[bug#50363] [PATCH v2] Improve default diff hunk header detection.

[Sarah Morgensen <iskarian@mgsn.dev>]

Tell git to look for top-level definitions for diff hunk headers in
Scheme files.

.gitattributes: New file.
.gitconfig: New file.
---
Hello Guix,

This patch improves the diff hunk headers for diffs on scheme files in this
repository.  These settings are always settable (and overridable) on a
per-user basis, but I think having them as defaults is nice.

This may help with patches applying in general, but the main goal is to make
etc/committer.scm a little less brittle.

The default "scheme" function regex (enabled with .gitattributes) recognizes
both toplevel and non-toplevel defines.  I've modified the regex in .gitconfig
to only recognize the toplevel defines.  I think this makes more sense for our
purposes.

Unfortunately, checked-in git config settings cannot be automatically used
(for security reasons), and must be enabled with a once-per-clone

  git config --local include.path ../.gitconfig

which isn't ideal.  I suppose we could make a 'make' target for setup like
this if we wanted to make it easy.

WDYT?

--
Sarah

 .gitattributes | 2 ++
 .gitconfig     | 2 ++
 2 files changed, 4 insertions(+)
 create mode 100644 .gitattributes
 create mode 100644 .gitconfig

diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000000..5c1b15e9e0
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,2 @@
+*.scm       diff=scheme
+*.scm.in    diff=scheme
diff --git a/.gitconfig b/.gitconfig
new file mode 100644
index 0000000000..344d829824
--- /dev/null
+++ b/.gitconfig
@@ -0,0 +1,2 @@
+[diff "scheme"]
+	xfuncname = "^(\\(define.*)$"

base-commit: 522a3bf99cbc21a9093f63280b9508cd69b94ff0
-- 
2.31.1