Teach git var about GIT_EDITOR

Expose the command used by launch_editor() for scripts to use.
This should allow one to avoid searching for a proper editor
separately in each command.

git_editor(void) uses the logic to decide which editor to use
that used to live in launch_editor().  The function returns NULL
if there is no suitable editor; the caller is expected to issue
an error message when appropriate.

launch_editor() uses git_editor() and gives the error message the
same way as before when EDITOR is not set.

"git var GIT_EDITOR" gives the editor name, or an error message
when there is no appropriate one.

"git var -l" gives GIT_EDITOR=name only if there is an
appropriate editor.

Originally-submitted-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/var.c b/var.c
index dacbaab25..b502487e5 100644
--- a/var.c
+++ b/var.c
@@ -8,6 +8,16 @@
 
 static const char var_usage[] = "git var [-l | <variable>]";
 
+static const char *editor(int flag)
+{
+	const char *pgm = git_editor();
+
+	if (!pgm && flag & IDENT_ERROR_ON_NO_NAME)
+		die("Terminal is dumb, but EDITOR unset");
+
+	return pgm;
+}
+
 struct git_var {
 	const char *name;
 	const char *(*read)(int);
@@ -15,14 +25,18 @@ struct git_var {
 static struct git_var git_vars[] = {
 	{ "GIT_COMMITTER_IDENT", git_committer_info },
 	{ "GIT_AUTHOR_IDENT",   git_author_info },
+	{ "GIT_EDITOR", editor },
 	{ "", NULL },
 };
 
 static void list_vars(void)
 {
 	struct git_var *ptr;
+	const char *val;
+
 	for (ptr = git_vars; ptr->read; ptr++)
-		printf("%s=%s\n", ptr->name, ptr->read(0));
+		if ((val = ptr->read(0)))
+			printf("%s=%s\n", ptr->name, val);
 }
 
 static const char *read_var(const char *var)