[PATCH] add--interactive: fix missing file prompt for patch mode with "-i"

[Jeff King]

When invoked as "git add -i", each menu interactive menu
option prompts the user to select a list of files. This
includes the "patch" option, which gets the list before
starting the hunk-selection loop.

As "git add -p", it behaves differently, and jumps straight
to the hunk selection loop.

Since 0539d5e6d (i18n: add--interactive: mark patch prompt
for translation, 2016-12-14), the "add -i" case mistakenly
jumps to straight to the hunk-selection loop. Prior to that
commit the distinction between the two cases was managed by
the $patch_mode variable. That commit used $patch_mode for
something else, and moved the old meaning to the "$cmd"
variable.  But it forgot to update the $patch_mode check
inside patch_update_cmd() which controls the file-list
behavior.

The simplest fix would be to change that line to check $cmd.
But while we're here, let's use a less obscure name for this
flag: $patch_mode_only, a boolean which tells whether we are
in full-interactive mode or only in patch-mode.

Reported-by: Henrik Grubbström <gru...@grubba.org>
Signed-off-by: Jeff King <p...@peff.net>
---
 git-add--interactive.perl  |  8 ++++----
 t/t3701-add-interactive.sh | 18 ++++++++++++++++++
 2 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/git-add--interactive.perl b/git-add--interactive.perl
index 982593c89..f5c816e27 100755
--- a/git-add--interactive.perl
+++ b/git-add--interactive.perl
@@ -92,7 +92,7 @@ sub colored {
 }
 
 # command line options
-my $cmd;
+my $patch_mode_only;
 my $patch_mode;
 my $patch_mode_revision;
 
@@ -1299,7 +1299,7 @@ sub patch_update_cmd {
                }
                return 0;
        }
-       if ($patch_mode) {
+       if ($patch_mode_only) {
                @them = @mods;
        }
        else {
@@ -1721,7 +1721,7 @@ sub process_args {
                die sprintf(__("invalid argument %s, expecting --"),
                               $arg) unless $arg eq "--";
                %patch_mode_flavour = %{$patch_modes{$patch_mode}};
-               $cmd = 1;
+               $patch_mode_only = 1;
        }
        elsif ($arg ne "--") {
                die sprintf(__("invalid argument %s, expecting --"), $arg);
@@ -1758,7 +1758,7 @@ sub main_loop {
 
 process_args();
 refresh();
-if ($cmd) {
+if ($patch_mode_only) {
        patch_update_cmd();
 }
 else {
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index 5ffe78e92..aaa258daa 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -394,4 +394,22 @@ test_expect_success 'diffs can be colorized' '
        grep "$(printf "\\033")" output
 '
 
+test_expect_success 'patch-mode via -i prompts for files' '
+       git reset --hard &&
+
+       echo one >file &&
+       echo two >test &&
+       git add -i <<-\EOF &&
+       patch
+       test
+
+       y
+       quit
+       EOF
+
+       echo test >expect &&
+       git diff --cached --name-only >actual &&
+       test_cmp expect actual
+'
+
 test_done
-- 
2.12.0.367.gb23790f66