[PATCH 2/8] Do not use VISUAL editor on dumb terminals

Refuse to use $VISUAL and fall back to $EDITOR if TERM is unset
or set to "dumb".  Traditionally, VISUAL is set to a screen
editor and EDITOR to a line-based editor, which should be more
useful in that situation.

vim, for example, is happy to assume a terminal supports ANSI
sequences even if TERM is dumb (e.g., when running from a text
editor like Acme).  git already refuses to fall back to vi on a
dumb terminal if GIT_EDITOR, core.editor, VISUAL, and EDITOR are
unset, but without this patch, that check is suppressed by
VISUAL=vi.

Signed-off-by: Jonathan Nieder <redacted>
---
This patch eases my discomfort about the error message a little.  It
is not actually needed to support any ways of working I engage in.

If stdout is redirected, this is probably still making the wrong
choice; isatty(STDOUT_FILENO) might be a more useful datum to use.
But it does not seem worth complicating the logic further.

 editor.c |   12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/editor.c b/editor.c
index 941c0b2..3f13751 100644
--- a/editor.c
+++ b/editor.c

@@ -4,19 +4,19 @@
 
 int launch_editor(const char *path, struct strbuf *buffer, const char *const *env)
 {
-	const char *editor, *terminal;
+	const char *editor = getenv("GIT_EDITOR");
+	const char *terminal = getenv("TERM");
+	int terminal_is_dumb = !terminal || !strcmp(terminal, "dumb");
 
-	editor = getenv("GIT_EDITOR");
 	if (!editor && editor_program)
 		editor = editor_program;
-	if (!editor)
+	if (!editor && !terminal_is_dumb)
 		editor = getenv("VISUAL");
 	if (!editor)
 		editor = getenv("EDITOR");
 
-	terminal = getenv("TERM");
-	if (!editor && (!terminal || !strcmp(terminal, "dumb")))
-		return error("Terminal is dumb but no VISUAL nor EDITOR defined.");
+	if (!editor && terminal_is_dumb)
+		return error("terminal is dumb, but EDITOR unset");
 
 	if (!editor)
 		editor = "vi";

-- 
1.6.5.2