clojure.repl/source-fn returns nil for :local/root dependencies

Question

Environment

• Clojure 1.12.1 REPL with :local/root dependencies in deps.edn
• Example: local.lib namespace at /Users/user/projects/repo/src/local/lib.clj

History

1. Load namespace from :local/root dependency in REPL

2. Verify function metadata:

   (meta #'local.lib/some-function)
   => {:arglists ([arg]),

    :line 42,
    :column 1,
    :file "/Users/user/projects/repo/src/local/lib.clj",
    :name some-function,
    :ns #object [clojure.lang.Namespace 0x123abc "local.lib"]}
   

3. Call (clojure.repl/source-fn 'local.lib/some-function) returns nil

Expectation

source-fn should return the source code string for the symbol.

Actual

source-fn returns nil.

Evidence

(.getResourceAsStream (RT/baseLoader) "/Users/user/projects/repo/src/local/lib.clj") returns nil because RT/baseLoader cannot access local filesystem paths, only classpath JAR resources.

Impact

Breaks REPL-driven development workflow for :local/root dependencies. Creates an inconsistent experience between JAR and local dependencies.

Comments

How exactly did you "Load namespace from :local/root dependency in REPL"?

If I just eval the file via Calva into the REPL, I can't get source. If I explicitly require the ns, I can get source.

Answer 1

This works for me locally but I'm assuming things you haven't provided. What's the deps.edn of repo? what's the deps.edn/command line of the REPL? Did you (require 'local.lib)? (It is necessary to load the namespace before you call source-fn.)

• My repo deps.edn: {:paths ["src"]}

• My command line: clj -Sdeps '{:deps {local/repo {:local/root "repo"}}}'

  Clojure 1.12.1
  user=> (require 'local.lib)
  nil
  user=> (meta #'local.lib/some-function)
  {:arglists ([]), :line 3, :column 1, :file "local/lib.clj", :name some-function, :ns #object[clojure.lang.Namespace 0x14f3c6fc "local.lib"]}
  user=> (clojure.repl/source-fn 'local.lib/some-function)
  "(defn some-function [] \"hi\")"

"RT/baseLoader cannot access local filesystem paths, only classpath JAR resources." is incorrect. The file system resource path you care about here is NOT an absolute path, it is: (.getResourceAsStream (clojure.lang.RT/baseLoader) "local/lib.clj") (which is subsequently a path found via the classpath roots, which may be either in directories or jars:

user=> (:file (meta #'local.lib/some-function))
"local/lib.clj"