-gnu --host=x86_64-redhat-linux-gnu 
--program-prefix= --disable-dependency-tracking --prefix=/usr 
--exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc 
--datadir=/usr/share --includedir=/usr/include --libdir=/usr/lib64 
--libexecdir=/usr/libexec --localstatedir=/var --runstatedir=/run 
--sharedstatedir=/var/lib --mandir=/usr/share/man --infodir=/usr/share/info 
--with-cairo --with-dbus --with-gif --with-gpm=no --with-harfbuzz --with-jpeg 
--with-json --with-modules --with-native-compilation=aot --with-pgtk --with-png 
--with-rsvg --with-sqlite3 --with-tiff --with-tree-sitter --with-webp 
--with-xpm --with-xwidgets build_alias=x86_64-redhat-linux-gnu 
host_alias=x86_64-redhat-linux-gnu CC=gcc 'CFLAGS=-DMAIL_USE_LOCKF -O2 
-flto=auto -ffat-lto-objects -fexceptions -g -grecord-gcc-switches -pipe -Wall 
-Werror=format-security -Wp,-U_FORTIFY_SOURCE,-D_FORTIFY_SOURCE=3 
-Wp,-D_GLIBCXX_ASSERTIONS -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 
-fstack-protector-strong -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64 
-march=x86-64 -mtune=generic -fasynchronous-unwind-tables 
-fstack-clash-protection -fcf-protection -fno-omit-frame-pointer 
-mno-omit-leaf-frame-pointer ' LDFLAGS=-Wl,-z,relro 
PKG_CONFIG_PATH=:/usr/lib64/pkgconfig:/usr/share/pkgconfig CXX=g++ 
'CXXFLAGS=-O2 -flto=auto -ffat-lto-objects -fexceptions -g 
-grecord-gcc-switches -pipe -Wall -Werror=format-security 
-Wp,-U_FORTIFY_SOURCE,-D_FORTIFY_SOURCE=3 -Wp,-D_GLIBCXX_ASSERTIONS 
-specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -fstack-protector-strong 
-specs=/usr/lib/rpm/redhat/redhat-annobin-cc1  -m64 -march=x86-64 
-mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection 
-fcf-protection -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer '"
```

This seems like it is probably a bug, and not just user error, so I hope this 
helps.

Don't hesitate to let me know if you need more info.

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