bug#50008: 28.0.50; ERC sends empty lines with user input

bug#50008: 28.0.50; ERC sends empty lines with user input

[J.P.]

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Tags: patch

Hi, this one may take some seeing to believe. For proof, set up a local
server or proxy (I can help with this) or fire up and tweak the
behavioral tests included with these bugs [1] or ask a network oper
friend to check their logs (they'll already know immediately if you
mention ERC).

BTW, the included unit tests may require a quick refresher on the
relevant portions of the codebase. Happy to make a mess of explaining
the specifics. Thanks.


[1] https://debbugs.gnu.org/cgi/bugreport.cgi?bug=48598
    https://debbugs.gnu.org/cgi/bugreport.cgi?bug=49860


In GNU Emacs 28.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.30, cairo version 1.17.4)
 of 2021-08-09 built on localhost
Repository revision: aeec97fae0ccfcc4dc406a5e0e4c0a94b834cac4
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12011000
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From 78314388e91aa263dfbaaf24528eac8ddd15e353 Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <jp@neverwas.me>
Date: Sun, 13 Jun 2021 02:15:55 -0700
Subject: [PATCH] Don't send empty lines for implicit targets in ERC

* erc.el (erc-send-input-line): Previously, any line typed into a
query or channel buffer without an explicit user-command
handler (meaning most lines), would be sent twice because a trailing
newline (linefeed) would be appended. This has been verified by
checking IRCd server logs. IRCds won't return an error upon receiving
an empty message, but they also won't forward them to channel
subscribers and DM pals.

* erc-tests.el: Add test for erc-process-input-line, which also
indirectly tests erc-send-input-line. It also tests the command
lookup and dispatch facility
---
 lisp/erc/erc.el            | 21 ++++++-------
 test/lisp/erc/erc-tests.el | 61 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 70 insertions(+), 12 deletions(-)

diff --git a/lisp/erc/erc.el b/lisp/erc/erc.el
index 73202016ba..733b0a4510 100644
--- a/lisp/erc/erc.el
+++ b/lisp/erc/erc.el
@@ -2791,20 +2791,17 @@ erc-message-type-member
   (let ((prop-val (erc-get-parsed-vector position)))
     (and prop-val (member (erc-response.command prop-val) list))))
 
-(defvar-local erc-send-input-line-function 'erc-send-input-line)
+(defvar-local erc-send-input-line-function 'erc-send-input-line
+  "Function for sending lines lacking a leading user command.
+When a line typed into a buffer contains an explicit command, like /msg,
+a corresponding handler (here, erc-cmd-MSG) is called.  But lines typed
+into a channel or query buffer already have an implicit target and
+command (PRIVMSG).  This function is called on such occasions and also
+for special purposes (see erc-dcc.el).")
 
 (defun erc-send-input-line (target line &optional force)
-  "Send LINE to TARGET.
-
-See also `erc-server-send'."
-  (setq line (format "PRIVMSG %s :%s"
-                     target
-                     ;; If the line is empty, we still want to
-                     ;; send it - i.e. an empty pasted line.
-                     (if (string= line "\n")
-                         " \n"
-                       line)))
-  (erc-server-send line force target))
+  "Send LINE to TARGET."
+  (erc-message "PRIVMSG" (concat target " " line) force))
 
 (defun erc-get-arglist (fun)
   "Return the argument list of a function without the parens."
diff --git a/test/lisp/erc/erc-tests.el b/test/lisp/erc/erc-tests.el
index d13397274a..e448a06db0 100644
--- a/test/lisp/erc/erc-tests.el
+++ b/test/lisp/erc/erc-tests.el
@@ -109,3 +109,64 @@ erc-ring-previous-command
         (should (looking-at "abc")))))
   (when noninteractive
     (kill-buffer "*#fake*")))
+
+;; The point of this test is to ensure output is handled identically
+;; regardless of whether a command handler is summoned.
+
+(ert-deftest erc-process-input-line ()
+  (let (erc-server-last-sent-time
+        erc-server-flood-queue
+        (orig-erc-cmd-MSG (symbol-function 'erc-cmd-MSG))
+        calls)
+    (with-temp-buffer
+      (cl-letf (((symbol-function 'erc-cmd-MSG)
+                 (lambda (line)
+                   (push line calls)
+                   (funcall orig-erc-cmd-MSG line)))
+                ((symbol-function 'erc-server-buffer)
+                 (lambda () (current-buffer)))
+                ((symbol-function 'erc-server-process-alive)
+                 (lambda () t))
+                ((symbol-function 'erc-server-send-queue)
+                 #'ignore)
+                ((symbol-function 'erc-default-target)
+                 (lambda () "" "#chan")))
+
+        (ert-info ("Dispatch to user command handler")
+
+          (ert-info ("Baseline")
+            (erc-process-input-line "/msg #chan hi\n")
+            (should (equal (pop calls) " #chan hi"))
+            (should (equal (pop erc-server-flood-queue)
+                           '("PRIVMSG #chan :hi\r\n" . utf-8))))
+
+          (ert-info ("Spaces preserved")
+            (erc-process-input-line "/msg #chan hi you\n")
+            (should (equal (pop calls) " #chan hi you"))
+            (should (equal (pop erc-server-flood-queue)
+                           '("PRIVMSG #chan :hi you\r\n" . utf-8))))
+
+          (ert-info ("Empty line honored")
+            (erc-process-input-line "/msg #chan\n")
+            (should (equal (pop calls) " #chan"))
+            (should (equal (pop erc-server-flood-queue)
+                           '("PRIVMSG #chan :\r\n" . utf-8)))))
+
+        (ert-info ("Implicit cmd via `erc-send-input-line-function'")
+
+          (ert-info ("Baseline")
+            (erc-process-input-line "hi")
+            (should (equal (pop erc-server-flood-queue)
+                           '("PRIVMSG #chan :hi\r\n" . utf-8))))
+
+          (ert-info ("Spaces preserved")
+            (erc-process-input-line "hi you")
+            (should (equal (pop erc-server-flood-queue)
+                           '("PRIVMSG #chan :hi you\r\n" . utf-8))))
+
+          (ert-info ("Empty line transmitted without injected-space kludge")
+            (erc-process-input-line "")
+            (should (equal (pop erc-server-flood-queue)
+                           '("PRIVMSG #chan :\r\n" . utf-8))))
+
+          (should-not calls))))))
-- 
2.31.1

bug#50008: 28.0.50; ERC sends empty lines with user input

[Stefan Kangas]

"J.P." <jp@neverwas.me> writes:

> Tags: patch
>
> Hi, this one may take some seeing to believe. For proof, set up a local
> server or proxy (I can help with this) or fire up and tweak the
> behavioral tests included with these bugs [1] or ask a network oper
> friend to check their logs (they'll already know immediately if you
> mention ERC).
>
> BTW, the included unit tests may require a quick refresher on the
> relevant portions of the codebase. Happy to make a mess of explaining
> the specifics. Thanks.
>
>
> [1] https://debbugs.gnu.org/cgi/bugreport.cgi?bug=48598
>     https://debbugs.gnu.org/cgi/bugreport.cgi?bug=49860

Copying in the ERC maintainer Amin Bandali here.

Amin, could you help review this patch?

bug#50008: 28.0.50; ERC sends empty lines with user input

[Lars Ingebrigtsen]

"J.P." <jp@neverwas.me> writes:

> Subject: [PATCH] Don't send empty lines for implicit targets in ERC

Makes sense to me, and testing it a bit doesn't seem to show any
regressions, so I've now pushed this to Emacs 29.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#50008: [J.P.] Re: bug#50008: 28.0.50; ERC sends empty lines with user input

[J.P.]

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Prior attempt was blocked (archived).

-------------------- Start of forwarded message --------------------
From: "J.P." <jp@neverwas.me>
To: Lars Ingebrigtsen <larsi@gnus.org>
Cc: 50008@debbugs.gnu.org,  bandali@gnu.org, emacs-erc@gnu.org
Subject: Re: bug#50008: 28.0.50; ERC sends empty lines with user input
Date: Tue, 22 Mar 2022 01:37:20 -0700


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Lars Ingebrigtsen <larsi@gnus.org> writes:

> "J.P." <jp@neverwas.me> writes:
>
>> Subject: [PATCH] Don't send empty lines for implicit targets in ERC
>
> Makes sense to me, and testing it a bit doesn't seem to show any
> regressions, so I've now pushed this to Emacs 29.

I just noticed a regression that remained hidden all this while
because I failed to call the function realistically in its unit test.
Luckily, this only affects master.

I've attached a fix here just to have something for the record. But I
figure there's little harm in deferring and tossing it in with some
other stuff I'm preparing (in a new bug report) to try and simplify the
input processing situation. Thanks.


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> From dc7005fe509f573e86aef0a87ec8b650a1aacec4 Mon Sep 17 00:00:00 2001
From: "F. Jason Park" <jp@neverwas.me>
Date: Mon, 21 Mar 2022 19:21:57 -0700
Subject: [PATCH] Fix regression in erc-send-input-line

* lisp/erc/erc.el (erc-send-input-line): Restore remedial single-space
padding to ensure empty messages typed at the prompt without an
explicit /msg aren't rejected by the server.  This behavior is only
noticeable when `erc-send-whitespace-lines' is active.

* test/lisp/erc/erc-tests.el (erc-process-input-line): Add trailing
newline to more correctly simulate how it's actually called by
`erc-send-input'. (Bug#50008)
---
 lisp/erc/erc.el            |  2 ++
 test/lisp/erc/erc-tests.el | 10 +++++-----
 2 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/lisp/erc/erc.el b/lisp/erc/erc.el
index 52fe106f2d..d8ef62cf93 100644
--- a/lisp/erc/erc.el
+++ b/lisp/erc/erc.el
@@ -2817,6 +2817,8 @@ erc-send-input-line-function
 
 (defun erc-send-input-line (target line &optional force)
   "Send LINE to TARGET."
+  (when (string= line "\n")
+    (setq line " \n"))
   (erc-message "PRIVMSG" (concat target " " line) force))
 
 (defun erc-get-arglist (fun)
diff --git a/test/lisp/erc/erc-tests.el b/test/lisp/erc/erc-tests.el
index 520f10dd4e..10e3c16dfc 100644
--- a/test/lisp/erc/erc-tests.el
+++ b/test/lisp/erc/erc-tests.el
@@ -340,19 +340,19 @@ erc-process-input-line
         (ert-info ("Implicit cmd via `erc-send-input-line-function'")
 
           (ert-info ("Baseline")
-            (erc-process-input-line "hi")
+            (erc-process-input-line "hi\n")
             (should (equal (pop erc-server-flood-queue)
                            '("PRIVMSG #chan :hi\r\n" . utf-8))))
 
           (ert-info ("Spaces preserved")
-            (erc-process-input-line "hi you")
+            (erc-process-input-line "hi you\n")
             (should (equal (pop erc-server-flood-queue)
                            '("PRIVMSG #chan :hi you\r\n" . utf-8))))
 
-          (ert-info ("Empty line transmitted without injected-space kludge")
-            (erc-process-input-line "")
+          (ert-info ("Empty line transmitted with injected-space kludge")
+            (erc-process-input-line "\n")
             (should (equal (pop erc-server-flood-queue)
-                           '("PRIVMSG #chan :\r\n" . utf-8))))
+                           '("PRIVMSG #chan : \r\n" . utf-8))))
 
           (should-not calls))))))
 
-- 
2.35.1


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