Merge branch 'tr/maint-show-walk' into maint

"git show"'s auto-walking behaviour was an unreliable and
unpredictable hack; it now behaves just like "git log" does when it
walks.

* tr/maint-show-walk:
  show: fix "range implies walking"
  Demonstrate git-show is broken with ranges

builtin/log.c

@@ -462,6 +462,9 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 	opt.tweak = show_rev_tweak_rev;
 	cmd_log_init(argc, argv, prefix, &rev, &opt);
 
+	if (!rev.no_walk)
+		return cmd_log_walk(&rev);
+
 	count = rev.pending.nr;
 	objects = rev.pending.objects;
 	for (i = 0; i < count && !ret; i++) {

t/t7007-show.sh

@@ -17,4 +17,95 @@ test_expect_success 'showing a tag that point at a missing object' '
 	test_must_fail git --no-pager show foo-tag
 '
 
+test_expect_success 'set up a bit of history' '
+	test_commit main1 &&
+	test_commit main2 &&
+	test_commit main3 &&
+	git tag -m "annotated tag" annotated &&
+	git checkout -b side HEAD^^ &&
+	test_commit side2 &&
+	test_commit side3
+'
+
+test_expect_success 'showing two commits' '
+	cat >expect <<-EOF &&
+	commit $(git rev-parse main2)
+	commit $(git rev-parse main3)
+	EOF
+	git show main2 main3 >actual &&
+	grep ^commit actual >actual.filtered &&
+	test_cmp expect actual.filtered
+'
+
+test_expect_success 'showing a range walks (linear)' '
+	cat >expect <<-EOF &&
+	commit $(git rev-parse main3)
+	commit $(git rev-parse main2)
+	EOF
+	git show main1..main3 >actual &&
+	grep ^commit actual >actual.filtered &&
+	test_cmp expect actual.filtered
+'
+
+test_expect_success 'showing a range walks (Y shape, ^ first)' '
+	cat >expect <<-EOF &&
+	commit $(git rev-parse main3)
+	commit $(git rev-parse main2)
+	EOF
+	git show ^side3 main3 >actual &&
+	grep ^commit actual >actual.filtered &&
+	test_cmp expect actual.filtered
+'
+
+test_expect_success 'showing a range walks (Y shape, ^ last)' '
+	cat >expect <<-EOF &&
+	commit $(git rev-parse main3)
+	commit $(git rev-parse main2)
+	EOF
+	git show main3 ^side3 >actual &&
+	grep ^commit actual >actual.filtered &&
+	test_cmp expect actual.filtered
+'
+
+test_expect_success 'showing with -N walks' '
+	cat >expect <<-EOF &&
+	commit $(git rev-parse main3)
+	commit $(git rev-parse main2)
+	EOF
+	git show -2 main3 >actual &&
+	grep ^commit actual >actual.filtered &&
+	test_cmp expect actual.filtered
+'
+
+test_expect_success 'showing annotated tag' '
+	cat >expect <<-EOF &&
+	tag annotated
+	commit $(git rev-parse annotated^{commit})
+	EOF
+	git show annotated >actual &&
+	grep -E "^(commit|tag)" actual >actual.filtered &&
+	test_cmp expect actual.filtered
+'
+
+test_expect_success 'showing annotated tag plus commit' '
+	cat >expect <<-EOF &&
+	tag annotated
+	commit $(git rev-parse annotated^{commit})
+	commit $(git rev-parse side3)
+	EOF
+	git show annotated side3 >actual &&
+	grep -E "^(commit|tag)" actual >actual.filtered &&
+	test_cmp expect actual.filtered
+'
+
+test_expect_success 'showing range' '
+	cat >expect <<-EOF &&
+	commit $(git rev-parse main3)
+	commit $(git rev-parse main2)
+	EOF
+	git show ^side3 annotated >actual &&
+	grep -E "^(commit|tag)" actual >actual.filtered &&
+	test_cmp expect actual.filtered
+'
+
 test_done