Restore depfile toleration of multiple output paths on distinct lines

Prior to introduction of depfile parser handling of multiple rules,
ninja silently accepted a depfile of the form:

    out: in1 in2 in3
    other: otherIn1 otherIn2 otherIn3

and incorrectly treated `other` and `otherIn*` as additional inputs to
`out`.  Now we prefer to reject this just as we already do for a depfile
specifying multiple outputs on one line.  However, this can break
existing cases where such a depfile was silently tolerated.

Add a `-w depfilemulti={err,warn}` option to control this behavior,
and make it just a warning by default.

1 files changed, 10 insertions, 3 deletions

diff --git a/src/depfile_parser_test.cc b/src/depfile_parser_test.cc
index 70e4029..52fe7cd 100644
--- a/src/depfile_parser_test.cc
+++ b/src/depfile_parser_test.cc
@@ -276,8 +276,15 @@ TEST_F(DepfileParserTest, MultipleRulesTolerateMP) {
 TEST_F(DepfileParserTest, MultipleRulesRejectDifferentOutputs) {
   // check that multiple different outputs are rejected by the parser
   // when spread across multiple rules
+  DepfileParserOptions parser_opts;
+  parser_opts.depfile_distinct_target_lines_action_ =
+      kDepfileDistinctTargetLinesActionError;
+  DepfileParser parser(parser_opts);
   string err;
-  EXPECT_FALSE(Parse("foo: x y\n"
-                     "bar: y z\n", &err));
-  ASSERT_EQ("depfile has multiple output paths", err);
+  string input =
+      "foo: x y\n"
+      "bar: y z\n";
+  EXPECT_FALSE(parser.Parse(&input, &err));
+  ASSERT_EQ("depfile has multiple output paths (on separate lines)"
+            " [-w depfilemulti=err]", err);
 }