Teach fast-import to ignore lines starting with '#'

Several frontend developers have asked that some form of stream
comments be permitted within a fast-import data stream.  This way
they can include information from their own frontend program about
where specific data was taken from in the source system, or about
a decision that their frontend may have made while creating the
fast-import data stream.

This change introduces comments in the Bourne-shell/Tcl/Perl style.
Lines starting with '#' are ignored, up to and including the LF.
Unlike the above mentioned three languages however we do not look for
and ignore leading whitespace.  This just simplifies the definition
of the comment format and the code that parses them.

To make comments work we had to stop using read_next_command() within
cmd_data() and directly invoke read_line() during the inline variant
of the function.  This is necessary to retain any lines of the
input data that might otherwise look like a comment to fast-import.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

1 files changed, 40 insertions, 0 deletions

diff --git a/t/t9300-fast-import.sh b/t/t9300-fast-import.sh
index dac6135b2..1f6426a49 100755
--- a/t/t9300-fast-import.sh
+++ b/t/t9300-fast-import.sh
@@ -778,4 +778,44 @@ test_expect_success \
 	'git-fast-import <input &&
 	 test `git-rev-parse N2^{tree}` = `git-rev-parse N3^{tree}`'
 
+###
+### series O
+###
+
+cat >input <<INPUT_END
+#we will
+commit refs/heads/O1
+# -- ignore all of this text
+committer $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> $GIT_COMMITTER_DATE
+# $GIT_COMMITTER_NAME has inserted here for his benefit.
+data <<COMMIT
+dirty directory copy
+COMMIT
+
+# don't forget the import blank line!
+#
+# yes, we started from our usual base of branch^0.
+# i like branch^0.
+from refs/heads/branch^0
+# and we need to reuse file2/file5 from N3 above.
+M 644 inline file2/file5
+# otherwise the tree will be different
+data <<EOF
+$file5_data
+EOF
+
+# don't forget to copy file2 to file3
+C file2 file3
+#
+# or to delete file5 from file2.
+D file2/file5
+# are we done yet?
+
+INPUT_END
+
+test_expect_success \
+	'O: comments are all skipped' \
+	'git-fast-import <input &&
+	 test `git-rev-parse N3` = `git-rev-parse O1`'
+
 test_done