Allow predicates in plugin and middleware lists

See clojure-emacs/clj-refactor.el#392 (comment)

CHANGELOG.md

@@ -16,6 +16,7 @@
 * [#2191](https://github.com/clojure-emacs/cider/issues/2191): Add support for jacking-in just with the `clojure` command-line tool and `tools.deps`.
 * Make it possible to start a Nashorn ClojureScript REPL.
 * [#2235](https://github.com/clojure-emacs/cider/pull/2235): Make the REPL ignore blank input rather than evaluating.
+* [#2238](https://github.com/clojure-emacs/cider/pull/2238): Allow specifying predicates for entries in `cider-jack-in-lein-plugins` and `cider-jack-in-nrepl-middlewares`.
 
 ### Bugs Fixed
 

cider.el

@@ -358,17 +358,60 @@ specifying the artifact ID, and the second element the version number."
                        (string :tag "Version"))))
 
 (defvar cider-jack-in-lein-plugins nil
-  "List of Leiningen plugins where elements are lists of artifact name and version.")
+  "List of Leiningen plugins to be injected at jack-in.
+Each element is a list of artifact name and version, followed optionally by
+keyword arguments.  The only keyword argument currently accepted is
+`:predicate', which should be given a function that takes the list (name,
+version, and keyword arguments) and returns non-nil to indicate that the
+plugin should actually be injected.  (This is useful primarily for packages
+that extend CIDER, not for users.  For example, a refactoring package might
+want to inject some middleware only when within a project context.)")
 (put 'cider-jack-in-lein-plugins 'risky-local-variable t)
 (cider-add-to-alist 'cider-jack-in-lein-plugins
                     "cider/cider-nrepl" (upcase cider-version))
 
+(defun cider-jack-in-normalized-lein-plugins ()
+  "Return a normalized list of Leiningen plugins to be injected.
+See `cider-jack-in-lein-plugins' for the format, except that the list
+returned by this function does not include keyword arguments."
+  (thread-last cider-jack-in-lein-plugins
+    (seq-filter
+     (lambda (spec)
+       (if-let* ((pred (plist-get (seq-drop spec 2) :predicate)))
+           (funcall pred spec)
+         t)))
+    (mapcar
+     (lambda (spec)
+       (seq-take spec 2)))))
+
 (defvar cider-jack-in-nrepl-middlewares nil
   "List of Clojure variable names.
-Each of these Clojure variables should hold a vector of nREPL middlewares.")
+Each of these Clojure variables should hold a vector of nREPL middlewares.
+Instead of a string, an element can be a list containing a string followed
+by optional keyword arguments.  The only keyword argument currently
+accepted is `:predicate', which should be given a function that takes the
+list (string and keyword arguments) and returns non-nil to indicate that
+the middlewares should actually be injected.")
 (put 'cider-jack-in-nrepl-middlewares 'risky-local-variable t)
 (add-to-list 'cider-jack-in-nrepl-middlewares "cider.nrepl/cider-middleware")
 
+(defun cider-jack-in-normalized-nrepl-middlewares ()
+  "Return a normalized list of middleware variable names.
+See `cider-jack-in-nrepl-middlewares' for the format, except that the list
+returned by this function only contains strings."
+  (thread-last cider-jack-in-nrepl-middlewares
+    (seq-filter
+     (lambda (spec)
+       (or (not (listp spec))
+           (if-let* ((pred (plist-get (cdr spec) :predicate)))
+               (funcall pred spec)
+             t))))
+    (mapcar
+     (lambda (spec)
+       (if (listp spec)
+           (car spec)
+         spec)))))
+
 (defun cider--list-as-boot-artifact (list)
   "Return a boot artifact string described by the elements of LIST.
 LIST should have the form (ARTIFACT-NAME ARTIFACT-VERSION).  The returned
@@ -483,14 +526,14 @@ dependencies."
              (cider-add-clojure-dependencies-maybe
               cider-jack-in-dependencies)
              cider-jack-in-dependencies-exclusions
-             cider-jack-in-lein-plugins))
+             (cider-jack-in-normalized-lein-plugins)))
     ("boot" (cider-boot-jack-in-dependencies
              global-opts
              params
              (cider-add-clojure-dependencies-maybe
               cider-jack-in-dependencies)
-             cider-jack-in-lein-plugins
-             cider-jack-in-nrepl-middlewares))
+             (cider-jack-in-normalized-lein-plugins)
+             (cider-jack-in-normalized-nrepl-middlewares)))
     ("clojure" (cider-clojure-jack-in-dependencies
                 global-opts
                 params

test/cider-tests.el

@@ -134,7 +134,62 @@
                 :to-equal "-C -o -i \"(require 'cider.tasks)\" -d org.clojure/tools.nrepl\\:0.2.12 -d cider/cider-nrepl\\:0.11.0 cider.tasks/add-middleware -m cider.nrepl/cider-middleware repl -s wait"))
     (it "can concat in a gradle project"
         (expect (cider-inject-jack-in-dependencies "-m" "--no-daemon clojureRepl" "gradle")
-                :to-equal "-m --no-daemon clojureRepl"))))
+                :to-equal "-m --no-daemon clojureRepl")))
+
+  (describe "when there are predicates"
+    :var (plugins-predicate middlewares-predicate)
+
+    (before-each
+      (fset 'plugins-predicate (lambda (&rest _) t))
+      (fset 'middlewares-predicate (lambda (&rest _) t))
+      (setq-local cider-jack-in-lein-plugins '(("refactor-nrepl" "2.0.0" :predicate plugins-predicate) ("cider/cider-nrepl" "0.11.0")))
+      (setq-local cider-jack-in-nrepl-middlewares '(("refactor-nrepl.middleware/wrap-refactor" :predicate middlewares-predicate) "cider.nrepl/cider-middleware" ("another/middleware"))))
+    (it "includes plugins whose predicates return true"
+      (expect (cider-jack-in-normalized-lein-plugins)
+              :to-equal '(("refactor-nrepl" "2.0.0") ("cider/cider-nrepl" "0.11.0"))))
+    (it "includes middlewares whose predicates return true"
+      (expect (cider-jack-in-normalized-nrepl-middlewares)
+              :to-equal '("refactor-nrepl.middleware/wrap-refactor" "cider.nrepl/cider-middleware" "another/middleware")))
+    (it "ignores plugins whose predicates return false"
+      (spy-on 'plugins-predicate :and-return-value nil)
+      (expect (cider-jack-in-normalized-lein-plugins)
+              :to-equal '(("cider/cider-nrepl" "0.11.0"))))
+    (it "ignores plugins whose predicates return false"
+      (spy-on 'middlewares-predicate :and-return-value nil)
+      (expect (cider-jack-in-normalized-nrepl-middlewares)
+              :to-equal '("cider.nrepl/cider-middleware" "another/middleware")))
+    (it "calls plugin predicates with the whole list entry"
+      (spy-on 'plugins-predicate)
+      (cider-jack-in-normalized-lein-plugins)
+      (expect 'plugins-predicate
+              :to-have-been-called-with '("refactor-nrepl" "2.0.0" :predicate plugins-predicate)))
+    (it "calls middleware predicates with the whole list entry"
+      (spy-on 'middlewares-predicate)
+      (cider-jack-in-normalized-nrepl-middlewares)
+      (expect 'middlewares-predicate
+              :to-have-been-called-with '("refactor-nrepl.middleware/wrap-refactor" :predicate middlewares-predicate)))
+    (it "only calls plugin predicates for their own entries"
+      (spy-on 'plugins-predicate)
+      (cider-jack-in-normalized-lein-plugins)
+      (expect 'plugins-predicate :to-have-been-called-times 1))
+    (it "only calls middleware predicates for their own entries"
+      (spy-on 'middlewares-predicate)
+      (cider-jack-in-normalized-nrepl-middlewares)
+      (expect 'middlewares-predicate :to-have-been-called-times 1)))
+
+  (describe "when the middleware and plugin lists have been normalized"
+    (before-each
+      (spy-on 'cider-jack-in-normalized-nrepl-middlewares
+              :and-return-value '("refactor-nrepl.middleware/wrap-refactor" "cider.nrepl/cider-middleware"))
+      (spy-on 'cider-jack-in-normalized-lein-plugins
+              :and-return-value '(("refactor-nrepl" "2.0.0") ("cider/cider-nrepl" "0.11.0")))
+      (setq-local cider-jack-in-dependencies-exclusions '()))
+    (it "uses them in a lein project"
+      (expect (cider-inject-jack-in-dependencies "" "repl :headless" "lein")
+              :to-equal "update-in :dependencies conj \\[org.clojure/tools.nrepl\\ \\\"0.2.12\\\"\\] -- update-in :plugins conj \\[refactor-nrepl\\ \\\"2.0.0\\\"\\] -- update-in :plugins conj \\[cider/cider-nrepl\\ \\\"0.11.0\\\"\\] -- repl :headless"))
+    (it "uses them in a boot project"
+      (expect (cider-inject-jack-in-dependencies "" "repl -s wait" "boot")
+              :to-equal "-i \"(require 'cider.tasks)\" -d org.clojure/tools.nrepl\\:0.2.12 -d refactor-nrepl\\:2.0.0 -d cider/cider-nrepl\\:0.11.0 cider.tasks/add-middleware -m refactor-nrepl.middleware/wrap-refactor -m cider.nrepl/cider-middleware repl -s wait"))))
 
 (describe "cider-jack-in-auto-inject-clojure"
   (it "injects `cider-minimum-clojure-version' when `cider-jack-in-auto-inject-clojure' is set to minimal"