blame: improve diagnosis for "--reverse NEW"

"git blame --reverse OLD..NEW -- PATH" tells us to start from the contents in PATH at OLD and observe how each line is changed while the history develops up to NEW, and report for each line the latest commit up to which the line survives in the original form. If you say "git blame --reverse NEW -- PATH" by mistake, we complain about the missing OLD, but we phrased it as "No commit to dig down to?" In this case, however, we are digging up from OLD, so say so. Signed-off-by: Junio C Hamano <gitster@pobox.com>

Junio C Hamano committed Jun 14, 2016 at 10:46 UTC d993ce1ed2f025708b0f78bed241466e35f1e8a0
2 files changed +3 -3
Documentation/git-blame.txt
+1 -1
@@ -10,7 +10,7 @@ SYNOPSIS
10 [verse]
11 'git blame' [-c] [-b] [-l] [--root] [-t] [-f] [-n] [-s] [-e] [-p] [-w] [--incremental]
12 [-L <range>] [-S <revs-file>] [-M] [-C] [-C] [-C] [--since=<date>]
13 - [--progress] [--abbrev=<n>] [<rev> | --contents <file> | --reverse <rev>]
13 + [--progress] [--abbrev=<n>] [<rev> | --contents <file> | --reverse <rev>..<rev>]
14 [--] <file>
15
16 DESCRIPTION
builtin/blame.c
+2 -2
@@ -2466,14 +2466,14 @@ static char *prepare_initial(struct scoreboard *sb)
2466 if (obj->type != OBJ_COMMIT)
2467 die("Non commit %s?", revs->pending.objects[i].name);
2468 if (sb->final)
2469 - die("More than one commit to dig down to %s and %s?",
2469 + die("More than one commit to dig up from, %s and %s?",
2470 revs->pending.objects[i].name,
2471 final_commit_name);
2472 sb->final = (struct commit *) obj;
2473 final_commit_name = revs->pending.objects[i].name;
2474 }
2475 if (!final_commit_name)
2476 - die("No commit to dig down to?");
2476 + die("No commit to dig up from?");
2477 return xstrdup(final_commit_name);
2478 }
2479