projectile-compile-project: Symbol's function definition is void: projectile-go-function

[benma]

Likely introduced by c2785d636804cd23b90eec4388cf4e5624f5e003.

Expected behavior

No error, the prompt for the compilation command should appear.

Actual behavior

Error.

Steps to reproduce the problem

Call M-x projectile-compile-project.

Projectile version information

Projectile version: 20160723.622

Emacs version

$ emacs-snapshot --version
GNU Emacs 25.0.50.1

Operating system

Ubuntu 14.04

[jcf]

Same with projectile-find-test-file, and projectile-toggle-between-implementation-and-test.

Trashing ~/.emacs.d/elpa and/or wiping out *.elc files does not help.

[tomjakubowski]

For my fellow hapless users stumbling on this issue: a simple workaround is to evaluate this:

(fset 'projectile-go-function 'projectile-go)

I don't feel like touching my .emacs.d for this, so I just type that into the *scratch* buffer and evaluate it with C-M-x when I start emacs (which is pretty infrequently!)

[bbatsov]

I can't immediately figure out what went wrong. The defcustom is supposed to be a function. @malabarba any idea what have I messed up?

[Malabarba]

I think you shouldn't be quoting projectile-go-function on this line: https://github.com/bbatsov/projectile/commit/c2785d636804cd23b90eec4388cf4e5624f5e003#diff-e350afa47840c07f4dbf92840e4f8cfaR1874

The way it's now the symbol is getting called as a function, instead of its variable value being called.

[bbatsov]

Ops. You're absolutely right. Silly me. :-)

[Malabarba]

:)

[DesmondHayes]

Now projectile doesn't load at all.
Updated to the latest projectile 20160727.748 from melpa.

Compiling file /home/desmondhayes/.emacs.d/elpa/projectile-20160727.748/projectile.el at Wed Jul 27 20:28:49 2016
projectile.el:1875:39:Warning: reference to free variable
    `projectile-go-function'

[joonro]

Me too - I'm getting

Symbol's value as variable is void: projectile-go-function

[jethrosun]

Same here, likely Emacs will complain variable is void every time you try to initialize it.

[bitwalker]

Looks like the issue is that the line should be:

(projectile-register-project-type 'go #'projectile-go-function "go build ./..." "go test ./...")

Instead of:

(projectile-register-project-type 'go projectile-go-function "go build ./..." "go test ./...")

Making that change fixes it for me.

[kaushalmodi]

@bitwalker It was anyways quoted earlier and this 'fix' commit broke it.
~I do not use projectile-go-function, but just quoting it back fixed the problem for me too.~

Actually the correct fix is to simply move the projective-go-function defcustom form before the first use of the projectile-go-function variable in the (projectile-register-project-type 'go projectile-go-function "go build ./..." "go test ./...") line.

I now have this and it works:

(defcustom projectile-go-function 'projectile-go
  "Function to determine if project's type is go."
  :group 'projectile
  :type 'function)

(projectile-register-project-type 'emacs-cask '("Cask") "cask install")
;; snip
(projectile-register-project-type 'go projectile-go-function "go build ./..." "go test ./...")

[bitwalker]

@kaushalmodi I just changed it to work the same way as projectile-cabal, projectile-go-function was only quoted earlier, not sharp-quoted, at least since I popped into this thread. Anyhow, your fix looks like it works as well, just a different approach.

[etanzapinsky]

@bitwalker when trying to compile locally I think there's a difference between a defun function and a defcustom variable where you can #' the defun function later on but not the defcustom variable. I had the #' fix in a pull request, but couldn't get the tests to pass when running make test and @kaushalmodi 's suggestion works.

[kaushalmodi]

@bitwalker

I just changed it to work the same way as projectile-cabal

I use neither cabal nor go, but looking at the code, there's a major difference between projectile-cabal and projectile-go-function ..

• The second arg of projectile-register-project-type expects "marker files". These could either be a direct list of files, or a function that returns such a list, or a variable that holds a function name that returns that list.
• Now projectile-cabal is a function that returns such a list, so it is hash-quoted.
• But projectile-go-function is a variable that holds the function name projectile-go and projectile-go is a function that returns the marker files list. So projectile-go-function, being just a variable (and not a function) must not be hash-quoted.
  More on that: The reason is that (hash)quoting a symbol prevents evaluation of that symbol. If you have (setq foo "bar"), 'foo will return just 'foo because it is quoted. But foo will return "bar". As we first need to evaluate projectile-go-function so that we get the function name it holds (projectile-go), it must not be quoted.
• Also as that is a variable, it needs to be 'declared' using defcustom or defvar or something before it is used for the first time. So that defcustom has to be moved above the point of its first use.

[bitwalker]

@kaushalmodi makes sense now that you've explained it :) thanks!

[ryukinix]

I still experience that on version 20200810.544...