On Wed, Jun 27, 2018 at 3:24 PM, Derrick Stolee [off-list ref] wrote:

When writing commit-graph files, it can be convenient to ask for all
reachable commits (starting at the ref set) in the resulting file. This
is particularly helpful when writing to stdin is complicated, such as a
future integration with 'git gc'.

It would be nice if the "Future Work" section of
Documentation/technical/commit-graph.txt had something about
integration with 'git gc'.

 With the `--stdin-commits` option, generate the new commit graph by
 walking commits starting at the commits specified in stdin as a list
 of OIDs in hex, one OID per line. (Cannot be combined with
---stdin-packs.)
+`--stdin-packs` or `--reachable`.)
++
+With the `--reachable` option, generate the new commit graph by walking
+commits starting at all refs. (Cannot be combined with `--stdin-commits`
+or `--stdin-packs`.)
 +
 With the `--append` option, include all commits that are present in the
 existing commit-graph file.

The "EXAMPLES" section still contains:

* Write a graph file containing all reachable commits.
+
------------------------------------------------
$ git show-ref -s | git commit-graph write --stdin-commits
------------------------------------------------

I wonder if this should have been changed to use `--reachable`.

Thanks!