config: handle lack of newline at end of file better

The config parsing routines use the static global
'config_file' to store the FILE* pointing to the current
config file being parsed. The function get_next_char()
automatically converts an EOF on this file to a newline for
the convenience of its callers, and it sets config_file to
NULL to indicate that EOF was reached.

This throws away useful information, though, since some
routines want to call ftell on 'config_file' to find out
exactly _where_ the routine ended. In the case of a key
ending at EOF boundary, we ended up segfaulting in some
cases (changing that key or adding another key in its
section), or failing to provide the necessary newline
(adding a new section).

This patch adds a new flag to indicate EOF and uses that
instead of setting config_file to NULL. It also makes sure
to add newlines where necessary for truncated input. All
three included tests fail without the patch.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 37 insertions, 0 deletions

diff --git a/t/t1303-wacky-config.sh b/t/t1303-wacky-config.sh
new file mode 100755
index 0000000000..99985dcd79
--- /dev/null
+++ b/t/t1303-wacky-config.sh
@@ -0,0 +1,37 @@
+#!/bin/sh
+
+test_description='Test wacky input to git config'
+. ./test-lib.sh
+
+setup() {
+	(printf "[section]\n" &&
+	printf "  key = foo") >.git/config
+}
+
+check() {
+	echo "$2" >expected
+	git config --get "$1" >actual
+	git diff actual expected
+}
+
+test_expect_success 'modify same key' '
+	setup &&
+	git config section.key bar &&
+	check section.key bar
+'
+
+test_expect_success 'add key in same section' '
+	setup &&
+	git config section.other bar &&
+	check section.key foo &&
+	check section.other bar
+'
+
+test_expect_success 'add key in different section' '
+	setup &&
+	git config section2.key bar &&
+	check section.key foo &&
+	check section2.key bar
+'
+
+test_done