From 1a947dd65de23e3d4ad1c2da468c5c4e764286a3 Mon Sep 17 00:00:00 2001
From: Allen Li <darkfeline@felesatra.moe>
Date: Tue, 5 Dec 2017 13:01:24 -0800
Subject: [PATCH] Add option to configure comint TERM

* doc/emacs/misc.texi (Shell Options): Document new option
* lisp/comint.el (comint-terminfo-terminal): Add new option
(comint-term-environment): Add new function for setting terminal options
(comint-exec-1): Use comint-term-environment
* lisp/progmodes/compile.el (compilation-start): Use comint-term-environment
---
 doc/emacs/misc.texi       |  8 ++++++++
 lisp/comint.el            | 35 ++++++++++++++++++++++-------------
 lisp/progmodes/compile.el |  8 +-------
 3 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/doc/emacs/misc.texi b/doc/emacs/misc.texi
index 6ad5fbafdd..1eaa2160c9 100644
--- a/doc/emacs/misc.texi
+++ b/doc/emacs/misc.texi
@@ -1396,6 +1396,14 @@ Shell Options
 (@code{shell-pushd-dunique}).  The values you choose should match the
 underlying shell, of course.
 
+@vindex comint-terminfo-terminal
+Comint sets the @env{TERM} environment variable to a safe value, but
+this value may not reflect the full features of comint.  For example,
+color is disabled for some applications that use @env{TERM} to
+determine if color is supported.  On systems that use terminfo, you
+can configure @code{comint-terminfo-terminal} to a terminal that is
+present in your system's terminfo database.
+
 @node Terminal emulator
 @subsection Emacs Terminal Emulator
 @findex term
diff --git a/lisp/comint.el b/lisp/comint.el
index aa7dab28f3..433eeb1fb2 100644
--- a/lisp/comint.el
+++ b/lisp/comint.el
@@ -458,6 +458,11 @@ comint-exec-hook
   :type 'hook
   :group 'comint)
 
+(defcustom comint-terminfo-terminal "dumb"
+  "Value to use for TERM when the system uses terminfo."
+  :type 'string
+  :group 'comint)
+
 (defvar comint-mode-map
   (let ((map (make-sparse-keymap)))
     ;; Keys:
@@ -816,19 +821,7 @@ comint-exec
 (defun comint-exec-1 (name buffer command switches)
   (let ((process-environment
 	 (nconc
-	  ;; If using termcap, we specify `emacs' as the terminal type
-	  ;; because that lets us specify a width.
-	  ;; If using terminfo, we specify `dumb' because that is
-	  ;; a defined terminal type.  `emacs' is not a defined terminal type
-	  ;; and there is no way for us to define it here.
-	  ;; Some programs that use terminfo get very confused
-	  ;; if TERM is not a valid terminal type.
-	  ;; ;; There is similar code in compile.el.
-	  (if (and (boundp 'system-uses-terminfo) system-uses-terminfo)
-	      (list "TERM=dumb" "TERMCAP="
-		    (format "COLUMNS=%d" (window-width)))
-	    (list "TERM=emacs"
-		  (format "TERMCAP=emacs:co#%d:tc=unknown:" (window-width))))
+          (comint-term-environment)
 	  (list (format "INSIDE_EMACS=%s,comint" emacs-version))
 	  process-environment))
 	(default-directory
@@ -857,6 +850,22 @@ comint-exec-1
 	(set-process-coding-system proc decoding encoding))
     proc))
 
+(defun comint-term-environment ()
+  "Return an environment variable list for terminal configuration."
+  ;; If using termcap, we specify `emacs' as the terminal type
+  ;; because that lets us specify a width.
+  ;; If using terminfo, we default to `dumb' because that is
+  ;; a defined terminal type.  `emacs' is not a defined terminal type
+  ;; and there is no way for us to define it here.
+  ;; Some programs that use terminfo get very confused
+  ;; if TERM is not a valid terminal type.
+  (if (and (boundp 'system-uses-terminfo) system-uses-terminfo)
+      (list (format "TERM=%s" comint-terminfo-terminal)
+            "TERMCAP="
+            (format "COLUMNS=%d" (window-width)))
+    (list "TERM=emacs"
+          (format "TERMCAP=emacs:co#%d:tc=unknown:" (window-width)))))
+
 (defun comint-nonblank-p (str)
   "Return non-nil if STR contains non-whitespace syntax."
   (not (string-match "\\`\\s *\\'" str)))
diff --git a/lisp/progmodes/compile.el b/lisp/progmodes/compile.el
index 4cce47e5d8..c68001d236 100644
--- a/lisp/progmodes/compile.el
+++ b/lisp/progmodes/compile.el
@@ -1746,13 +1746,7 @@ compilation-start
       (let ((process-environment
 	     (append
 	      compilation-environment
-	      (if (if (boundp 'system-uses-terminfo);`If' for compiler warning.
-		      system-uses-terminfo)
-		  (list "TERM=dumb" "TERMCAP="
-			(format "COLUMNS=%d" (window-width)))
-		(list "TERM=emacs"
-		      (format "TERMCAP=emacs:co#%d:tc=unknown:"
-			      (window-width))))
+              (comint-term-environment)
 	      (list (format "INSIDE_EMACS=%s,compile" emacs-version))
 	      (copy-sequence process-environment))))
 	(set (make-local-variable 'compilation-arguments)
-- 
2.15.1