[PATCH] pretty.c: Don't expand %N without --show-notes

[Johannes Gilger <heipei@hackvalue.de>]

The %N placeholder will only work if --show-notes was provided to log.
By not expanding the user is given feedback that he won't be shown any
notes.

Signed-off-by: Johannes Gilger <heipei@hackvalue.de>
---
 Ok, this is another stab. I don't really know whether we want %N to expand to
 an empty string or not expand at all in case of no --show-notes. Obviously
 using 'return 1;' would implement the former behaviour, while I chose the
 latter because it prevents people like me from building useless log aliases.

 Documentation/pretty-formats.txt |    3 ++-
 pretty.c                         |    3 +++
 2 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/Documentation/pretty-formats.txt b/Documentation/pretty-formats.txt
index 1686a54..bf7813f 100644
--- a/Documentation/pretty-formats.txt
+++ b/Documentation/pretty-formats.txt
@@ -143,7 +143,8 @@ NOTE: Some placeholders may depend on other options given to the
 revision traversal engine. For example, the `%g*` reflog options will
 insert an empty string unless we are traversing reflog entries (e.g., by
 `git log -g`). The `%d` placeholder will use the "short" decoration
-format if `--decorate` was not already provided on the command line.
+format if `--decorate` was not already provided on the command line. The %N
+placeholder won't be expanded unless `--show-notes` was provided.
 
 If you add a `{plus}` (plus sign) after '%' of a placeholder, a line-feed
 is inserted immediately before the expansion if and only if the
diff --git a/pretty.c b/pretty.c
index 6ba3da8..b39e2d5 100644
--- a/pretty.c
+++ b/pretty.c
@@ -775,6 +775,9 @@ static size_t format_commit_one(struct strbuf *sb, const char *placeholder,
 		}
 		return 0;	/* unknown %g placeholder */
 	case 'N':
+		if (!c->pretty_ctx->show_notes)
+			return 0;
+
 		format_display_notes(commit->object.sha1, sb,
 			    git_log_output_encoding ? git_log_output_encoding
 						    : git_commit_encoding, 0);
-- 
1.7.0.2.201.g80978