Subject: 30.0.50; Mistyped shy group regexps

From: Basil Contovounesios <[email-masked]>
Date: Wed, 14 Jun 2023 17:43:39 +0100

Severity: minor
Tags: patch

Further to https://bugs.gnu.org/64019#14, I attach a patch which tweaks
four redundant or seemingly mistyped instances of \(:?...\), i.e. a
numbered group starting with an optional colon in place of the likelier
shy group.

CCing:
- Alan to review the change to c-or-c++-mode--regexp
  (along with its clone c-ts-mode--c-or-c++-regexp)
- Dmitry to review the change in vc-git
- Paul for any comments on the time handling in vc-git-annotate-time

In vc-git-annotate-time, the mistyped group added in [1] throws off the
match string indices that are later passed to encode-time: by my reading
the hour argument by chance continues to be specified correctly, but the
minutes argument receives the number of hours, the seconds argument the
number of minutes, and the timezone argument the number of seconds.

[1]: Display shorter dates in Git annotate output
576fba5f58d 2015-05-17 02:47:17 +0300
https://git.sv.gnu.org/cgit/emacs.git/commit/?id=576fba5f58d

Even after correcting the shy group, the timezone parsing doesn't seem
right to me: encode-time expects a UTC offset in seconds, but is passed
e.g. (string-to-number "+0100")=100s instead of the expected 1hr=3600s.

IMO there is another minor issue with the regexp towards its end:

  \([-+0-9]+\) *[0-9]+

The trailing line number should be separated from the preceding
timestamp by at least one space.  So, the optional space would ideally
precede rather than follow the optional time+zone components.

The patch fixes this and the match/timezone handling by splitting the
datetime string into only three components (date, time, zone) and
delegating to iso8601-parse.

>From 9ead0ba1dd2676105269ff1472a206a250539b18 Mon Sep 17 00:00:00 2001
From: "Basil L. Contovounesios" <[email-masked]>
Date: Mon, 12 Jun 2023 00:23:56 +0100
Subject: [PATCH] Fix some shy group regexps

These issues were caught by modified versions of the GNU ELPA
packages xr and relint:
- https://github.com/mattiase/xr/pull/6
- https://github.com/mattiase/relint/pull/14

* lisp/gnus-art.el (gnus-parse-news-url): Remove redundant numbered
group and calls to match-string.

* lisp/progmodes/c-ts-mode.el (c-ts-mode--c-or-c++-regexp):
* lisp/progmodes/cc-mode.el (c-or-c++-mode--regexp): Fix shy group
mistyped as optional colon (bug#64019#29).

* lisp/vc/vc-git.el (vc-git-annotate-time): Ditto.  Also fix
timezone parsing by using iso8601-parse.
* test/lisp/vc/vc-git-tests.el (vc-git-test-annotate-time): New
test.
---
 lisp/gnus/gnus-art.el        |  7 +++----
 lisp/progmodes/c-ts-mode.el  |  2 +-
 lisp/progmodes/cc-mode.el    |  2 +-
 lisp/vc/vc-git.el            | 19 ++++++++++++-------
 test/lisp/vc/vc-git-tests.el | 17 +++++++++++++++++
 5 files changed, 34 insertions(+), 13 deletions(-)

diff --git a/lisp/gnus/gnus-art.el b/lisp/gnus/gnus-art.el
index 6a7a3f41746..6f201f9c3df 100644
--- a/lisp/gnus/gnus-art.el
+++ b/lisp/gnus/gnus-art.el
@@ -8331,11 +8331,10 @@ gnus-parse-news-url
       (when (looking-at "\\([A-Za-z]+\\):")
 	(setq scheme (match-string 1))
 	(goto-char (match-end 0)))
-      (when (looking-at "//\\([^:/]+\\)\\(:?\\)\\([0-9]+\\)?/")
+      (when (looking-at "//\\([^:/]+\\):?\\([0-9]+\\)?/")
 	(setq server (match-string 1))
-	(setq port (if (stringp (match-string 3))
-		       (string-to-number (match-string 3))
-		     (match-string 3)))
+        (setq port (and (match-beginning 2)
+                        (string-to-number (match-string 2))))
 	(goto-char (match-end 0)))
 
       (cond
diff --git a/lisp/progmodes/c-ts-mode.el b/lisp/progmodes/c-ts-mode.el
index 4b83c6733a2..9e911192be3 100644
--- a/lisp/progmodes/c-ts-mode.el
+++ b/lisp/progmodes/c-ts-mode.el
@@ -1355,7 +1355,7 @@ c-ts-mode--c-or-c++-regexp
               "\\|" id "::"
               "\\|" id ws-maybe "=\\)"
               "\\|" "\\(?:inline" ws "\\)?namespace"
-              "\\(:?" ws "\\(?:" id "::\\)*" id "\\)?" ws-maybe "{"
+              "\\(?:" ws "\\(?:" id "::\\)*" id "\\)?" ws-maybe "{"
               "\\|" "class"     ws id
               "\\(?:" ws "final" "\\)?" ws-maybe "[:{;\n]"
               "\\|" "struct"     ws id "\\(?:" ws "final" ws-maybe "[:{\n]"
diff --git a/lisp/progmodes/cc-mode.el b/lisp/progmodes/cc-mode.el
index 11a1d3fe6c2..5cf9b7e17f8 100644
--- a/lisp/progmodes/cc-mode.el
+++ b/lisp/progmodes/cc-mode.el
@@ -2859,7 +2859,7 @@ c-or-c++-mode--regexp
                                      "\\|" id "::"
                                      "\\|" id ws-maybe "=\\)"
               "\\|" "\\(?:inline" ws "\\)?namespace"
-                    "\\(:?" ws "\\(?:" id "::\\)*" id "\\)?" ws-maybe "{"
+                    "\\(?:" ws "\\(?:" id "::\\)*" id "\\)?" ws-maybe "{"
               "\\|" "class"     ws id
                     "\\(?:" ws "final" "\\)?" ws-maybe "[:{;\n]"
               "\\|" "struct"     ws id "\\(?:" ws "final" ws-maybe "[:{\n]"
diff --git a/lisp/vc/vc-git.el b/lisp/vc/vc-git.el
index a3469b71386..dfca944dc74 100644
--- a/lisp/vc/vc-git.el
+++ b/lisp/vc/vc-git.el
@@ -1723,14 +1723,19 @@ vc-git-annotate-command
 
 (declare-function vc-annotate-convert-time "vc-annotate" (&optional time))
 
+(autoload 'decoded-time-set-defaults "time-date")
+(autoload 'iso8601-parse "iso8601")
+
 (defun vc-git-annotate-time ()
-  (and (re-search-forward "^[0-9a-f^]+[^()]+(.*?\\([0-9]+\\)-\\([0-9]+\\)-\\([0-9]+\\) \\(:?\\([0-9]+\\):\\([0-9]+\\):\\([0-9]+\\) \\([-+0-9]+\\)\\)? *[0-9]+) " nil t)
-       (vc-annotate-convert-time
-        (apply #'encode-time (mapcar (lambda (match)
-                                       (if (match-beginning match)
-                                           (string-to-number (match-string match))
-                                         0))
-                                     '(6 5 4 3 2 1 7))))))
+  (and (re-search-forward "^[0-9a-f^]+[^()]+(.*?\\([0-9]+-[0-9]+-[0-9]+\\)\\(?: \\([0-9]+:[0-9]+:[0-9]+\\) \\([-+0-9]+\\)\\)? +[0-9]+) " nil t)
+       (let* ((dt (match-string 1))
+              (dt (if (not (match-beginning 2)) dt
+                    ;; Format as ISO 8601.
+                    (concat dt "T" (match-string 2) (match-string 3))))
+              (decoded (ignore-errors (iso8601-parse dt))))
+         (and decoded
+              (vc-annotate-convert-time
+               (encode-time (decoded-time-set-defaults decoded)))))))
 
 (defun vc-git-annotate-extract-revision-at-line ()
   (save-excursion
diff --git a/test/lisp/vc/vc-git-tests.el b/test/lisp/vc/vc-git-tests.el
index f12c5d3434b..b331b77cf01 100644
--- a/test/lisp/vc/vc-git-tests.el
+++ b/test/lisp/vc/vc-git-tests.el
@@ -64,4 +64,21 @@ vc-git-test--run-program-version-test
              (actual-output (vc-git--program-version)))
     (should (equal actual-output expected-output))))
 
+(ert-deftest vc-git-test-annotate-time ()
+  "Test `vc-git-annotate-time'."
+  (require 'vc-annotate)
+  (with-temp-buffer
+    (insert "\
+00000000 (Foo Bar 2023-06-14  1) a
+00000001 (Foo Bar 2023-06-14 00:00:00 -0130  2) b
+00000002 (Foo Bar 2023-06-14 00:00:00 +0145  3) c
+00000003 (Foo Bar 2023-06-14 00:00:00  4) d
+00000004 (Foo Bar 0-0-0  5) \n")
+    (goto-char (point-min))
+    (should (floatp (vc-git-annotate-time)))
+    (should (> (vc-git-annotate-time)
+               (vc-git-annotate-time)))
+    (should-not (vc-git-annotate-time))
+    (should-not (vc-git-annotate-time))))
+
 ;;; vc-git-tests.el ends here
-- 
2.34.1

WDYT?

Thanks,

-- 
Basil

In GNU Emacs 30.0.50 (build 1, x86_64-pc-linux-gnu, X toolkit, cairo
 version 1.16.0, Xaw3d scroll bars) of 2023-06-13 built on blc
Repository revision: 81932ebcfa56a33fcb1c7d9f91094e2b1f6e9b77
Repository branch: blc/treesit/master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101004
System Description: Ubuntu 22.04.2 LTS

Configured using:
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Configured features:
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