Fix remote cider-jack-in-clj breaking with cider-enrich-classpath #…

…3567

Fixes `cider-jack-in-clj` in tramp buffers throwing:
```
Could not start nREPL server: %s (%S)
bash: /remote/path/to/cider/clojure.sh: No such file or directory\n" "exited abnormally with code 127")
```
in cases where cider is not installed in the same directory on the
remote.

To fix this, we create temporary copy of the enrich-classpath script
named `.cider__<clojure.sh|lein.sh>__<random>` on the remote before
starting the server. The possible locations of the script are, in this
order:
- tramp-tempdir (usually "/tmp")
- clojure-project-dirj
- default-directory

If the script can't be created for any reason, the server is started with
`cider-enrich-classpath` set to nil.

Note: the temporary script will remove itself after use, but stick around when
something goes wrong before the remote process is started.

cider-util.el

@@ -515,7 +515,64 @@ Any other value is just returned."
  (mapcar #'cider--deep-vector-to-list x)
  x))
 
+
+;;; Files & Directories
+(defun cider--ensure-executable (file)
+ "Try to make FILE executable if it isn't already.
+Returns FILE on success, nil on failure."
+ (with-demoted-errors "Error while trying to make file executable:\n %s"
+ (when (or (file-executable-p file)
+ (and (set-file-modes file "u+x")
+ (file-executable-p file)))
+ file)))
+
+(defconst cider--temp-name-prefix ".cider__"
+ "Prefix for marking temporary files created by cider.")
+
+(defun cider--make-temp-name (file)
+ "Generate a randomized name from FILEs basename.
+Tag it with `cider--temp-name-prefix'"
+ (make-temp-name
+ (concat cider--temp-name-prefix (file-name-nondirectory file) "__")))
+
+(defun cider--make-nearby-temp-copy (file)
+ "Create a copy of FILE in the default local or remote tempdir.
+Falls back to `clojure-project-dir' or `default-directory'.
+The copy is marked with `cider--temp-name-prefix'."
+ (let* ((default-directory (or (clojure-project-dir) default-directory))
+ (new-file (file-name-concat (temporary-file-directory)
+ (cider--make-temp-name file))))
+ (copy-file file new-file :exists-ok nil nil :keep-permissions)
+ new-file))
+
+(defun cider--inject-self-delete (bash-file)
+ "Make BASH-FILE delete itself on exit.
+Injects the self-delete script after the first line, assuming it is a
+shebang."
+ (let (;; Don't create any temporary files.
+ (remote-file-name-inhibit-locks t)
+ (remote-file-name-inhibit-auto-save-visited t)
+ (make-backup-files nil)
+ (auto-save-default nil)
+ ;; Disable version-control check
+ (vc-handled-backends nil))
+ (with-temp-buffer
+ (insert-file-contents bash-file)
+ ;; inject after the first line, assuming it is the shebang
+ (goto-char (point-min))
+ (skip-chars-forward "^\n")
+ (insert "\n")
+ (insert (format
+ "trap 'ARG=$?
+ rm -v %s
+ echo \"cider: Cleaned up temporary script after use.\"
+ exit $ARG
+ ' EXIT"
+ (file-local-name bash-file)))
+ (write-file bash-file))
+ bash-file))
 
+
 ;;; Help mode
 
 ;; Same as https://github.com/emacs-mirror/emacs/blob/86d083438dba60dc00e9e96414bf7e832720c05a/lisp/help-mode.el#L355

cider.el

@@ -411,40 +411,64 @@ without interfering with classloaders."
  :package-version '(cider . "1.2.0")
  :safe #'booleanp)
 
-(defun cider--get-enrich-classpath-lein-script ()
- "Returns the location of enrich-classpath's lein.sh wrapper script."
- (when-let ((cider-location (locate-library "cider.el" t)))
- (concat (file-name-directory cider-location)
- "lein.sh")))
-
-(defun cider--get-enrich-classpath-clojure-cli-script ()
- "Returns the location of enrich-classpath's clojure.sh wrapper script."
- (when-let ((cider-location (locate-library "cider.el" t)))
- (concat (file-name-directory cider-location)
- "clojure.sh")))
+(defvar cider--enrich-classpath-script-names
+ '((lein . "lein.sh")
+ (clojure-cli . "clojure.sh")))
+
+(defun cider--enriched-cmd-p (cmd)
+ "Test if the shell-quoted CMD contains the name of an enrich-classpath script.
+Returns the local path to the script or nil."
+ (let* ((script-names (map-values cider--enrich-classpath-script-names))
+ (temp-prefix cider--temp-name-prefix)
+ (any-name (rx-to-string
+ `(or (: (or bos "/") (or ,@script-names) (or eos space))
+ (: ,temp-prefix (or ,@script-names)))))
+ (script (thread-last
+ (split-string-shell-command cmd)
+ (seq-filter (lambda (part) (string-match any-name part)))
+ (seq-first))))
+ (when script
+ (shell-quote-argument script))))
+
+(defun cider--get-enrich-classpath-script (project-type)
+ "Get or create an executable enrich-classpath script for PROJECT-TYPE.
+If `default-directory' is remote, create a copy at
+'<remote-tempdir>/.cider__<script-name>__<random>' that deletes itself after
+use. The search for '<remote-tempdir>' is handled by tramp and falls back to
+`clojure-project-dir' or `default-directory'. Returns nil if anything goes wrong."
+ (when-let* ((cider-dir (file-name-directory (locate-library "cider.el" t)))
+ (name (map-elt cider--enrich-classpath-script-names project-type))
+ (location (concat cider-dir name))
+ (script (cider--ensure-executable location)))
+ (if (file-remote-p default-directory)
+ (with-demoted-errors
+ "cider: Failed to initialize enrich-classpath on remote."
+ (thread-first
+ (cider--make-nearby-temp-copy script)
+ (cider--ensure-executable)
+ (cider--inject-self-delete)))
+ script)))
+
+(defun cider--jack-in-resolve-command-enrich (project-type)
+ "Conditionally wrap the command for PROJECT-TYPE with an enrich-classpath script.
+Resolves to the non-wrapped `cider-jack-in-command' if `cider-enrich-classpath' is nil or the
+ wrapper-script can't be initialized."
+ (when-let ((command (cider--resolve-command (cider-jack-in-command project-type))))
+ (if-let ((wrapper-script (and cider-enrich-classpath
+ (not (eq system-type 'windows-nt))
+ (cider--get-enrich-classpath-script project-type))))
+ (concat "bash "
+ (shell-quote-argument (file-local-name wrapper-script)) " "
+ command)
+ command)))
 
 (defun cider-jack-in-resolve-command (project-type)
  "Determine the resolved file path to `cider-jack-in-command'.
 Throws an error if PROJECT-TYPE is unknown."
  (pcase project-type
- ('lein (let ((r (cider--resolve-command cider-lein-command)))
- (if (and cider-enrich-classpath
- (not (eq system-type 'windows-nt))
- (executable-find (cider--get-enrich-classpath-lein-script)))
- (concat "bash " ;; don't assume lein.sh is executable - MELPA might change that
- (cider--get-enrich-classpath-lein-script)
- " "
- r)
- r)))
+ ('lein (cider--jack-in-resolve-command-enrich 'lein))
  ('boot (cider--resolve-command cider-boot-command))
- ('clojure-cli (if (and cider-enrich-classpath
- (not (eq system-type 'windows-nt))
- (executable-find (cider--get-enrich-classpath-clojure-cli-script)))
- (concat "bash " ;; don't assume clojure.sh is executable - MELPA might change that
- (cider--get-enrich-classpath-clojure-cli-script)
- " "
- (cider--resolve-command cider-clojure-cli-command))
- (cider--resolve-command cider-clojure-cli-command)))
+ ('clojure-cli (cider--jack-in-resolve-command-enrich 'clojure-cli))
  ('babashka (cider--resolve-command cider-babashka-command))
  ;; here we have to account for the possibility that the command is either
  ;; "npx shadow-cljs" or just "shadow-cljs"
@@ -1661,7 +1685,11 @@ PARAMS is a plist with the following keys (non-exhaustive list)
  (command-resolved (cider-jack-in-resolve-command project-type))
  ;; TODO: global-options are deprecated and should be removed in CIDER 2.0
  (command-global-opts (cider-jack-in-global-options project-type))
- (command-params (cider-jack-in-params project-type)))
+ (command-params (cider-jack-in-params project-type))
+ ;; ignore `cider-enrich-classpath' if the jack-in-command does not include
+ ;; the necessary wrapper script at this point
+ (cider-enrich-classpath (and cider-enrich-classpath
+ (cider--enriched-cmd-p command-resolved))))
  (if command-resolved
  (with-current-buffer (or (plist-get params :--context-buffer)
  (current-buffer))
@@ -2114,13 +2142,11 @@ M-2 \\[cider-jack-in-universal]."
  (cider-jack-in-clj arg))))
 
 
-;; TODO: Implement a check for command presence over tramp
 (defun cider--resolve-command (command)
- "Find COMMAND in exec path (see variable `exec-path').
-Return nil if not found. In case `default-directory' is non-local we
-assume the command is available."
- (when-let* ((command (or (and (file-remote-p default-directory) command)
- (executable-find command)
+ "Test if COMMAND exists, is executable and shell-quote it.
+Return nil otherwise. When `default-directory' is remote, the check is
+performed by tramp."
+ (when-let* ((command (or (executable-find command :remote)
  (executable-find (concat command ".bat")))))
  (shell-quote-argument command)))
 

test/cider-tests.el

@@ -106,6 +106,37 @@
  :and-return-value '())
  (expect (cider-project-type) :to-equal cider-jack-in-default))))
 
+(describe "cider--enriched-cmd-p"
+ (describe "when cmd does not contain the path to an enrich-classpath script"
+ (it "returns nil"
+ (expect (cider--enriched-cmd-p "/usr/bin/lein")
+ :to-equal nil)
+ (expect (cider--enriched-cmd-p "bash /usr/bin/lein")
+ :to-equal nil)))
+ (describe "for different path + script-name combinations"
+ :var* ((paths `("/simple/path/"
+ ,(shell-quote-argument "/tmp/path/ with spaces/")
+ ,(shell-quote-argument "/ssh:!slightly@cra --zy!path #enrich me/")))
+ (simple-names (map-values cider--enrich-classpath-script-names))
+ (tmp-names (mapcar (lambda (s) (cider--make-temp-name s)) simple-names))
+ (all-names (seq-concatenate 'list simple-names tmp-names)))
+ (cl-loop
+ for path in paths do
+ (cl-loop
+ for name in all-names do
+ (describe (format "cider--enriched-cmd-p with script: %s" (concat path name))
+ :var ((script (concat path name)))
+ (it "returns the script path in basic cases "
+ (expect (cider--enriched-cmd-p (concat "bash " script " /usr/bin/lein"))
+ :to-equal script)
+ (expect (cider--enriched-cmd-p (concat "TEST=1 bash " script " /usr/bin/env lein"))
+ :to-equal script))
+ (it "handles a fully constructed jack-in-cmd."
+ ;; TODO is it worth generating this?
+ (let ((cmd (concat "bash " script " /usr/local/bin/lein update-in :dependencies conj \[nrepl/nrepl\ \"1.0.0\"\] -- update-in :plugins conj \[cider/cider-nrepl\ \"0.43.0\"\] -- update-in :plugins conj \[mx.cider/lein-enrich-classpath\ \"1.18.2\"\] -- update-in :middleware conj cider.enrich-classpath.plugin-v2/middleware -- repl :headless :host localhost")))
+ (expect (cider--enriched-cmd-p cmd)
+ :to-equal script))))))))
+
 ;;; cider-jack-in tests
 (describe "cider--gradle-dependency-notation"
  (it "returns a GAV when given a two-element list"