line-log: allow non-patch diff formats with -L

Now that -L flows through log_tree_diff_flush() and diff_flush(),
metadata-only diff formats work because they only read filepair
fields (status, mode, path, oid) already set on the pre-computed
pairs.

Expand the allowlist in setup_revisions() to also accept --raw,
--name-only, --name-status, --summary, and --check.  Diff stat
formats (--stat, --numstat, --shortstat, --dirstat) remain blocked
because they call compute_diffstat() on full blob content and would
show whole-file statistics rather than range-scoped ones.

Also reject --full-diff, which is meaningless with -L: the filepairs
are pre-computed during the history walk and scoped to tracked paths,
so there is no tree diff to widen.

Signed-off-by: Michael Montalbo <mmontalbo@gmail.com>

Author: mmontalbo

Documentation/line-range-options.adoc

@@ -8,9 +8,11 @@
 	give zero or one positive revision arguments, and
 	_<start>_ and _<end>_ (or _<funcname>_) must exist in the starting revision.
 	You can specify this option more than once. Implies `--patch`.
-	Patch output can be suppressed using `--no-patch`, but other diff formats
-	(namely `--raw`, `--numstat`, `--shortstat`, `--dirstat`, `--summary`,
-	`--name-only`, `--name-status`, `--check`) are not currently implemented.
+	Patch output can be suppressed using `--no-patch`.
+	Non-patch diff formats `--raw`, `--name-only`, `--name-status`,
+	`--summary`, and `--check` are supported; diff stat formats
+	(`--stat`, `--numstat`, `--shortstat`, `--dirstat`) are not
+	currently implemented.
 +
 Patch formatting options such as `--word-diff`, `--color-moved`,
 `--no-prefix`, and whitespace options (`-w`, `-b`) are supported,

revision.c

@@ -3179,8 +3179,15 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, struct s
 		die(_("the option '%s' requires '%s'"), "--grep-reflog", "--walk-reflogs");
 
 	if (revs->line_level_traverse &&
-	    (revs->diffopt.output_format & ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT)))
-		die(_("-L does not yet support diff formats besides -p and -s"));
+	    (revs->diffopt.output_format &
+	     ~(DIFF_FORMAT_PATCH | DIFF_FORMAT_NO_OUTPUT |
+	       DIFF_FORMAT_RAW | DIFF_FORMAT_NAME |
+	       DIFF_FORMAT_NAME_STATUS | DIFF_FORMAT_SUMMARY |
+	       DIFF_FORMAT_CHECKDIFF)))
+		die(_("-L does not yet support diff stat formats "
+		      "(--stat, --numstat, --shortstat, --dirstat)"));
+	if (revs->line_level_traverse && revs->full_diff)
+		die(_("-L is not compatible with --full-diff"));
 
 	if (revs->expand_tabs_in_log < 0)
 		revs->expand_tabs_in_log = revs->expand_tabs_in_log_default;

t/t4211-line-log.sh

@@ -155,8 +155,35 @@ test_expect_success '-p shows the default patch output' '
 	test_cmp expect actual
 '
 
-test_expect_success '--raw is forbidden' '
-	test_must_fail git log -L1,24:b.c --raw
+test_expect_success '--raw shows mode, oid, status and path' '
+	git log -L1,24:b.c --raw --format= >actual &&
+	grep "^:100644 100644 [0-9a-f]\{7\} [0-9a-f]\{7\} M	b.c$" actual &&
+	! grep "^diff --git" actual &&
+	! grep "^@@" actual
+'
+
+test_expect_success '--name-only shows path' '
+	git log -L1,24:b.c --name-only --format= >actual &&
+	grep "^b.c$" actual &&
+	! grep "^diff --git" actual &&
+	! grep "^@@" actual
+'
+
+test_expect_success '--name-status shows status and path' '
+	git log -L1,24:b.c --name-status --format= >actual &&
+	grep "^M	b.c$" actual &&
+	! grep "^diff --git" actual &&
+	! grep "^@@" actual
+'
+
+test_expect_success '--stat is not yet supported with -L' '
+	test_must_fail git log -L1,24:b.c --stat 2>err &&
+	test_grep "does not yet support" err
+'
+
+test_expect_success '--full-diff is not supported with -L' '
+	test_must_fail git log -L1,24:b.c --full-diff 2>err &&
+	test_grep "not compatible with --full-diff" err
 '
 
 test_expect_success 'setup for checking fancy rename following' '
@@ -725,4 +752,49 @@ test_expect_success '-L with -S suppresses non-matching commits' '
 	test_cmp expect actual
 '
 
+test_expect_success '--summary shows new file on root commit' '
+	git checkout parent-oids &&
+	git log -L:func2:file.c --summary --format= >actual &&
+	grep "create mode 100644 file.c" actual
+'
+
+test_expect_success 'setup for --check test' '
+	git checkout --orphan check-test &&
+	git reset --hard &&
+	cat >check.c <<-\EOF &&
+	void tracked()
+	{
+	    return;
+	}
+
+	void other()
+	{
+	    return;
+	}
+	EOF
+	git add check.c &&
+	test_tick &&
+	git commit -m "add check.c" &&
+	# Introduce trailing whitespace errors in both functions
+	sed "s/return;/return; /" check.c >check.c.tmp &&
+	mv check.c.tmp check.c &&
+	git commit -a -m "introduce trailing whitespace"
+'
+
+test_expect_success '--check reports whitespace errors in tracked range' '
+	test_must_fail git log -L:tracked:check.c --check --format= >actual &&
+	grep "trailing whitespace" actual
+'
+
+# --check currently examines the entire file diff, not just the tracked
+# range.  Scoping --check to line_ranges would require threading range
+# filtering into run_checkdiff(), similar to how builtin_diff() filters
+# patch output.
+test_expect_failure '--check should not report errors outside tracked range' '
+	test_must_fail git log -L:tracked:check.c --check --format= >actual &&
+	# line 3 is inside tracked(), line 8 is inside other()
+	grep "check.c:3" actual &&
+	! grep "check.c:8" actual
+'
+
 test_done