add-patch: allow interfile navigation when selecting hunks

After deciding on all hunks in a file, the interactive session
advances automatically to the next file if there is another,
or the process ends.

Now using the `--no-auto-advance` flag with `--patch`, the process
does not advance automatically. A user can choose to go to the next
file by pressing '>' or the previous file by pressing '<', before or
after deciding on all hunks in the current file.

After all hunks have been decided in a file, the user can still
rework with the file by applying the options available in the permit
set for that hunk, and after all the decisions, the user presses 'q'
to submit.
After all hunks have been decided, the user can press '?' which will
show the hunk selection summary in the help patch remainder text
including the total hunks, number of hunks marked for use and number
of hunks marked for skip.

This feature is enabled by passing the `--no-auto-advance` flag
to `--patch` option of the subcommands add, stash, reset,
and checkout.

Signed-off-by: Abraham Samuel Adekunle <abrahamadekunle50@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: devdekunle

add-patch.c

@@ -1418,7 +1418,10 @@ N_("j - go to the next undecided hunk, roll over at the bottom\n"
    "e - manually edit the current hunk\n"
    "p - print the current hunk\n"
    "P - print the current hunk using the pager\n"
-   "? - print help\n");
+   "> - go to the next file, roll over at the bottom\n"
+   "< - go to the previous file, roll over at the top\n"
+   "? - print help\n"
+   "HUNKS SUMMARY - Hunks: %d, USE: %d, SKIP: %d\n");
 
 static void apply_patch(struct add_p_state *s, struct file_diff *file_diff)
 {
@@ -1483,6 +1486,7 @@ static ssize_t patch_update_file(struct add_p_state *s, size_t idx)
 	char ch;
 	int colored = !!s->colored.len, use_pager = 0;
 	enum prompt_mode_type prompt_mode_type;
+	int all_decided = 0;
 	struct file_diff *file_diff = s->file_diff + idx;
 	ssize_t patch_update_resp = (ssize_t)idx;
 
@@ -1501,7 +1505,9 @@ static ssize_t patch_update_file(struct add_p_state *s, size_t idx)
 			ALLOW_GOTO_NEXT_UNDECIDED_HUNK = 1 << 3,
 			ALLOW_SEARCH_AND_GOTO = 1 << 4,
 			ALLOW_SPLIT = 1 << 5,
-			ALLOW_EDIT = 1 << 6
+			ALLOW_EDIT = 1 << 6,
+			ALLOW_GOTO_PREVIOUS_FILE = 1 << 7,
+			ALLOW_GOTO_NEXT_FILE = 1 << 8
 		} permitted = 0;
 
 		if (hunk_index >= file_diff->hunk_nr)
@@ -1533,8 +1539,12 @@ static ssize_t patch_update_file(struct add_p_state *s, size_t idx)
 		/* Everything decided? */
 		if (undecided_previous < 0 && undecided_next < 0 &&
 		    hunk->use != UNDECIDED_HUNK) {
-				patch_update_resp++;
-				break;
+				if (!s->s.auto_advance)
+					all_decided = 1;
+				else {
+					patch_update_resp++;
+					break;
+				}
 		}
 		strbuf_reset(&s->buf);
 		if (file_diff->hunk_nr) {
@@ -1583,6 +1593,14 @@ static ssize_t patch_update_file(struct add_p_state *s, size_t idx)
 				permitted |= ALLOW_EDIT;
 				strbuf_addstr(&s->buf, ",e");
 			}
+			if (!s->s.auto_advance && s->file_diff_nr > 1) {
+				permitted |= ALLOW_GOTO_NEXT_FILE;
+				strbuf_addstr(&s->buf, ",>");
+			}
+			if (!s->s.auto_advance && s->file_diff_nr > 1) {
+				permitted |= ALLOW_GOTO_PREVIOUS_FILE;
+				strbuf_addstr(&s->buf, ",<");
+			}
 			strbuf_addstr(&s->buf, ",p,P");
 		}
 		if (file_diff->deleted)
@@ -1653,6 +1671,28 @@ static ssize_t patch_update_file(struct add_p_state *s, size_t idx)
 		} else if (ch == 'q') {
 			patch_update_resp = -1;
 			break;
+		} else if (!s->s.auto_advance && s->answer.buf[0] == '>') {
+			if (permitted & ALLOW_GOTO_NEXT_FILE) {
+				if (patch_update_resp == s->file_diff_nr - 1)
+					patch_update_resp = 0;
+				else
+					patch_update_resp++;
+				break;
+			} else {
+				err(s, _("No next file"));
+				continue;
+			}
+		} else if (!s->s.auto_advance && s->answer.buf[0] == '<') {
+			if (permitted & ALLOW_GOTO_PREVIOUS_FILE) {
+				if (patch_update_resp == 0)
+					patch_update_resp = s->file_diff_nr - 1;
+				else
+					patch_update_resp--;
+				break;
+			} else {
+				err(s, _("No previous file"));
+				continue;
+			}
 		} else if (s->answer.buf[0] == 'K') {
 			if (permitted & ALLOW_GOTO_PREVIOUS_HUNK)
 				hunk_index = dec_mod(hunk_index,
@@ -1798,6 +1838,18 @@ static ssize_t patch_update_file(struct add_p_state *s, size_t idx)
 				 * commands shown in the prompt that are not
 				 * always available.
 				 */
+				if (all_decided && !strncmp(p, "HUNKS SUMMARY", 13)) {
+					int total = file_diff->hunk_nr, used = 0, skipped = 0;
+
+					for (i = 0; i < file_diff->hunk_nr; i++) {
+						if (file_diff->hunk[i].use == USE_HUNK)
+							used += 1;
+						if (file_diff->hunk[i].use == SKIP_HUNK)
+							skipped += 1;
+					}
+					color_fprintf_ln(stdout, s->s.help_color, _(p),
+							 total, used, skipped);
+				}
 				if (*p != '?' && !strchr(s->buf.buf, *p))
 					continue;
 
@@ -1810,7 +1862,8 @@ static ssize_t patch_update_file(struct add_p_state *s, size_t idx)
 		}
 	}
 
-	apply_patch(s, file_diff);
+	if (s->s.auto_advance)
+		apply_patch(s, file_diff);
 
 	putchar('\n');
 	return patch_update_resp;
@@ -1874,6 +1927,9 @@ int run_add_p(struct repository *r, enum add_p_mode mode,
 			break;
 		i = (size_t)patch_update_resp;
     }
+	if (!s.s.auto_advance)
+		for (i = 0; i < s.file_diff_nr; i++)
+			apply_patch(&s, s.file_diff + i);
 
 	if (s.file_diff_nr == 0)
 		err(&s, _("No changes."));

t/t3701-add-interactive.sh

@@ -1441,5 +1441,105 @@ test_expect_success 'EOF quits' '
 	test_grep file out &&
 	test_grep ! file2 out
 '
+for cmd in add checkout reset "stash save" "stash push"
+do
+	test_expect_success "$cmd rejects invalid --no-auto-advance options" '
+		test_must_fail git $cmd --no-auto-advance 2>actual &&
+		test_grep -E  "requires .*--(interactive|patch)" actual
+	'
+done
+
+test_expect_success 'manual advance (">") moves to next file with --no-auto-advance' '
+	git reset --hard &&
+	echo line1 >first-file &&
+	echo line2 >second-file &&
+	git add -A &&
+	git commit -m initial >/dev/null 2>&1 &&
+	echo change_first >>first-file &&
+	echo change_second >>second-file &&
+
+	printf ">\nq\n" | git add -p --no-auto-advance >output.test 2>&1 &&
+	test_grep  -E "(a|b)/second-file" output.test
+'
+
+test_expect_success 'select n on a hunk, go to another file, come back and change to y stages' '
+	git reset --hard &&
+	echo one >f1 &&
+	echo one >f2 &&
+	git add -A &&
+	git commit -m initial >/dev/null 2>&1 &&
+	echo change1 >>f1 &&
+	echo change2 >>f2 &&
+
+	printf "n\n>\n<\ny\nq\n" | git add -p --no-auto-advance >output.staged 2>&1 &&
+	git diff --cached --name-only >staged &&
+	test_grep -E "(a/f1)" output.staged
+'
+
+test_expect_success 'select y on a hunk, go to another file, come back and change to n does not stage' '
+	git reset --hard &&
+	echo one >f1 &&
+	echo one >f2 &&
+	git add -A &&
+	git commit -m initial >/dev/null 2>&1 &&
+	echo change1 >>f1 &&
+	echo change2 >>f2 &&
+
+	printf "y\n>\n<\nn\nq\n" | git add -p --no-auto-advance >output.unstaged 2>&1 &&
+	git diff --cached --name-only >staged &&
+	test_must_be_empty staged
+'
+
+test_expect_success 'deciding all hunks in a file does not auto advance' '
+	git reset --hard &&
+	echo line >stay &&
+	echo line >other &&
+	git add -A &&
+	git commit -m initial >/dev/null 2>&1 &&
+	echo change >>stay &&
+	echo change >>other &&
+	test_write_lines y | git add -p --no-auto-advance >raw-output 2>&1 &&
+	test_grep "(1/1) Stage this hunk (was: y)" raw-output &&
+	test_grep ! "diff --git a/stay b/stay" raw-output
+'
+test_expect_success 'HUNKS SUMMARY does not show in help text when there are undecided hunks' '
+	git reset --hard &&
+	test_write_lines 1 2 3 4 5 6 7 8 9 >f &&
+	git add f &&
+	git commit -m initial >/dev/null 2>&1 &&
+	test_write_lines 1 X 3 4 Y 6 7 Z 9 >f &&
+	test_write_lines s y n | git add -p --no-auto-advance >raw-nostat 2>&1 &&
+	test_grep ! "HUNKS SUMMARY - Hunks: " raw-nostat
+'
+
+test_expect_success 'help text shows HUNK SUMMARY when all hunks have been decided' '
+	git reset --hard &&
+	test_write_lines 1 2 3 4 5 6 7 8 9 >f2 &&
+	git add f2 &&
+	git commit -m initial >/dev/null 2>&1 &&
+	test_write_lines 1 X 3 4 Y 6 7 Z 9 >f2 &&
+	printf "s\ny\nn\ny\n?\n" | git add -p --no-auto-advance >raw-stat 2>&1 &&
+	test_grep "HUNKS SUMMARY - Hunks: 3, USE: 2, SKIP: 1" raw-stat
+'
+
+test_expect_success 'selective staging across multiple files with --no-advance' '
+	git reset --hard &&
+	test_write_lines 1 2 3 4 5 6 7 8 9 >a.file &&
+	test_write_lines 1 2 3 4 5 6 7 8 9 >b.file &&
+	test_write_lines 1 2 3 4 5 6 7 8 9 >c.file &&
+	git add -A &&
+	git commit -m initial >/dev/null 2>&1 &&
+	test_write_lines 1 A2 3 4 A5 6 7 8 9 >a.file &&
+	test_write_lines 1 2 B3 4 5 6 7 B8 9 >b.file &&
+	test_write_lines C1 2 3 4 5 C6 7 8 9 >c.file &&
+	printf "s\ny\nn\n>\ns\nn\ny\n>\ns\ny\ny\nq\n" | git add -p --no-auto-advance >output.index 2>&1 &&
+	git diff --cached >staged.diff &&
+	test_grep "+A2" staged.diff &&
+	test_grep ! "+A5" staged.diff &&
+	test_grep "+B8" staged.diff &&
+	test_grep ! "+B3" staged.diff &&
+	test_grep "+C1" staged.diff &&
+	test_grep "+C6" staged.diff
+'
 
 test_done