Make x509-swoop more restrictive, avoiding duplicates.

Bogus PEM-regions could case x509-dwim to send whole buffer to view
functions. If the first thing in the file happened to be, for example, a
certificate, then that would be output to the result buffer. Causing copies of
the same cert several times.

x509-mode-tests.el

@@ -408,7 +408,7 @@ Repeat with `x509-dwim' which should produce the same result."
              test-files
            (list test-files))))
     (dolist (test-file files)
-      (dolist (view-func (list view-command 'x509-dwim))
+      (dolist (view-func (list view-command #'x509-dwim))
         (with-temp-buffer
           (insert-file-contents-literally (find-testfile test-file))
           (let ((view-buffer (funcall view-func)))
@@ -774,12 +774,20 @@ SEQUENCE             30 0C
       (let ((swoop-buffer (x509-swoop)))
         (should swoop-buffer)
         (with-current-buffer swoop-buffer
-          (check-content-helper swoop-buffer "Certificate:")
-          (check-content-helper swoop-buffer "Certificate Request:")
-          (check-content-helper swoop-buffer "DH Parameters:")
-          (check-content-helper swoop-buffer "Public-Key:")
-          (check-content-helper swoop-buffer "EC-Parameters: (512 bit)")
-          (check-content-helper swoop-buffer x509-swoop-separator)
+          (should (re-search-forward "Certificate:" nil t))
+          (should (re-search-forward x509-swoop-separator nil t))
+          ;; Should _not_ find another certificate. This used to be a bug where
+          ;; dwim would end up sending the whole buffer, producing the first
+          ;; certificate again.
+          (should-not (re-search-forward "Certificate:" nil t))
+          (should (re-search-forward "Certificate Request:" nil t))
+          (should (re-search-forward x509-swoop-separator nil t))
+          (should (re-search-forward "DH Parameters:"))
+          (should (re-search-forward x509-swoop-separator nil t))
+          (should (re-search-forward "Public-Key:"))
+          (should (re-search-forward x509-swoop-separator nil t))
+          (should (re-search-forward "EC-Parameters: (512 bit)"))
+          (should-not (re-search-forward x509-swoop-separator nil t))
           (x509-mode-kill-buffer)))
       (with-current-buffer src-buffer
         (should (= (point) 1322)))))

x509-mode.el

@@ -1009,8 +1009,9 @@ Intended to be called in a `x509-mode' or `x509-asn1-mode' buffer."
                  (or x509--x509-asn1-mode-shadow-arguments
                      x509-asn1parse-default-arg)
                  'x509--viewasn1-history 'x509-asn1-mode)
-              ;; Else determine type and do x509-mode
-              (x509-dwim))))))))
+              ;; Else determine type and do x509-mode. Only consider PEM
+              ;; regions.
+              (x509--do-dwim t))))))))
 
 ;; ---------------------------------------------------------------------------
 ;;;###autoload
@@ -1048,16 +1049,15 @@ if the buffer contains data of certain type."
                 (apply #'call-process-region proc-args)))
       (kill-buffer in-buf))))
 
-;; ---------------------------------------------------------------------------
-;;;###autoload
-(defun x509-dwim ()
+(defun x509--do-dwim (only-pem-region)
   "Guess the type of object and call the corresponding view-function.
 
 Look at -----BEGIN header for known object types.  Then test
-different openssl commands until one succeeds.  Call
-`x509-viewasn1' as a last resort.
-Return the output buffer."
-  (interactive)
+different openssl commands until one succeeds.
+If ONLY-PEM-REGION is nil, call `x509-viewasn1' as a last resort.
+If ONLY-PEM-REGION it t, only consider known PEM regions, i.e. don't send
+buffer content to `x509--dwim-tester'.
+Return the output buffer or nil"
   (pcase (x509--pem-region-type)
     ((or "CERTIFICATE" "TRUSTED CERTIFICATE")
      (call-interactively #'x509-viewcert))
@@ -1072,6 +1072,8 @@ Return the output buffer."
     ("X509 CRL" (call-interactively #'x509-viewcrl))
     (_
      (cond
+      (only-pem-region
+       nil)
       ((x509--dwim-tester x509-x509-default-arg)
        (call-interactively #'x509-viewcert))
       ((x509--dwim-tester x509-crl-default-arg)
@@ -1091,6 +1093,13 @@ Return the output buffer."
       (t
        (call-interactively #'x509-viewasn1))))))
 
+;; ---------------------------------------------------------------------------
+;;;###autoload
+(defun x509-dwim ()
+  "Guess the type of object and call the corresponding view-function."
+  (interactive)
+  (x509--do-dwim nil))
+
 ;; ---------------------------------------------------------------------------
 ;;;###autoload
 (defun x509-swoop ()
@@ -1110,7 +1119,8 @@ Return view buffer on success."
     (goto-char (point-min))
     (while (re-search-forward "-----BEGIN" nil t)
       (goto-char (match-beginning 0))
-      (when-let* ((tmp-output-buffer (x509-dwim)))
+      ;; Call x509--do-dwim. Only consider valid PEM-regions.
+      (when-let* ((tmp-output-buffer (x509--do-dwim t)))
         (with-current-buffer tmp-output-buffer
           ;; Only consider x509-mode output. We don't want asn1.
           (if (eq major-mode 'x509-mode)