--- Begin Message ---
Package: emacs24
Version: 24.5+1-5+b1
Severity: normal
Tags: upstream patch
Dear Maintainer,
There is a bug in the version of TRAMP included with Emacs 24.5 that
causes Emacs to hang for at least 30 seconds -- on my system, about two
minutes -- when Emacs loads TRAMP.
The hang occurs when Emacs spawns ssh processes when initialising the
variable `tramp-ssh-controlmaster-options'. If your ISP's DNS server
likes to hijack failed lookups to redirect the user to a branded search
engine, these ssh processes hang for a long time before timing out [1].
This bug affects all Emacs Lisp addons that load TRAMP as part of their
startup, of which Helm [2] and Magit [3] are prominent.
There are two workarounds for users: switch to DNS servers which don't
do this kind of hijacking (e.g. Google's public resolvers), or set
`tramp-ssh-controlmaster-options' to nil in your init file, before code
which causes TRAMP to be loaded is executed.
This bug is fixed Emacs 25, but according to the emacs-devel mailing
list there is not likely to be another point release of Emacs 24
containing the fix [4]. I'm not sure whether this bug counts as
release-critical by Debian standards, but it would be a shame for it to
get frozen in Stretch. I attach a debdiff backporting the fix as a
quilt patch.
Sean Whitton
[1] https://debbugs.gnu.org/cgi/bugreport.cgi?bug=20015
[2] https://github.com/emacs-helm/helm/issues/1000
[3] http://magit.vc/manual/magit/Emacs-245-hangs-when-loading-Magit.html
[4] https://lists.gnu.org/archive/html/emacs-devel/2015-07/msg00329.html
diff -Nru emacs24-24.5+1/debian/changelog emacs24-24.5+1/debian/changelog
--- emacs24-24.5+1/debian/changelog 2015-11-27 13:34:01.000000000 -0700
+++ emacs24-24.5+1/debian/changelog 2016-01-10 12:20:03.000000000 -0700
@@ -1,3 +1,11 @@
+emacs24 (24.5+1-5.1) unstable; urgency=medium
+
+ * Non-maintainer upload.
+ * Backport fix for upstream bug
+ <https://debbugs.gnu.org/cgi/bugreport.cgi?bug=20015>.
+
+ -- Sean Whitton <[email protected]> Sun, 10 Jan 2016 12:19:19 -0700
+
emacs24 (24.5+1-5) unstable; urgency=medium
* Only test timestamp preservation for $(flavor)-el. Only check
diff -Nru emacs24-24.5+1/debian/patches/0010-Emacs-should-no-longer-hang-when-loading-TRAMP.patch emacs24-24.5+1/debian/patches/0010-Emacs-should-no-longer-hang-when-loading-TRAMP.patch
--- emacs24-24.5+1/debian/patches/0010-Emacs-should-no-longer-hang-when-loading-TRAMP.patch 1969-12-31 17:00:00.000000000 -0700
+++ emacs24-24.5+1/debian/patches/0010-Emacs-should-no-longer-hang-when-loading-TRAMP.patch 2016-01-10 12:17:28.000000000 -0700
@@ -0,0 +1,341 @@
+From: Sean Whitton <[email protected]>
+Date: Sun, 10 Jan 2016 12:16:33 -0700
+Subject: Emacs should no longer hang when loading TRAMP
+
+Patch adapted from upstream repository commits 28caedba and 508049aa by
+Michael Albinus.
+---
+ lisp/net/tramp-adb.el | 2 ++
+ lisp/net/tramp-gvfs.el | 2 ++
+ lisp/net/tramp-sh.el | 81 +++++++++++++++++++++++++++++++++++++++++++++-----
+ lisp/net/tramp-smb.el | 6 ++++
+ lisp/net/tramp.el | 51 ++++---------------------------
+ 5 files changed, 89 insertions(+), 53 deletions(-)
+
+diff --git a/lisp/net/tramp-adb.el b/lisp/net/tramp-adb.el
+index f5e2019..cf1e05e 100644
+--- a/lisp/net/tramp-adb.el
++++ b/lisp/net/tramp-adb.el
+@@ -38,6 +38,7 @@
+ ;; Pacify byte-compiler.
+ (defvar directory-sep-char)
+
++;;;###tramp-autoload
+ (defcustom tramp-adb-program "adb"
+ "Name of the Android Debug Bridge program."
+ :group 'tramp
+@@ -48,6 +49,7 @@
+ (defconst tramp-adb-method "adb"
+ "*When this method name is used, forward all calls to Android Debug Bridge.")
+
++;;;###tramp-autoload
+ (defcustom tramp-adb-prompt
+ "^\\(?:[[:digit:]]*|?\\)?\\(?:[[:alnum:]]*@[[:alnum:]]*[^#\\$]*\\)?[#\\$][[:space:]]"
+ "Regexp used as prompt in almquist shell."
+diff --git a/lisp/net/tramp-gvfs.el b/lisp/net/tramp-gvfs.el
+index 1ea52eb..5988a28 100644
+--- a/lisp/net/tramp-gvfs.el
++++ b/lisp/net/tramp-gvfs.el
+@@ -127,6 +127,7 @@
+ ;;;###tramp-autoload
+ (add-to-list 'tramp-default-user-alist '("\\`synce\\'" nil nil))
+
++;;;###tramp-autoload
+ (defcustom tramp-gvfs-zeroconf-domain "local"
+ "Zeroconf domain to be used for discovering services, like host names."
+ :group 'tramp
+@@ -374,6 +375,7 @@ It has been changed in GVFS 1.14.")
+ ;; </signal>
+ ;; </interface>
+
++;;;###tramp-autoload
+ (defcustom tramp-bluez-discover-devices-timeout 60
+ "Defines seconds since last bluetooth device discovery before rescanning.
+ A value of 0 would require an immediate discovery during hostname
+diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
+index bd7aec9..0e30bfe 100644
+--- a/lisp/net/tramp-sh.el
++++ b/lisp/net/tramp-sh.el
+@@ -40,6 +40,7 @@
+ (defvar vc-git-program)
+ (defvar vc-hg-program)
+
++;;;###tramp-autoload
+ (defcustom tramp-inline-compress-start-size 4096
+ "The minimum size of compressing where inline transfer.
+ When inline transfer, compress transferred data of file
+@@ -48,6 +49,7 @@ If it is nil, no compression at all will be applied."
+ :group 'tramp
+ :type '(choice (const nil) integer))
+
++;;;###tramp-autoload
+ (defcustom tramp-copy-size-limit 10240
+ "The maximum file size where inline copying is preferred over an \
+ out-of-the-band copy.
+@@ -87,6 +89,27 @@ detected as prompt when being sent on echoing hosts, therefore.")
+ (defconst tramp-end-of-heredoc (md5 tramp-end-of-output)
+ "String used to recognize end of heredoc strings.")
+
++;;;###tramp-autoload
++(defcustom tramp-use-ssh-controlmaster-options t
++ "Whether to use `tramp-ssh-controlmaster-options'."
++ :group 'tramp
++ :version "24.4"
++ :type 'boolean)
++
++(defvar tramp-ssh-controlmaster-options nil
++ "Which ssh Control* arguments to use.
++
++If it is a string, it should have the form
++\"-o ControlMaster=auto -o ControlPath='tramp.%%r@%%h:%%p'
++-o ControlPersist=no\". Percent characters in the ControlPath
++spec must be doubled, because the string is used as format string.
++
++Otherwise, it will be auto-detected by Tramp, if
++`tramp-use-ssh-controlmaster-options' is non-nil. The value
++depends on the installed local ssh version.
++
++The string is used in `tramp-methods'.")
++
+ ;; Initialize `tramp-methods' with the supported methods.
+ ;;;###tramp-autoload
+ (add-to-list 'tramp-methods
+@@ -471,6 +494,7 @@ not be set here. Instead, it should be set via `tramp-remote-path'."
+ :version "24.4"
+ :type '(repeat string))
+
++;;;###tramp-autoload
+ (defcustom tramp-sh-extra-args '(("/bash\\'" . "-norc -noprofile"))
+ "Alist specifying extra arguments to pass to the remote shell.
+ Entries are (REGEXP . ARGS) where REGEXP is a regular expression
+@@ -2331,10 +2355,7 @@ The method used must be an out-of-band method."
+ spec (format-spec-make
+ ?t (tramp-get-connection-property
+ (tramp-get-connection-process v) "temp-file" ""))
+- options (format-spec
+- (if tramp-use-ssh-controlmaster-options
+- tramp-ssh-controlmaster-options "")
+- spec)
++ options (format-spec (tramp-ssh-controlmaster-options v) spec)
+ spec (format-spec-make
+ ?h host ?u user ?p port ?r listener ?c options
+ ?k (if keep-date " " ""))
+@@ -4496,7 +4517,7 @@ Gateway hops are already opened."
+
+ ;; In case the host name is not used for the remote shell
+ ;; command, the user could be misguided by applying a random
+- ;; hostname.
++ ;; host name.
+ (let* ((v (car target-alist))
+ (method (tramp-file-name-method v))
+ (host (tramp-file-name-host v)))
+@@ -4518,6 +4539,53 @@ Gateway hops are already opened."
+ ;; Result.
+ target-alist))
+
++(defun tramp-ssh-controlmaster-options (vec)
++ "Return the Control* arguments of the local ssh."
++ (cond
++ ;; No options to be computed.
++ ((or (null tramp-use-ssh-controlmaster-options)
++ (null (assoc "%c" (tramp-get-method-parameter
++ (tramp-file-name-method vec) 'tramp-login-args))))
++ "")
++
++ ;; There is already a value to be used.
++ ((stringp tramp-ssh-controlmaster-options) tramp-ssh-controlmaster-options)
++
++ ;; Determine the options.
++ (t (setq tramp-ssh-controlmaster-options "")
++ (let ((case-fold-search t))
++ (ignore-errors
++ (when (executable-find "ssh")
++ (with-temp-buffer
++ (tramp-call-process vec "ssh" nil t nil "-o" "ControlMaster")
++ (goto-char (point-min))
++ (when (search-forward-regexp "missing.+argument" nil t)
++ (setq tramp-ssh-controlmaster-options "-o ControlMaster=auto")))
++ (unless (zerop (length tramp-ssh-controlmaster-options))
++ (with-temp-buffer
++ ;; When we use a non-existing host name, we could run
++ ;; into DNS timeouts. So we use "localhost" with an
++ ;; improper port, expecting nobody runs sshd on the
++ ;; telnet port.
++ (tramp-call-process
++ vec "ssh" nil t nil
++ "-p" "23" "-o" "ControlPath=%C" "localhost")
++ (goto-char (point-min))
++ (setq tramp-ssh-controlmaster-options
++ (if (search-forward-regexp "unknown.+key" nil t)
++ (concat tramp-ssh-controlmaster-options
++ " -o ControlPath='tramp.%%r@%%h:%%p'")
++ (concat tramp-ssh-controlmaster-options
++ " -o ControlPath='tramp.%%C'"))))
++ (with-temp-buffer
++ (tramp-call-process vec "ssh" nil t nil "-o" "ControlPersist")
++ (goto-char (point-min))
++ (when (search-forward-regexp "missing.+argument" nil t)
++ (setq tramp-ssh-controlmaster-options
++ (concat tramp-ssh-controlmaster-options
++ " -o ControlPersist=no"))))))))
++ tramp-ssh-controlmaster-options)))
++
+ (defun tramp-maybe-open-connection (vec)
+ "Maybe open a connection VEC.
+ Does not do anything if a connection is already open, but re-opens the
+@@ -4593,8 +4661,7 @@ connection if a previous connection has died for some reason."
+ (let* ((target-alist (tramp-compute-multi-hops vec))
+ ;; We will apply `tramp-ssh-controlmaster-options'
+ ;; only for the first hop.
+- (options (if tramp-use-ssh-controlmaster-options
+- tramp-ssh-controlmaster-options ""))
++ (options (tramp-ssh-controlmaster-options vec))
+ (process-connection-type tramp-process-connection-type)
+ (process-adaptive-read-buffering nil)
+ (coding-system-for-read nil)
+diff --git a/lisp/net/tramp-smb.el b/lisp/net/tramp-smb.el
+index d5fe17f..14360b9 100644
+--- a/lisp/net/tramp-smb.el
++++ b/lisp/net/tramp-smb.el
+@@ -70,17 +70,20 @@
+ tramp-smb-method
+ '((tramp-parse-netrc "~/.netrc"))))
+
++;;;###tramp-autoload
+ (defcustom tramp-smb-program "smbclient"
+ "Name of SMB client to run."
+ :group 'tramp
+ :type 'string)
+
++;;;###tramp-autoload
+ (defcustom tramp-smb-acl-program "smbcacls"
+ "Name of SMB acls to run."
+ :group 'tramp
+ :type 'string
+ :version "24.4")
+
++;;;###tramp-autoload
+ (defcustom tramp-smb-conf "/dev/null"
+ "Path of the smb.conf file.
+ If it is nil, no smb.conf will be added to the `tramp-smb-program'
+@@ -280,6 +283,7 @@ See `tramp-actions-before-shell' for more info.")
+ Operations not mentioned here will be handled by the default Emacs primitives.")
+
+ ;; Options for remote processes via winexe.
++;;;###tramp-autoload
+ (defcustom tramp-smb-winexe-program "winexe"
+ "Name of winexe client to run.
+ If it isn't found in the local $PATH, the absolute path of winexe
+@@ -288,6 +292,7 @@ shall be given. This is needed for remote processes."
+ :type 'string
+ :version "24.3")
+
++;;;###tramp-autoload
+ (defcustom tramp-smb-winexe-shell-command "powershell.exe"
+ "Shell to be used for processes on remote machines.
+ This must be Powershell V2 compatible."
+@@ -295,6 +300,7 @@ This must be Powershell V2 compatible."
+ :type 'string
+ :version "24.3")
+
++;;;###tramp-autoload
+ (defcustom tramp-smb-winexe-shell-command-switch "-file -"
+ "Command switch used together with `tramp-smb-winexe-shell-command'.
+ This can be used to disable echo etc."
+diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
+index 79242a4..10bb769 100644
+--- a/lisp/net/tramp.el
++++ b/lisp/net/tramp.el
+@@ -73,6 +73,7 @@
+ "Edit remote files with a combination of ssh, scp, etc."
+ :group 'files
+ :group 'comm
++ :link '(custom-manual "(tramp)Top")
+ :version "22.1")
+
+ ;; Maybe we need once a real Tramp mode, with key bindings etc.
+@@ -306,46 +307,6 @@ started on the local host. You should specify a remote host
+ `localhost' or the name of the local host. Another host name is
+ useful only in combination with `tramp-default-proxies-alist'.")
+
+-;;;###tramp-autoload
+-(defcustom tramp-ssh-controlmaster-options
+- (let ((result "")
+- (case-fold-search t))
+- (ignore-errors
+- (when (executable-find "ssh")
+- (with-temp-buffer
+- (call-process "ssh" nil t nil "-o" "ControlMaster")
+- (goto-char (point-min))
+- (when (search-forward-regexp "missing.+argument" nil t)
+- (setq result "-o ControlMaster=auto")))
+- (unless (zerop (length result))
+- (with-temp-buffer
+- (call-process
+- "ssh" nil t nil "-o" "ControlPath=%C" "host.does.not.exist")
+- (goto-char (point-min))
+- (if (search-forward-regexp "unknown.+key" nil t)
+- (setq result
+- (concat result " -o ControlPath='tramp.%%r@%%h:%%p'"))
+- (setq result (concat result " -o ControlPath='tramp.%%C'"))))
+- (with-temp-buffer
+- (call-process "ssh" nil t nil "-o" "ControlPersist")
+- (goto-char (point-min))
+- (when (search-forward-regexp "missing.+argument" nil t)
+- (setq result (concat result " -o ControlPersist=no")))))))
+- result)
+- "Call ssh to detect whether it supports the Control* arguments.
+-Return a string to be used in `tramp-methods'."
+- :group 'tramp
+- :version "24.5"
+- :type 'string)
+-
+-;;;###tramp-autoload
+-(defcustom tramp-use-ssh-controlmaster-options
+- (not (zerop (length tramp-ssh-controlmaster-options)))
+- "Whether to use `tramp-ssh-controlmaster-options'."
+- :group 'tramp
+- :version "24.4"
+- :type 'boolean)
+-
+ (defcustom tramp-default-method
+ ;; An external copy method seems to be preferred, because it performs
+ ;; much better for large files, and it hasn't too serious delays
+@@ -376,9 +337,7 @@ Return a string to be used in `tramp-methods'."
+ (fboundp 'auth-source-search)
+ ;; ssh-agent is running.
+ (getenv "SSH_AUTH_SOCK")
+- (getenv "SSH_AGENT_PID")
+- ;; We could reuse the connection.
+- (> (length tramp-ssh-controlmaster-options) 0))
++ (getenv "SSH_AGENT_PID"))
+ "scp"
+ "ssh"))
+ ;; Fallback.
+@@ -560,7 +519,7 @@ if you need to change this."
+ :type 'string)
+
+ (defcustom tramp-login-prompt-regexp
+- ".*ogin\\( .*\\)?: *"
++ ".*\\(user\\|login\\)\\( .*\\)?: *"
+ "Regexp matching login-like prompts.
+ The regexp should match at end of buffer.
+
+@@ -2266,7 +2225,7 @@ Falls back to normal file name handler if no Tramp file name handler exists."
+ "Load Tramp file name handler, and perform OPERATION."
+ ;; Avoid recursive loading of tramp.el. `temporary-file-directory'
+ ;; does not exist in XEmacs, so we must use something else.
+- (let ((default-directory (or (symbol-value 'temporary-file-directory) "/")))
++ (let ((default-directory "/"))
+ (load "tramp" nil t))
+ (apply operation args)))
+
+@@ -3240,7 +3199,7 @@ User is always nil."
+ t)))
+
+ (defun tramp-handle-make-symbolic-link
+- (filename linkname &optional ok-if-already-exists)
++ (filename linkname &optional _ok-if-already-exists)
+ "Like `make-symbolic-link' for Tramp files."
+ (with-parsed-tramp-file-name
+ (if (tramp-tramp-file-p filename) filename linkname) nil
diff -Nru emacs24-24.5+1/debian/patches/series emacs24-24.5+1/debian/patches/series
--- emacs24-24.5+1/debian/patches/series 2015-10-18 10:29:18.000000000 -0700
+++ emacs24-24.5+1/debian/patches/series 2016-01-10 12:17:28.000000000 -0700
@@ -7,3 +7,4 @@
0007-Don-t-try-to-build-src-macuvs.h-via-IVD_Sequences.tx.patch
0008-Emacs-won-t-assume-grep-supports-GREP_OPTIONS.patch
0009-Emacs-should-no-longer-hang-during-large-yanks.patch
+0010-Emacs-should-no-longer-hang-when-loading-TRAMP.patch
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