The output from linkgit:git-format-patch[1] can lead to a different
commit message when applied with linkgit:git-am[1]. The patch that is
applied may also be different from the one that was generated, or patch
application may fail outright.
ifdef::git-am[]
See the <<discussion,DISCUSSION>> section above for the syntactic rules.
endif::git-am[]

ifndef::git-am[]
include::format-patch-end-of-commit-message.adoc[]
endif::git-am[]

Note that this is especially problematic for unindented diffs that occur
in the commit message; the diff in the commit message might get applied
along with the patch section, or the patch application machinery might
trip up because the patch target doesn't apply. This could for example
be caused by a diff in a Markdown code block.

The solution for this is to indent the diff or other text that could
cause problems.

This loss of fidelity might be simple to notice if you are applying
patches directly from a mailbox. However, changes originating from Git
could be applied in bulk, in which case this would be much harder to
notice. This could for example be a Linux distribution which uses patch
files to apply changes on top of the commits from the upstream
repositories. This goes to show that this behavior does not only impact
email workflows.

Given these limitations, one might be tempted to use a general-purpose
utility like patch(1) instead. However, patch(1) will not only look for
unindented diffs (like linkgit:git-am[1]) but will try to apply indented
diffs as well.