44451a2e5e (attr: teach "--attr-source=" global option to "git", 2023-05-06)
provided the ability to pass in a treeish as the attr source. When a
revision does not resolve to a valid tree is passed, Git will die. At
GitLab, we server repositories as bare repos and would like to always read
attributes from the default branch, so we'd like to pass in HEAD as the
treeish to read gitattributes from on every command. In this context we
would not want Git to die if HEAD is unborn, like in the case of empty
repositories.

Instead of modifying the default behavior of --attr-source, create a pair of
configs attr.tree and attr.allowInvalidSource whereby an admin can configure
a ref for all commands to read gitattributes from, and another config that
relaxes the requirement that this treeish resolve to a valid tree.

Changes since v1:

 * Added a commit to add attr.tree config

John Cai (2):
  attr: add attr.tree for setting the treeish to read attributes from
  attr: add attr.allowInvalidSource config to allow invalid revision

 Documentation/config.txt      |  2 ++
 Documentation/config/attr.txt | 12 +++++++++
 attr.c                        | 21 +++++++++++++--
 t/t0003-attributes.sh         | 49 +++++++++++++++++++++++++++++++++++
 4 files changed, 82 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/config/attr.txt

base-commit: 1fc548b2d6a3596f3e1c1f8b1930d8dbd1e30bf3

Submitted-As: https://lore.kernel.org/git/pull.1577.v2.git.git.1696443502.gitgitgadget@gmail.com
In-Reply-To: https://lore.kernel.org/git/pull.1577.git.git.1695218431033.gitgitgadget@gmail.com