doc: commit-graph.adoc: fix up some formatting
The formatting markup syntax used in this document (markdown?) is not
interpreted correctly by asciidoc or asciidoctor. The main problem is
the use of a '## ' prefix markup for some sub-headings, along with the
use of '```' code markup and some missing literal blocks.
In order to improve the (html) document formatting:
- replace the '## ' prefix sub-title syntax with the '~~' underlining
syntax for the relevant sub-headings.
- replace the '```' code markup, which causes asciidoc(tor) to simply
remove the marked up text, with a literal block '----' markup.
- the second ascii diagram, in the 'Merging commit-graph files'
section, is not rendered correctly by asciidoctor (asciidoc is fine)
so enclose it in a '....' block.
Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/technical/commit-graph.adoc b/Documentation/technical/commit-graph.adoc
index 2c26e95..a259d15 100644
--- a/Documentation/technical/commit-graph.adoc
+++ b/Documentation/technical/commit-graph.adoc
@@ -39,6 +39,7 @@
Values 1-4 satisfy the requirements of parse_commit_gently().
There are two definitions of generation number:
+
1. Corrected committer dates (generation number v2)
2. Topological levels (generation number v1)
@@ -158,7 +159,8 @@
we enable fast writes of new commit data without rewriting the entire commit
history -- at least, most of the time.
-## File Layout
+File Layout
+~~~~~~~~~~~
A commit-graph chain uses multiple files, and we use a fixed naming convention
to organize these files. Each commit-graph file has a name
@@ -170,11 +172,11 @@
For example, if the `commit-graph-chain` file contains the lines
-```
+----
{hash0}
{hash1}
{hash2}
-```
+----
then the commit-graph chain looks like the following diagram:
@@ -213,7 +215,8 @@
`graph-{hash1}.graph` contains `{hash0}` while `graph-{hash2}.graph` contains
`{hash0}` and `{hash1}`.
-## Merging commit-graph files
+Merging commit-graph files
+~~~~~~~~~~~~~~~~~~~~~~~~~~
If we only added a new commit-graph file on every write, we would run into a
linear search problem through many commit-graph files. Instead, we use a merge
@@ -225,6 +228,7 @@
the commits in `graph-{hash1}` should be combined into a new `graph-{hash3}`
file.
+....
+---------------------+
| |
| (new commits) |
@@ -250,6 +254,7 @@
| |
| |
+-----------------------+
+....
During this process, the commits to write are combined, sorted and we write the
contents to a temporary file, all while holding a `commit-graph-chain.lock`
@@ -257,14 +262,15 @@
according to the computed `{hash3}`. Finally, we write the new chain data to
`commit-graph-chain.lock`:
-```
+----
{hash3}
{hash0}
-```
+----
We then close the lock-file.
-## Merge Strategy
+Merge Strategy
+~~~~~~~~~~~~~~
When writing a set of commits that do not exist in the commit-graph stack of
height N, we default to creating a new file at level N + 1. We then decide to
@@ -289,7 +295,8 @@
number of commits) could be extracted into config settings for full
flexibility.
-## Handling Mixed Generation Number Chains
+Handling Mixed Generation Number Chains
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
With the introduction of generation number v2 and generation data chunk, the
following scenario is possible:
@@ -318,7 +325,8 @@
rewriting split commit-graph as a single file (`--split=replace`) creates a
single layer with corrected commit dates.
-## Deleting graph-{hash} files
+Deleting graph-\{hash\} files
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
After a new tip file is written, some `graph-{hash}` files may no longer
be part of a chain. It is important to remove these files from disk, eventually.
@@ -333,7 +341,8 @@
defaults to zero, but can be changed using command-line arguments or a config
setting.
-## Chains across multiple object directories
+Chains across multiple object directories
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In a repo with alternates, we look for the `commit-graph-chain` file starting
in the local object directory and then in each alternate. The first file that
