Re: [PATCH 3/3] diff: make "too many files" rename warning optional

Jeff King [off-list ref] writes:

In many cases, the warning ends up as clutter, because the
diff is being done "behind the scenes" from the user (e.g.,
when generating a commit diffstat), and whether we show
renames or not is not particularly interesting to the user.

However, in the case of a merge (which is what motivated the
warning in the first place), it is a useful hint as to why a
merge with renames might have failed.

This patch makes the warning optional based on the code
calling into diffcore. We default to not showing the
warning, but turn it on for merges.

Signed-off-by: Jeff King <redacted>
---
This neglects the case where the user specifically does a diff asking
for renames, but we turn it off. Maybe when "-M" is specified on the
commandline to git-diff, we should set this option as well.

That sounds sensible.  Like this?

diff --git a/diff.c b/diff.c
index f735519..e8a9286 100644
--- a/diff.c
+++ b/diff.c

@@ -2443,6 +2443,7 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 		if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
 			return -1;
 		options->detect_rename = DIFF_DETECT_RENAME;
+		options->warn_on_too_large_rename = 1;
 	}
 	else if (!prefixcmp(arg, "-C")) {
 		if (options->detect_rename == DIFF_DETECT_COPY)

@@ -2450,6 +2451,7 @@ int diff_opt_parse(struct diff_options *options, const char **av, int ac)
 		if ((options->rename_score = diff_scoreopt_parse(arg)) == -1)
 			return -1;
 		options->detect_rename = DIFF_DETECT_COPY;
+		options->warn_on_too_large_rename = 1;
 	}
 	else if (!strcmp(arg, "--no-renames"))
 		options->detect_rename = 0;