I have been using Clojure, ClojureScript, lein, shadow-cljs, re-frame, reagent, Emacs, and CIDER to work on a Clojure/ClojureScript dynamic web app project.
Usually, I build the project by executing shadow-cljs watch app. It works fine. I can use the application and watch changes.
Currently, I am working on a Continuous Integration project via GitHub Actions. In this new environment, I wanna use a different command: shadow-cljs compile app.
But, I am having problems. Both on GitHub Actions env and in my local env (which is reproducing the steps on GitHub Actions).
The result returned by the command is quite weird. First, it says the compilation went well, Build completed, and the terminal displays some non-harmful warnings:
shadow-cljs compile app
shadow-cljs - config: /Users/pedro/projects/my_project/shadow-cljs.edn
WARNING: random-uuid already refers to: #'clojure.core/random-uuid in namespace: portal.runtime.browser, being replaced by: #'portal.runtime.browser/random-uuid
[:app] Compiling ...
SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
SLF4J: Defaulting to no-operation (NOP) logger implementation
SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
WARNING: abs already refers to: #'clojure.core/abs in namespace: day8.re-frame-10x.inlined-deps.garden.v1v3v10.garden.color, being replaced by: #'day8.re-frame-10x.inlined-deps.garden.v1v3v10.garden.color/abs
WARNING: abs already refers to: #'clojure.core/abs in namespace: garden.color, being replaced by: #'garden.color/abs
[:app] Build completed. (1121 files, 27 compiled, 8 warnings, 45.85s)
------ WARNING #1 - :redef -----------------------------------------------------
(... omitted ...)
Unfortunately, the terminal stays like this forever. It behaves like the watch command... But, compile is not supposed to be like this.
The terminal does not finish the process. There is no exit. Even though the build is complete, as stated in the last line before WARNING.
Feels like a deadlock situation. The terminal is still responsive because I can cancel the process with Control-c. But, besides canceling it, it is frozen. This can be catastrophic on GitHub actions since you are going to be paying for an ongoing process.
On shadow-clj.edn, I tried commenting out compilation-options:
;:compiler-options {:optimizations :none}
But it did not make any difference. The same problem happens with shadow-cljs release app.
After finding a GitHub issue with a similar problem, I also tried:
:js-options {:resolve {"highlight.js" {:target :npm :require "highlight.js/lib/core"}}}
One of my hypotheses is that highlight.js is causing some trouble while parsing strings and/or files...
I am also afraid the problem could be some REPL being fired up by some dependency and blocking the process for the exit... But I am not sure where to look for it.
Why is this happening? What could be causing this? How can I solve it?
;;;;
UPDATE:
After @thomasheller kind answer, I tried some things. I believe all of the hints can be discarded for the present situation, except for the macros:
1 - The project does not use user.clj
2 - Build hooks is the default setting which is basically a comment:
:build-hooks [;; this will create a build report for every release build
;; which includes a detailed breakdown of the included sources
;; and how much they each contributed to the overall size:
#_(shadow.cljs.build-report/hook
{:output-to "build-reports/report.html"})]
3- There is no shadow-cljs start, server, or watch process going before trying to compile. The problem of an endless compile app happens just after re-starting my MacBook, on the CI, in others' people's PC... So, it is unrelated.
Ok. Now, let's talk about the macros... The project's main repository has 6 defmacros - according to a git grep (I have not checked the dependencies).
I am suspicious about one of the macros which is involved in reading files:
(defmacro slurp [file & [default]]
(if (.exists (io/file file))
(clojure.core/slurp file)
default))
Why does this exist? Well, it is being used inside another macro that reads config files related to environment variables:
(defmacro read-open-config [env-var]
(clojure.edn/read-string (slurp (str "config/" (System/getenv env-var) "-open.edn"))))
We have multiple config files for different purposes (I know it is not the standard practice...).
It feels like too much dynamicity...
After a long research process, it was discovered that the problem came from tests inside a private dependency. Apparently, some tests with asynchronous processes profile were holding the compilation process from finishing.
After commenting-out some olds tests, the compilation happened as expected.