Re: [PATCH v2 1/8] make_transient_cache_entry(): optionally alloc from mem_pool

 struct cache_entry *make_transient_cache_entry(unsigned int mode,
                                               const struct object_id *oid,
                                               const char *path,
-                                              int stage);
+                                              int stage, struct mem_pool *mp);

It's a bit strange that `int stage` isn't on its own line here, as
other parameters are. And if line length was the issue, it looks like
it could have been on the same line as `const char *path`.

-struct cache_entry *make_transient_cache_entry(unsigned int mode, const struct object_id *oid,
-                                              const char *path, int stage)
+struct cache_entry *make_transient_cache_entry(unsigned int mode,
+                                              const struct object_id *oid,
+                                              const char *path, int stage,

Here also, it's a bit strange that `int stage` isn't on its own line,
as it looks like you want  to put others parameters on their own line.
And this is not consistent with the above declaration.

+                                              struct mem_pool *mp)