[Libguestfs] [libnbd PATCH] maint: Suggest better diff output for API.ml

[Eric Blake]

Git diff is able to customize the regex used to locate "function
headers", or the text to output on @@ lines of a patch to make it
easier to determine which portion of a file the patch touches.  This
is done by coupling .gitattributes contents with the user running the
right 'git config' command.  We don't have a bootstrap script, so we
don't have an automated place to forcefully ensure the right setup for
new contributors, but we can at least document the steps a developer
can do to make our lives easier.

For the API.ml file, not only do we want to highlight typical
top-level OCaml 'let' statements, we also want to highlight the start
of each of our API definitions.

Thanks: Laszlo Ersek <lersek at redhat.com>
---
 .gitattributes | 3 +++
 README         | 4 ++++
 2 files changed, 7 insertions(+)
 create mode 100644 .gitattributes

diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 00000000..cf630ae9
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,3 @@
+# Use the following one-time config to get nicer API diffs:
+#    git config diff.api.xfuncname '^(let .*=|  "[^"]*", \{$)'
+API.ml diff=api
diff --git a/README b/README
index 6502e7fc..8955f817 100644
--- a/README
+++ b/README
@@ -168,6 +168,10 @@ When testing use:
     make check
     make check-valgrind

+Use the following one-time setup for nicer diffs:
+
+    git config diff.api.xfuncname '^(let .*=|  "[^"]*", \{$)'
+
 For development ideas, see the TODO file.

 The upstream git repository is:
-- 
2.33.1