trailer: support values folded to multiple lines

Currently, interpret-trailers requires that a trailer be only on 1 line.
For example:

a: first line
   second line

would be interpreted as one trailer line followed by one non-trailer line.

Make interpret-trailers support RFC 822-style folding, treating those
lines as one logical trailer.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/Documentation/git-interpret-trailers.txt b/Documentation/git-interpret-trailers.txt
index 4966b5b..e99bda6 100644
--- a/Documentation/git-interpret-trailers.txt
+++ b/Documentation/git-interpret-trailers.txt
@@ -57,11 +57,12 @@ minus signs start the patch part of the message.
 
 When reading trailers, there can be whitespaces after the
 token, the separator and the value. There can also be whitespaces
-inside the token and the value.
+inside the token and the value. The value may be split over multiple lines with
+each subsequent line starting with whitespace, like the "folding" in RFC 822.
 
 Note that 'trailers' do not follow and are not intended to follow many
-rules for RFC 822 headers. For example they do not follow the line
-folding rules, the encoding rules and probably many other rules.
+rules for RFC 822 headers. For example they do not follow
+the encoding rules and probably many other rules.
 
 OPTIONS
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