[PATCH v2 2/3] doc/fast-import: document feature import-marks-if-exists

[Dmitry Ivankov <divanorama@gmail.com>]

fast-import command-line option --import-marks-if-exists was introduced
in commit dded4f1 (fast-import: Introduce --import-marks-if-exists, 2011-01-15)

--import-marks option can be set via a "feature" command in a fast-import
stream and --import-marks-if-exists had support for such specification
from the very beginning too due to some shared codebase. Though the
documentation for this feature wasn't written in dded4f1.

Add the documentation for "feature import-marks-if-exists=<file>". Also add
a minimalistic test for it.

Signed-off-by: Dmitry Ivankov <divanorama@gmail.com>
---
Reworded a bit, united import-marks* descriptions. One more case to test:
--import-marks-if-exists= overrides feature import-marks=. And "fixed" the
test, I left the --import-marks accidentally, though it was a fine test too.
Also not feeling like adding a whole ton of coverage tests yet.

 Documentation/git-fast-import.txt |   10 +++++++---
 t/t9300-fast-import.sh            |   15 +++++++++++++++
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/Documentation/git-fast-import.txt b/Documentation/git-fast-import.txt
index 3f5b912..3a5aa55 100644
--- a/Documentation/git-fast-import.txt
+++ b/Documentation/git-fast-import.txt
@@ -1000,10 +1000,14 @@ force::
 	(see OPTIONS, above).
 
 import-marks::
+import-marks-if-exists::
 	Like --import-marks except in two respects: first, only one
-	"feature import-marks" command is allowed per stream;
-	second, an --import-marks= command-line option overrides
-	any "feature import-marks" command in the stream.
+	"feature import-marks" or "feature import-marks-if-exists"
+	command is allowed per stream; second, an --import-marks=
+	or --import-marks-if-exists command-line option overrides
+	any of these "feature" commands in the stream; third,
+	"feature import-marks-if-exists" like a corresponding
+	command-line option silently skips a nonexistent file.
 
 cat-blob::
 ls::
diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index 2a53640..9af1a78 100755
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -1882,6 +1882,21 @@ test_expect_success 'R: --import-marks-if-exists' '
 	test_cmp expect io.marks
 '
 
+test_expect_success 'R: feature import-marks-if-exists' '
+	rm -f io.marks &&
+	blob=$(echo hi | git hash-object --stdin) &&
+	echo ":1 $blob" >expect &&
+	git fast-import --export-marks=io.marks <<-\EOF &&
+	feature import-marks-if-exists=io.marks
+	blob
+	mark :1
+	data 3
+	hi
+
+	EOF
+	test_cmp expect io.marks
+'
+
 cat >input << EOF
 feature import-marks=marks.out
 feature export-marks=marks.new
-- 
1.7.3.4