git/graph.c, branch v2.25.2

graph: fix lack of color in horizontal lines

2020-01-08T17:37:18Z

In some cases, horizontal lines in rendered graphs can lose their coloring. This is due to a use of graph_line_addch() instead of graph_line_write_column(). Using a ternary operator to pick the character is nice for compact code, but we actually need a column to provide the color. Add a test to t4215-log-skewed-merges.sh to prevent regression. Reported-by: Jeff King Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano

graph: drop assert() for merge with two collapsing parents

2020-01-08T17:35:07Z

When "git log --graph" shows a merge commit that has two collapsing lines, like: | | | | * | |_|_|/| |/| | |/ | | |/| | |/| | | * | | * | | | we trigger an assert(): graph.c:1228: graph_output_collapsing_line: Assertion `graph->mapping[i - 3] == target' failed. The assert was introduced by eaf158f8 ("graph API: Use horizontal lines for more compact graphs", 2009-04-21), which is quite old. This assert is trying to say that when we complete a horizontal line with a single slash, it is because we have reached our target. It is actually the _second_ collapsing line that hits this assert. The reason we are in this code path is because we are collapsing the first line, and in that case we are hitting our target now that the horizontal line is complete. However, the second line cannot be a horizontal line, so it will collapse without horizontal lines. In this case, it is inappropriate to assert that we have reached our target, as we need to continue for another column before reaching the target. Dropping the assert is safe here. The new behavior in 0f0f389f12 (graph: tidy up display of left-skewed merges, 2019-10-15) caused the behavior change that made this assertion failure possible. In addition to making the assert possible, it also changed how multiple edges collapse. In a larger example, the current code will output a collapse as follows: | | | | | | * | |_|_|_|_|/|\ |/| | | | |/ / | | | | |/| / | | | |/| |/ | | |/| |/| | |/| |/| | | | |/| | | | | * | | | However, the intended collapse should allow multiple horizontal lines as follows: | | | | | | * | |_|_|_|_|/|\ |/| | | | |/ / | | |_|_|/| / | |/| | | |/ | | | |_|/| | | |/| | | | | * | | | This behavior is not corrected by this change, but is noted for a later update. Helped-by: Jeff King Reported-by: Bradley Smith Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano

Merge branch 'hw/doc-in-header'

2019-12-16T21:08:39Z

* hw/doc-in-header: trace2: move doc to trace2.h submodule-config: move doc to submodule-config.h tree-walk: move doc to tree-walk.h trace: move doc to trace.h run-command: move doc to run-command.h parse-options: add link to doc file in parse-options.h credential: move doc to credential.h argv-array: move doc to argv-array.h cache: move doc to cache.h sigchain: move doc to sigchain.h pathspec: move doc to pathspec.h revision: move doc to revision.h attr: move doc to attr.h refs: move doc to refs.h remote: move doc to remote.h and refspec.h sha1-array: move doc to sha1-array.h merge: move doc to ll-merge.h graph: move doc to graph.h and graph.c dir: move doc to dir.h diff: move doc to diff.h and diffcore.h

fix-typo: consecutive-word duplications

2019-12-16T19:53:11Z

Correct unintentional duplication(s) of words, such as "the the", and "can can" etc. The changes are only applied to cases where it's fixing what is clearly wrong or prone to misunderstanding, as suggested by the reviewers. Helped-by: Johannes Schindelin Helped-by: Denton Liu Helped-by: Junio C Hamano Signed-off-by: ryenus Signed-off-by: Junio C Hamano

graph: move doc to graph.h and graph.c

2019-11-18T06:21:28Z

Move the documentation from Documentation/technical/api-history-graph.txt to graph.h and graph.c as it's easier for the developers to find the usage information beside the code instead of looking for it in another doc file. The graph library was already well documented, so few comments were added to both graph.h and graph.c Also documentation/technical/api-history-graph.txt is removed because the information it has is now redundant and it'll be hard to keep it up to date and synchronized with the documentation in the header file. Signed-off-by: Heba Waly Signed-off-by: Junio C Hamano

graph: fix coloring of octopus dashes

2019-10-16T02:11:25Z

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 Signed-off-by: Junio C Hamano

graph: flatten edges that fuse with their right neighbor

2019-10-16T02:11:25Z

When a merge commit is printed and its final parent is the same commit that occupies the column to the right of the merge, this results in a kink in the displayed edges: * | |\ \ | |/ | * Graphs containing these shapes can be hard to read, as the expansion to the right followed immediately by collapsing back to the left creates a lot of zig-zagging edges, especially when many columns are present. We can improve this by eliminating the zig-zag and having the merge's final parent edge fuse immediately with its neighbor: * | |\| | * This reduces the horizontal width for the current commit by 2, and requires one less row, making the graph display more compact. Taken in combination with other graph-smoothing enhancements, it greatly compresses the space needed to display certain histories: * |\ | * * | |\ |\ | | * | * | | | | |\ | | \ | | * | *-. \ | * | | |\ \ \ => |/|\| |/ / / / | | * | | | / | * | | | |/ | |/ | | * * / | * | |/ | |/ * * | |/ * One of the test cases here cannot be correctly rendered in Git v2.23.0; it produces this output following commit E: | | *-. \ 5_E | | |\ \ \ | |/ / / / | | | / _ | |_|/ |/| | The new implementation makes sure that the rightmost edge in this history is not left dangling as above. Signed-off-by: James Coglan Signed-off-by: Junio C Hamano

graph: smooth appearance of collapsing edges on commit lines

2019-10-16T02:11:25Z

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 Signed-off-by: Junio C Hamano

graph: rename `new_mapping` to `old_mapping`

2019-10-16T02:11:25Z

The change I'm about to make requires being able to inspect the mapping array that was used to render the last GRAPH_COLLAPSING line while rendering a GRAPH_COMMIT line. The `new_mapping` array currently exists as a pre-allocated space for computing the next `mapping` array during `graph_output_collapsing_line()`, but we can repurpose it to let us see the previous `mapping` state. To support this use it will make more sense if this array is named `old_mapping`, as it will contain the mapping data for the previous line we rendered, at the point we're rendering a commit line. Signed-off-by: James Coglan Signed-off-by: Junio C Hamano

graph: commit and post-merge lines for left-skewed merges

2019-10-16T02:11:25Z

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 Signed-off-by: Junio C Hamano