From: James Coglan <jcog...@gmail.com>
Currently, when we display a merge whose first parent is already present
in a column to the left of the merge commit, we display the first parent
as a veritcal pipe `|` in the GRAPH_POST_MERGE line and then immediately
enter the GRAPH_COLLAPSING state. The first-parent line tracks to the
left and all the other parent lines follow it; this creates a "kink" in
those lines:
| *---.
| |\ \ \
|/ / / /
| | | *
This change tidies the display of such commits such that if the first
parent appears to the left of the merge, we render it as a `/` and the
second parent as a `|`. This reduces the horizontal and vertical space
needed to render the merge, and makes the resulting lines easier to
read.
| *-.
|/|\ \
| | | *
If the first parent is separated from the merge by several columns, a
horizontal line is drawn in a similar manner to how the GRAPH_COLLAPSING
state displays the line.
| | | *-.
| |_|/|\ \
|/| | | | *
This effect is applied to both "normal" two-parent merges, and to
octopus merges. It also reduces the vertical space needed for pre-commit
lines, as the merge occupies one less column than usual.
Before: After:
| * | *
| |\ | |\
| | \ | * \
| | \ |/|\ \
| *-. \
| |\ \ \
Signed-off-by: James Coglan <jcog...@gmail.com>
---
graph.c | 125 +++++++++++++++++++++++++++--------
t/t4214-log-graph-octopus.sh | 10 ++-
t/t4215-log-skewed-merges.sh | 42 ++++++++++++
3 files changed, 143 insertions(+), 34 deletions(-)
create mode 100755 t/t4215-log-skewed-merges.sh
diff --git a/graph.c b/graph.c
index 98e8777db4..9136173e03 100644
--- a/graph.c
+++ b/graph.c
@@ -183,6 +183,20 @@ struct git_graph {
* previous commit.
*/
int prev_commit_index;
+ /*
+ * Which layout variant to use to display merge commits. If the
+ * commit's first parent is known to be in a column to the left of the
+ * merge, then this value is 0 and we use the layout on the left.
+ * Otherwise, the value is 1 and the layout on the right is used. This
+ * field tells us how many columns the first parent occupies.
+ *
+ * 0) 1)
+ *
+ * | | | *-. | | *---.
+ * | |_|/|\ \ | | |\ \ \
+ * |/| | | | | | | | | | *
+ */
+ int merge_layout;
/*
* The maximum number of columns that can be stored in the columns
* and new_columns arrays. This is also half the number of entries
@@ -294,6 +308,7 @@ struct git_graph *graph_init(struct rev_info *opt)
graph->prev_state = GRAPH_PADDING;
graph->commit_index = 0;
graph->prev_commit_index = 0;
+ graph->merge_layout = 0;
graph->num_columns = 0;
graph->num_new_columns = 0;
graph->mapping_size = 0;
@@ -453,9 +468,11 @@ static int graph_find_new_column_by_commit(struct
git_graph *graph,
}
static void graph_insert_into_new_columns(struct git_graph *graph,
- struct commit *commit)
+ struct commit *commit,
+ int idx)
{
int i = graph_find_new_column_by_commit(graph, commit);
+ int mapping_idx;
/*
* If the commit is not already in the new_columns array, then add it
@@ -467,8 +484,26 @@ static void graph_insert_into_new_columns(struct git_graph
*graph,
graph->new_columns[i].color = graph_find_commit_color(graph,
commit);
}
- graph->mapping[graph->width] = i;
- graph->width += 2;
+ if (graph->num_parents > 1 && idx > -1 && graph->merge_layout == -1) {
+ /*
+ * If this is the first parent of a merge, choose a layout for
+ * the merge line based on whether the parent appears in a
+ * column to the left of the merge
+ */
+ int dist, shift;
+
+ dist = idx - i;
+ shift = (dist > 1) ? 2 * dist - 3 : 1;
+
+ graph->merge_layout = (dist > 0) ? 0 : 1;
+ mapping_idx = graph->width + (graph->merge_layout - 1) * shift;
+ graph->width += 2 * graph->merge_layout;
+ } else {
+ mapping_idx = graph->width;
+ graph->width += 2;
+ }
+
+ graph->mapping[mapping_idx] = i;
}
static void graph_update_columns(struct git_graph *graph)
@@ -534,6 +569,7 @@ static void graph_update_columns(struct git_graph *graph)
if (col_commit == graph->commit) {
seen_this = 1;
graph->commit_index = i;
+ graph->merge_layout = -1;
for (parent = first_interesting_parent(graph);
parent;
parent = next_interesting_parent(graph, parent)) {
@@ -546,7 +582,7 @@ static void graph_update_columns(struct git_graph *graph)
!is_commit_in_columns) {
graph_increment_column_color(graph);
}
- graph_insert_into_new_columns(graph,
parent->item);
+ graph_insert_into_new_columns(graph,
parent->item, i);
}
/*
* We always need to increment graph->width by at
@@ -557,7 +593,7 @@ static void graph_update_columns(struct git_graph *graph)
if (graph->num_parents == 0)
graph->width += 2;
} else {
- graph_insert_into_new_columns(graph, col_commit);
+ graph_insert_into_new_columns(graph, col_commit, -1);
}
}
@@ -569,10 +605,36 @@ static void graph_update_columns(struct git_graph *graph)
graph->mapping_size--;
}
+static int graph_num_expansion_rows(struct git_graph *graph)
+{
+ /*
+ * Normally, we need two expansion rows for each dashed parent line from
+ * an octopus merge:
+ *
+ * | *
+ * | |\
+ * | | \
+ * | | \
+ * | *-. \
+ * | |\ \ \
+ *
+ * If the merge is skewed to the left, then its parents occupy one less
+ * column, and we don't need as many expansion rows to route around it;
+ * in some cases that means we don't need any expansion rows at all:
+ *
+ * | *
+ * | |\
+ * | * \
+ * |/|\ \
+ */
+ return (graph->num_parents + graph->merge_layout - 3) * 2;
+}
+
static int graph_needs_pre_commit_line(struct git_graph *graph)
{
return graph->num_parents >= 3 &&
- graph->commit_index < (graph->num_columns - 1);
+ graph->commit_index < (graph->num_columns - 1) &&
+ graph->expansion_row < graph_num_expansion_rows(graph);
}
void graph_update(struct git_graph *graph, struct commit *commit)
@@ -722,7 +784,6 @@ static void graph_output_skip_line(struct git_graph *graph,
struct strbuf *sb)
static void graph_output_pre_commit_line(struct git_graph *graph,
struct strbuf *sb)
{
- int num_expansion_rows;
int i, seen_this;
/*
@@ -733,14 +794,13 @@ static void graph_output_pre_commit_line(struct git_graph
*graph,
* We need 2 extra rows for every parent over 2.
*/
assert(graph->num_parents >= 3);
- num_expansion_rows = (graph->num_parents - 2) * 2;
/*
* graph->expansion_row tracks the current expansion row we are on.
* It should be in the range [0, num_expansion_rows - 1]
*/
assert(0 <= graph->expansion_row &&
- graph->expansion_row < num_expansion_rows);
+ graph->expansion_row < graph_num_expansion_rows(graph));
/*
* Output the row
@@ -782,7 +842,7 @@ static void graph_output_pre_commit_line(struct git_graph
*graph,
* and move to state GRAPH_COMMIT if necessary
*/
graph->expansion_row++;
- if (graph->expansion_row >= num_expansion_rows)
+ if (!graph_needs_pre_commit_line(graph))
graph_update_state(graph, GRAPH_COMMIT);
}
@@ -820,7 +880,7 @@ static void graph_draw_octopus_merge(struct git_graph
*graph, struct strbuf *sb)
* x 0 1 2 3
*
*/
- const int dashless_parents = 2;
+ const int dashless_parents = 3 - graph->merge_layout;
int dashful_parents = graph->num_parents - dashless_parents;
/*
@@ -828,9 +888,9 @@ static void graph_draw_octopus_merge(struct git_graph
*graph, struct strbuf *sb)
* above) but sometimes the first parent goes into an existing column,
* like this:
*
- * | *---.
- * | |\ \ \
- * |/ / / /
+ * | *-.
+ * |/|\ \
+ * | | | |
* x 0 1 2
*
* In which case the number of parents will be one greater than the
@@ -923,10 +983,15 @@ static void graph_output_commit_line(struct git_graph
*graph, struct strbuf *sb)
graph_update_state(graph, GRAPH_COLLAPSING);
}
+const char merge_chars[] = {'/', '|', '\\'};
+
static void graph_output_post_merge_line(struct git_graph *graph, struct
strbuf *sb)
{
int seen_this = 0;
- int i, j;
+ int i;
+
+ struct commit_list *first_parent = first_interesting_parent(graph);
+ int seen_parent = 0;
/*
* Output the post-merge row
@@ -949,30 +1014,34 @@ static void graph_output_post_merge_line(struct
git_graph *graph, struct strbuf
* new_columns and use those to format the
* edges.
*/
- struct commit_list *parents = NULL;
+ struct commit_list *parents = first_parent;
int par_column;
+ int idx = graph->merge_layout;
+ char c;
seen_this = 1;
- parents = first_interesting_parent(graph);
- assert(parents);
- par_column = graph_find_new_column_by_commit(graph,
parents->item);
- assert(par_column >= 0);
-
- strbuf_write_column(sb,
&graph->new_columns[par_column], '|');
- for (j = 0; j < graph->num_parents - 1; j++) {
- parents = next_interesting_parent(graph,
parents);
- assert(parents);
+
+ for (; parents; parents =
next_interesting_parent(graph, parents)) {
par_column =
graph_find_new_column_by_commit(graph, parents->item);
assert(par_column >= 0);
- strbuf_write_column(sb,
&graph->new_columns[par_column], '\\');
- strbuf_addch(sb, ' ');
+
+ c = merge_chars[idx];
+ strbuf_write_column(sb,
&graph->new_columns[par_column], c);
+ if (idx == 2)
+ strbuf_addch(sb, ' ');
+ else
+ idx++;
}
} else if (seen_this) {
strbuf_write_column(sb, col, '\\');
strbuf_addch(sb, ' ');
} else {
strbuf_write_column(sb, col, '|');
- strbuf_addch(sb, ' ');
+ if (graph->merge_layout != 0 || i !=
graph->commit_index - 1)
+ strbuf_addch(sb, seen_parent ? '_' : ' ');
}
+
+ if (col_commit == first_parent->item)
+ seen_parent = 1;
}
graph_pad_horizontally(graph, sb);
diff --git a/t/t4214-log-graph-octopus.sh b/t/t4214-log-graph-octopus.sh
index dab96c89aa..40f420877b 100755
--- a/t/t4214-log-graph-octopus.sh
+++ b/t/t4214-log-graph-octopus.sh
@@ -7,9 +7,8 @@ test_description='git log --graph of skewed left octopus merge.'
test_expect_success 'set up merge history' '
cat >expect.uncolored <<-\EOF &&
* left
- | *---. octopus-merge
- | |\ \ \
- |/ / / /
+ | *-. octopus-merge
+ |/|\ \
| | | * 4
| | * | 3
| | |/
@@ -21,9 +20,8 @@ test_expect_success 'set up merge history' '
EOF
cat >expect.colors <<-\EOF &&
* left
- <RED>|<RESET>
*<BLUE>-<RESET><BLUE>-<RESET><MAGENTA>-<RESET><MAGENTA>.<RESET> octopus-merge
- <RED>|<RESET> <RED>|<RESET><YELLOW>\<RESET> <BLUE>\<RESET>
<MAGENTA>\<RESET>
- <RED>|<RESET><RED>/<RESET> <YELLOW>/<RESET> <BLUE>/<RESET>
<MAGENTA>/<RESET>
+ <RED>|<RESET> *<MAGENTA>-<RESET><MAGENTA>.<RESET> octopus-merge
+ <RED>|<RESET><RED>/<RESET><YELLOW>|<RESET><BLUE>\<RESET>
<MAGENTA>\<RESET>
<RED>|<RESET> <YELLOW>|<RESET> <BLUE>|<RESET> * 4
<RED>|<RESET> <YELLOW>|<RESET> * <MAGENTA>|<RESET> 3
<RED>|<RESET> <YELLOW>|<RESET> <MAGENTA>|<RESET><MAGENTA>/<RESET>
diff --git a/t/t4215-log-skewed-merges.sh b/t/t4215-log-skewed-merges.sh
new file mode 100755
index 0000000000..cfaba40f97
--- /dev/null
+++ b/t/t4215-log-skewed-merges.sh
@@ -0,0 +1,42 @@
+#!/bin/sh
+
+test_description='git log --graph of skewed merges'
+
+. ./test-lib.sh
+
+test_expect_success 'setup left-skewed merge' '
+ git checkout --orphan _a && test_commit A &&
+ git branch _b &&
+ git branch _c &&
+ git branch _d &&
+ git branch _e &&
+ git checkout _b && test_commit B &&
+ git checkout _c && test_commit C &&
+ git checkout _d && test_commit D &&
+ git checkout _e && git merge --no-ff _d -m E &&
+ git checkout _a && git merge --no-ff _b _c _e -m F
+'
+
+cat > expect <<\EOF
+*---. F
+|\ \ \
+| | | * E
+| |_|/|
+|/| | |
+| | | * D
+| |_|/
+|/| |
+| | * C
+| |/
+|/|
+| * B
+|/
+* A
+EOF
+
+test_expect_success 'log --graph with left-skewed merge' '
+ git log --graph --pretty=tformat:%s | sed "s/ *$//" > actual &&
+ test_cmp expect actual
+'
+
+test_done
--
gitgitgadget
