In 04005834ed ("log: fix coloring of certain octopus merge shapes",
2018-09-01) there is a fix for the coloring of dashes following an
octopus merge. It makes a distinction between the case where all parents
introduce a new column, versus the case where the first parent collapses
into an existing column:
| *-. | *-.
| |\ \ | |\ \
| | | | |/ / /
The latter case means that the columns for the merge parents begin one
place to the left in the `new_columns` array compared to the former
case.
However, the implementation only works if the commit's parents are kept
in order as they map onto the visual columns, as we get the colors by
iterating over `new_columns` as we print the dashes. In general, the
commit's parents can arbitrarily merge with existing columns, and change
their ordering in the process.
For example, in the following diagram, the number of each column
indicates which commit parent appears in each column.
| | *---.
| | |\ \ \
| | |/ / /
| |/| | /
| |_|_|/
|/| | |
3 1 0 2
If the columns are colored (red, green, yellow, blue), then the dashes
will currently be colored yellow and blue, whereas they should be blue
and red.
To fix this, we need to look up each column in the `mapping` array,
which before the `GRAPH_COLLAPSING` state indicates which logical column
is displayed in each visual column. This implementation is simpler as it
doesn't have any edge cases, and it also handles how left-skewed first
parents are now displayed:
| *-.
|/|\ \
| | | |
0 1 2 3
The color of the first dashes is always the color found in `mapping` two
columns to the right of the commit symbol. Because commits are displayed
after all edges have been collapsed together and the visual columns
match the logical ones, we can find the visual offset of the commit
symbol using `commit_index`.
Signed-off-by: James Coglan <jcoglan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When a graph contains edges that are in the process of collapsing to the
left, but those edges cross a commit line, the effect is that the edges
have a jagged appearance:
*
|\
| *
| \
*-. \
|\ \ \
| | * |
| * | |
| |/ /
* | |
|/ /
* |
|/
*
We already takes steps to smooth edges like this when they're expanding;
when an edge appears to the right of a merge commit marker on a
GRAPH_COMMIT line immediately following a GRAPH_POST_MERGE line, we
render it as a `\`:
* \
|\ \
| * \
| |\ \
We can make a similar improvement to collapsing edges, making them
easier to follow and giving the overall graph a feeling of increased
symmetry:
*
|\
| *
| \
*-. \
|\ \ \
| | * |
| * | |
| |/ /
* / /
|/ /
* /
|/
*
To do this, we introduce a new special case for edges on GRAPH_COMMIT
lines that immediately follow a GRAPH_COLLAPSING line. By retaining a
copy of the `mapping` array used to render the GRAPH_COLLAPSING line in
the `old_mapping` array, we can determine that an edge is collapsing
through the GRAPH_COMMIT line and should be smoothed.
Signed-off-by: James Coglan <jcoglan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.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 vertical 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 <jcoglan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The graph coloring logic for octopus merges currently has a bug. This
can be seen git.git with 74c7cfa875 (Merge of
http://members.cox.net/junkio/git-jc.git, 2005-05-05), whose second
child is 211232bae6 (Octopus merge of the following five patches.,
2005-05-05).
If one runs
git log --graph 74c7cfa875
one can see that the octopus merge is colored incorrectly. In
particular, the horizontal dashes are off by one color. Each horizontal
dash should be the color of the line to their bottom-right. Instead, they
are currently the color of the line to their bottom.
Demonstrate this breakage with a few sets of test cases. These test
cases should show not only simple cases of the bug occuring but trickier
situations that may not be handled properly in any attempt to fix the
bug.
While we're at it, include a passing test case as a canary in case an
attempt to fix the bug breaks existing operation.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In a future test case, we will be extending the commit graph. As a
result, explicitly list the tags that will generate the graph so that
when future additions are made, the current graph illustrations won't be
affected.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Before, the expect files of the test case were being generated in the
setup method. However, it would make more sense to generate these files
within the test cases that actually use them so that it's obvious to
future readers where the expected values are coming from.
Move the generation of the expect files in their own respective test
cases.
While we're at it, we want to establish a pattern in this test suite
that, firstly, a non-colored test case is given then, immediately after,
the colored version is given.
Switch test cases "log --graph with tricky octopus merge, no color" and
"log --graph with tricky octopus merge with colors" so that the "no
color" version appears first.
This patch is best viewed with `--color-moved`.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
In the previous commit, we extended test_merge() so that it could
perform octopus merges. Now that the restriction is lifted, use
test_merge() to perform the octopus merge instead of manually
duplicating test_merge() functionality.
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
For octopus merges where the first parent edge immediately merges into
the next column to the left, the number of columns should be one less
than the usual case.
First parent to the left case:
| *-.
| |\ \
|/ / /
The usual case:
| *-.
| |\ \
| | | *
Also refactor the code to iterate over columns rather than dashes,
building from an initial patch suggested by Jeff King.
Signed-off-by: Noam Postavsky <npostavs@users.sourceforge.net>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
