diff: respect MIN_BLOCK_LENGTH for last block

Currently, MIN_BLOCK_LENGTH is only checked when diff encounters a line
that does not belong to the current block. In particular, this means
that MIN_BLOCK_LENGTH is not checked after all lines are encountered.

Perform that check.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/diff.c b/diff.c
index 23311f9c006a93d6691b9b2202ec24906047257f..f598d8a3a04c5125e2bbd758e518c79b1ba25a18 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -861,6 +861,26 @@ static int shrink_potential_moved_blocks(struct moved_entry **pmb,
        return rp + 1;
 }
 
+/*
+ * If o->color_moved is COLOR_MOVED_PLAIN, this function does nothing.
+ *
+ * Otherwise, if the last block has fewer lines than
+ * COLOR_MOVED_MIN_BLOCK_LENGTH, unset DIFF_SYMBOL_MOVED_LINE on all lines in
+ * that block.
+ *
+ * The last block consists of the (n - block_length)'th line up to but not
+ * including the nth line.
+ */
+static void adjust_last_block(struct diff_options *o, int n, int block_length)
+{
+       int i;
+       if (block_length >= COLOR_MOVED_MIN_BLOCK_LENGTH ||
+           o->color_moved == COLOR_MOVED_PLAIN)
+               return;
+       for (i = 1; i < block_length + 1; i++)
+               o->emitted_symbols->buf[n - i].flags &= ~DIFF_SYMBOL_MOVED_LINE;
+}
+
 /* Find blocks of moved code, delegate actual coloring decision to helper */
 static void mark_color_as_moved(struct diff_options *o,
                                struct hashmap *add_lines,
@@ -896,13 +916,7 @@ static void mark_color_as_moved(struct diff_options *o,
                }
 
                if (!match) {
-                       if (block_length < COLOR_MOVED_MIN_BLOCK_LENGTH &&
-                           o->color_moved != COLOR_MOVED_PLAIN) {
-                               for (i = 1; i < block_length + 1; i++) {
-                                       l = &o->emitted_symbols->buf[n - i];
-                                       l->flags &= ~DIFF_SYMBOL_MOVED_LINE;
-                               }
-                       }
+                       adjust_last_block(o, n, block_length);
                        pmb_nr = 0;
                        block_length = 0;
                        continue;
@@ -944,6 +958,7 @@ static void mark_color_as_moved(struct diff_options *o,
                if (flipped_block)
                        l->flags |= DIFF_SYMBOL_MOVED_LINE_ALT;
        }
+       adjust_last_block(o, n, block_length);
 
        free(pmb);
 }

diff --git a/t/t4015-diff-whitespace.sh b/t/t4015-diff-whitespace.sh
index c3b697411ab16a0dc21ce7579046765ccbeddfbd..6ae62a6bf6bf60943486adbc7cb27b9ee586f312 100755 (executable)
--- a/t/t4015-diff-whitespace.sh
+++ b/t/t4015-diff-whitespace.sh
@@ -1382,6 +1382,43 @@ EOF
        test_cmp expected actual
 '
 
+test_expect_success '--color-moved block at end of diff output respects MIN_BLOCK_LENGTH' '
+       git reset --hard &&
+       >bar &&
+       cat <<-\EOF >foo &&
+       irrelevant_line
+       line1
+       EOF
+       git add foo bar &&
+       git commit -m x &&
+
+       cat <<-\EOF >bar &&
+       line1
+       EOF
+       cat <<-\EOF >foo &&
+       irrelevant_line
+       EOF
+
+       git diff HEAD --color-moved=zebra --no-renames |
+               grep -v "index" |
+               test_decode_color >actual &&
+       cat >expected <<-\EOF &&
+       <BOLD>diff --git a/bar b/bar<RESET>
+       <BOLD>--- a/bar<RESET>
+       <BOLD>+++ b/bar<RESET>
+       <CYAN>@@ -0,0 +1 @@<RESET>
+       <GREEN>+<RESET><GREEN>line1<RESET>
+       <BOLD>diff --git a/foo b/foo<RESET>
+       <BOLD>--- a/foo<RESET>
+       <BOLD>+++ b/foo<RESET>
+       <CYAN>@@ -1,2 +1 @@<RESET>
+        irrelevant_line<RESET>
+       <RED>-line1<RESET>
+       EOF
+
+       test_cmp expected actual
+'
+
 test_expect_success 'move detection with submodules' '
        test_create_repo bananas &&
        echo ripe >bananas/recipe &&