branch: elpa/buttercup
commit 205e18e700301ea0b672c1564330c4658556d042
Author: Ryan C. Thompson <r...@thompsonclan.org>
Commit: Ryan C. Thompson <r...@thompsonclan.org>
Warn when :var is used with a special variable
Buttercup's ":var" and ":var*" forms only support lexical variables,
so using a special variable in these forms will almost certainly not
do what the test author expects.
See #127.
---
buttercup.el | 38 ++++++++++++++++++++++++++------------
1 file changed, 26 insertions(+), 12 deletions(-)
diff --git a/buttercup.el b/buttercup.el
index f7349f357f..e05dad32f0 100644
--- a/buttercup.el
+++ b/buttercup.el
@@ -951,19 +951,33 @@ mainly calls to `describe', `it' and `before-each'."
(unless lexical-binding
(signal 'buttercup-dynamic-binding-error
"buttercup requires `lexical-binding' to be t"))
- (let ((new-body
- (cond
- ((eq (elt body 0) :var)
- `((let ,(elt body 1)
- ,@(cddr body))))
- ((eq (elt body 0) :var*)
- `((let* ,(elt body 1)
- ,@(cddr body))))
- (t body))))
- (if (or (memq :var new-body)
- (memq :var* new-body))
+ ;; Convert `:var' or `:var*' to a lexical let form
+ (when
+ (memq (elt body 0) '(:var :var*))
+ (let ((let-form-to-use (if (eq (elt body 0) :var) 'let 'let*))
+ (let-bindings (elt body 1))
+ (let-body (cddr body)))
+ ;; Verify that all the specified variables are lexical
+ (cl-loop
+ for binding in let-bindings
+ for var = (if (symbolp binding) binding (car binding))
+ when (special-variable-p var)
+ do (display-warning
+ 'buttercup-describe
+ (concat "Possible erroneous use of special variable `"
+ (symbol-name var)
+ "' in :var(*) form")))
+ ;; Wrap new body in the appropriate let form
+ (setq body
+ `((,let-form-to-use
+ ;; Let bindings
+ ,let-bindings
+ ;; Let body
+ ,@let-body)))))
+ (if (or (memq :var body)
+ (memq :var* body))
`(error "buttercup: :var(*) found in invalid position of describe form
\"%s\"" ,description)
- `(buttercup-describe ,description (lambda () ,@new-body)))))
+ `(buttercup-describe ,description (lambda () ,@body))))
(defun buttercup-describe (description body-function)
"Function to handle a `describe' form.
