[elpa] externals/relint cbde6e35c7 4/6: Add check for duplicates in rx or-forms

[Mattias Engdegård]

branch: externals/relint
commit cbde6e35c777ce9e1fe5ace93d3d4374c867d2fd
Author: Mattias Engdegård <mattiase@acm.org>
Commit: Mattias Engdegård <mattiase@acm.org>

    Add check for duplicates in rx or-forms
    
    Since rx may run `regexp-opt` on strings in an or-pattern and that
    function implicitly deduplicates the set of strings, we would
    otherwise not know about the duplication.
---
 relint.el        | 17 +++++++++++++++++
 test/11.elisp    |  3 +++
 test/11.expected |  4 ++++
 3 files changed, 24 insertions(+)

diff --git a/relint.el b/relint.el
index 753a6e2c32..2b293cff99 100644
--- a/relint.el
+++ b/relint.el
@@ -1470,6 +1470,23 @@ than just to a surrounding or producing expression."
             'group 'submatch
             'group-n 'submatch-n)
        . ,args)
+     (when (memq (car item) '(| or))
+       ;; Check or-patterns for duplicates, because if rx runs `regexp-opt'
+       ;; on them then they are effectively deduplicated and we'd never
+       ;; know about it.
+       (let ((i 1)
+             (tail args))
+         (while (consp tail)
+           (when (member (car tail) (cdr tail))
+             (relint--warn pos (if exact-path (cons i path) path)
+                           (format-message
+                            "Duplicated rx form in or-pattern: %s"
+                             (replace-regexp-in-string
+                              (rx (+ (in " \n"))) " "
+                              (string-trim (xr-pp-rx-to-str (car tail)))
+                              t t))))
+           (setq i (1+ i))
+           (setq tail (cdr tail)))))
      ;; Form with subforms: recurse.
      (let ((i 1))
        (dolist (arg args)
diff --git a/test/11.elisp b/test/11.elisp
index d629a5639a..3f4527b23a 100644
--- a/test/11.elisp
+++ b/test/11.elisp
@@ -31,4 +31,7 @@
   (rx (any "a-z" ?m))
   (rx (any "a-f" "\000-\377"))
   (rx (any "\240-\277" "\000-\377"))
+
+  (rx (or "abc" ?A "def" "ghi" ?A "def"))
+  (rx (| "abc" (= 3 ?*) "def" (= 3 ?*) "ghi" "abc"))
   )
diff --git a/test/11.expected b/test/11.expected
index 2c0eb6b5b1..9b8c9b1b19 100644
--- a/test/11.expected
+++ b/test/11.expected
@@ -59,3 +59,7 @@
 11.elisp:33:25: Range `\000-\377' overlaps previous `\240-\277' (pos 0)
   "\000-\377"
    ^
+11.elisp:35:17: Duplicated rx form in or-pattern: ?A
+11.elisp:35:20: Duplicated rx form in or-pattern: "def"
+11.elisp:36:10: Duplicated rx form in or-pattern: "abc"
+11.elisp:36:16: Duplicated rx form in or-pattern: (= 3 ?*)