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authorJames Coglan <jcoglan@gmail.com>2019-10-15 23:47:55 (GMT)
committerJunio C Hamano <gitster@pobox.com>2019-10-16 02:11:25 (GMT)
commitd62893ecc125767d44a194279bcaffa0d02d2572 (patch)
tree663e39919b1460afe1c0ecfecf47e9efc59e8271
parent0f0f389f12029b1c3745f8ed7aacfe6b2fc7a6cc (diff)
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graph: commit and post-merge lines for left-skewed merges
Following the introduction of "left-skewed" merges, which are merges whose first parent fuses with another edge to its left, we have some more edge cases to deal with in the display of commit and post-merge lines. The current graph code handles the following cases for edges appearing to the right of the commit (*) on commit lines. A 2-way merge is usually followed by vertical lines: | | | | * | | |\ \ An octopus merge (more than two parents) is always followed by edges sloping to the right: | | \ | | \ | *-. \ | *---. \ | |\ \ \ | |\ \ \ \ A 2-way merge is followed by a right-sloping edge if the commit line immediately follows a post-merge line for a commit that appears in the same column as the current commit, or any column to the left of that: | * | * | | |\ | |\ \ | * \ | | * \ | |\ \ | | |\ \ This commit introduces the following new cases for commit lines. If a 2-way merge skews to the left, then the edges to its right are always vertical lines, even if the commit follows a post-merge line: | | | | |\ | * | | * | |/| | |/| | A commit with 3 parents that skews left is followed by vertical edges: | | | | * | |/|\ \ If a 3-way left-skewed merge commit appears immediately after a post-merge line, then it may be followed the right-sloping edges, just like a 2-way merge that is not skewed. | |\ | * \ |/|\ \ Octopus merges with 4 or more parents that skew to the left will always be followed by right-sloping edges, because the existing columns need to expand around the merge. | | \ | *-. \ |/|\ \ \ On post-merge lines, usually all edges following the current commit slope to the right: | * | | | |\ \ \ However, if the commit is a left-skewed 2-way merge, the edges to its right remain vertical. We also need to display a space after the vertical line descending from the commit marker, whereas this line would normally be followed by a backslash. | * | | |/| | | If a left-skewed merge has more than 2 parents, then the edges to its right are still sloped as they bend around the edges introduced by the merge. | * | | |/|\ \ \ To handle these new cases, we need to know not just how many parents each commit has, but how many new columns it adds to the display; this quantity is recorded in the `edges_added` field for the current commit, and `prev_edges_added` field for the previous commit. Here, "column" refers to visual columns, not the logical columns of the `columns` array. This is because even if all the commit's parents end up fusing with existing edges, they initially introduce distinct edges in the commit and post-merge lines before those edges collapse. For example, a 3-way merge whose 2nd and 3rd parents fuse with existing edges still introduces 2 visual columns that affect the display of edges to their right. | | | \ | | *-. \ | | |\ \ \ | |_|/ / / |/| | / / | | |/ / | |/| | | | | | This merge does not introduce any *logical* columns; there are 4 edges before and after this commit once all edges have collapsed. But it does initially introduce 2 new edges that need to be accommodated by the edges to their right. Signed-off-by: James Coglan <jcoglan@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r--graph.c63
-rwxr-xr-xt/t4215-log-skewed-merges.sh147
2 files changed, 203 insertions, 7 deletions
diff --git a/graph.c b/graph.c
index e37127f..21edad8 100644
--- a/graph.c
+++ b/graph.c
@@ -217,6 +217,46 @@ struct git_graph {
*/
int merge_layout;
/*
+ * The number of columns added to the graph by the current commit. For
+ * 2-way and octopus merges, this is is usually one less than the
+ * number of parents:
+ *
+ * | | | | | \
+ * | * | | *---. \
+ * | |\ \ | |\ \ \ \
+ * | | | | | | | | | |
+ *
+ * num_parents: 2 num_parents: 4
+ * edges_added: 1 edges_added: 3
+ *
+ * For left-skewed merges, the first parent fuses with its neighbor and
+ * so one less column is added:
+ *
+ * | | | | | \
+ * | * | | *-. \
+ * |/| | |/|\ \ \
+ * | | | | | | | |
+ *
+ * num_parents: 2 num_parents: 4
+ * edges_added: 0 edges_added: 2
+ *
+ * This number determines how edges to the right of the merge are
+ * displayed in commit and post-merge lines; if no columns have been
+ * added then a vertical line should be used where a right-tracking
+ * line would otherwise be used.
+ *
+ * | * \ | * |
+ * | |\ \ |/| |
+ * | | * \ | * |
+ */
+ int edges_added;
+ /*
+ * The number of columns added by the previous commit, which is used to
+ * smooth edges appearing to the right of a commit in a commit line
+ * following a post-merge line.
+ */
+ int prev_edges_added;
+ /*
* The maximum number of columns that can be stored in the columns
* and new_columns arrays. This is also half the number of entries
* that can be stored in the mapping and new_mapping arrays.
@@ -328,6 +368,8 @@ struct git_graph *graph_init(struct rev_info *opt)
graph->commit_index = 0;
graph->prev_commit_index = 0;
graph->merge_layout = 0;
+ graph->edges_added = 0;
+ graph->prev_edges_added = 0;
graph->num_columns = 0;
graph->num_new_columns = 0;
graph->mapping_size = 0;
@@ -689,6 +731,9 @@ void graph_update(struct git_graph *graph, struct commit *commit)
*/
graph_update_columns(graph);
+ graph->prev_edges_added = graph->edges_added;
+ graph->edges_added = graph->num_parents + graph->merge_layout - 2;
+
graph->expansion_row = 0;
/*
@@ -947,12 +992,13 @@ static void graph_output_commit_line(struct git_graph *graph, struct graph_line
if (graph->num_parents > 2)
graph_draw_octopus_merge(graph, line);
- } else if (seen_this && (graph->num_parents > 2)) {
+ } else if (seen_this && (graph->edges_added > 1)) {
graph_line_write_column(line, col, '\\');
- } else if (seen_this && (graph->num_parents == 2)) {
+ } else if (seen_this && (graph->edges_added == 1)) {
/*
- * This is a 2-way merge commit.
- * There is no GRAPH_PRE_COMMIT stage for 2-way
+ * This is either a right-skewed 2-way merge
+ * commit, or a left-skewed 3-way merge.
+ * There is no GRAPH_PRE_COMMIT stage for such
* merges, so this is the first line of output
* for this commit. Check to see what the previous
* line of output was.
@@ -964,6 +1010,7 @@ static void graph_output_commit_line(struct git_graph *graph, struct graph_line
* makes the output look nicer.
*/
if (graph->prev_state == GRAPH_POST_MERGE &&
+ graph->prev_edges_added > 0 &&
graph->prev_commit_index < i)
graph_line_write_column(line, col, '\\');
else
@@ -1033,8 +1080,14 @@ static void graph_output_post_merge_line(struct git_graph *graph, struct graph_l
else
idx++;
}
+ if (graph->edges_added == 0)
+ graph_line_addch(line, ' ');
+
} else if (seen_this) {
- graph_line_write_column(line, col, '\\');
+ if (graph->edges_added > 0)
+ graph_line_write_column(line, col, '\\');
+ else
+ graph_line_write_column(line, col, '|');
graph_line_addch(line, ' ');
} else {
graph_line_write_column(line, col, '|');
diff --git a/t/t4215-log-skewed-merges.sh b/t/t4215-log-skewed-merges.sh
index dc187b5..e673cdb 100755
--- a/t/t4215-log-skewed-merges.sh
+++ b/t/t4215-log-skewed-merges.sh
@@ -11,7 +11,7 @@ test_expect_success 'log --graph with merge fusing with its left and right neigh
| * G
| |\
| | * F
- | * \ E
+ | * | E
|/|\ \
| | |/
| | * D
@@ -43,7 +43,7 @@ test_expect_success 'log --graph with left-skewed merge' '
| | | | * 0_G
| |_|_|/|
|/| | | |
- | | | * \ 0_F
+ | | | * | 0_F
| |_|/|\ \
|/| | | |/
| | | | * 0_E
@@ -73,4 +73,147 @@ test_expect_success 'log --graph with left-skewed merge' '
test_cmp expect actual
'
+test_expect_success 'log --graph with nested left-skewed merge' '
+ cat >expect <<-\EOF &&
+ * 1_H
+ |\
+ | * 1_G
+ | |\
+ | | * 1_F
+ | * | 1_E
+ |/| |
+ | * | 1_D
+ * | | 1_C
+ |/ /
+ * | 1_B
+ |/
+ * 1_A
+ EOF
+
+ git checkout --orphan 1_p &&
+ test_commit 1_A &&
+ test_commit 1_B &&
+ test_commit 1_C &&
+ git checkout -b 1_q @^ && test_commit 1_D &&
+ git checkout 1_p && git merge --no-ff 1_q -m 1_E &&
+ git checkout -b 1_r @~3 && test_commit 1_F &&
+ git checkout 1_p && git merge --no-ff 1_r -m 1_G &&
+ git checkout @^^ && git merge --no-ff 1_p -m 1_H &&
+
+ git log --graph --pretty=tformat:%s | sed "s/ *$//" >actual &&
+ test_cmp expect actual
+'
+
+test_expect_success 'log --graph with nested left-skewed merge following normal merge' '
+ cat >expect <<-\EOF &&
+ * 2_K
+ |\
+ | * 2_J
+ | |\
+ | | * 2_H
+ | | |\
+ | | * | 2_G
+ | |/| |
+ | | * | 2_F
+ | * | | 2_E
+ | |/ /
+ | * | 2_D
+ * | | 2_C
+ | |/
+ |/|
+ * | 2_B
+ |/
+ * 2_A
+ EOF
+
+ git checkout --orphan 2_p &&
+ test_commit 2_A &&
+ test_commit 2_B &&
+ test_commit 2_C &&
+ git checkout -b 2_q @^^ &&
+ test_commit 2_D &&
+ test_commit 2_E &&
+ git checkout -b 2_r @^ && test_commit 2_F &&
+ git checkout 2_q &&
+ git merge --no-ff 2_r -m 2_G &&
+ git merge --no-ff 2_p^ -m 2_H &&
+ git checkout -b 2_s @^^ && git merge --no-ff 2_q -m 2_J &&
+ git checkout 2_p && git merge --no-ff 2_s -m 2_K &&
+
+ git log --graph --pretty=tformat:%s | sed "s/ *$//" >actual &&
+ test_cmp expect actual
+'
+
+test_expect_success 'log --graph with nested right-skewed merge following left-skewed merge' '
+ cat >expect <<-\EOF &&
+ * 3_J
+ |\
+ | * 3_H
+ | |\
+ | | * 3_G
+ | * | 3_F
+ |/| |
+ | * | 3_E
+ | |\ \
+ | | |/
+ | | * 3_D
+ | * | 3_C
+ | |/
+ | * 3_B
+ |/
+ * 3_A
+ EOF
+
+ git checkout --orphan 3_p &&
+ test_commit 3_A &&
+ git checkout -b 3_q &&
+ test_commit 3_B &&
+ test_commit 3_C &&
+ git checkout -b 3_r @^ &&
+ test_commit 3_D &&
+ git checkout 3_q && git merge --no-ff 3_r -m 3_E &&
+ git checkout 3_p && git merge --no-ff 3_q -m 3_F &&
+ git checkout 3_r && test_commit 3_G &&
+ git checkout 3_p && git merge --no-ff 3_r -m 3_H &&
+ git checkout @^^ && git merge --no-ff 3_p -m 3_J &&
+
+ git log --graph --pretty=tformat:%s | sed "s/ *$//" >actual &&
+ test_cmp expect actual
+'
+
+test_expect_success 'log --graph with right-skewed merge following a left-skewed one' '
+ cat >expect <<-\EOF &&
+ * 4_H
+ |\
+ | * 4_G
+ | |\
+ | * | 4_F
+ |/| |
+ | * | 4_E
+ | |\ \
+ | | * | 4_D
+ | |/ /
+ |/| |
+ | | * 4_C
+ | |/
+ | * 4_B
+ |/
+ * 4_A
+ EOF
+
+ git checkout --orphan 4_p &&
+ test_commit 4_A &&
+ test_commit 4_B &&
+ test_commit 4_C &&
+ git checkout -b 4_q @^^ && test_commit 4_D &&
+ git checkout -b 4_r 4_p^ && git merge --no-ff 4_q -m 4_E &&
+ git checkout -b 4_s 4_p^^ &&
+ git merge --no-ff 4_r -m 4_F &&
+ git merge --no-ff 4_p -m 4_G &&
+ git checkout @^^ && git merge --no-ff 4_s -m 4_H &&
+
+ git log --graph --date-order --pretty=tformat:%s | sed "s/ *$//" >actual &&
+ test_cmp expect actual
+'
+
test_done