feat(mkdwarfs): exit with code 2 in case of recoverable errors

doc/mkdwarfs.md

@@ -419,6 +419,13 @@ Most other options are concerned with compression tuning:
   Show full usage with all options, including defaults, compression level
   detail and supported compression algorithms.
 
+## EXIT CODES
+
+Upon successful completion, `mkdwarfs` will exit with exit code 0. If an
+unrecoverable error occurs (i.e. no valid file system image has been produced),
+it will exit with exit code 1. If any errors have occurred (e.g. not all input
+files could be read), the exit code will be 2.
+
 ## CATEGORIZERS
 
 Categorizers will inspect the input files in the scanning phase and try to

src/mkdwarfs_main.cpp

@@ -1376,7 +1376,7 @@ int mkdwarfs_main(int argc, sys_char** argv, iolayer const& iol) {
        << err.str();
   }
 
-  return prog.errors > 0;
+  return prog.errors > 0 ? 2 : 0;
 }
 
 int mkdwarfs_main(int argc, sys_char** argv) {

test/tool_main_test.cpp

@@ -634,7 +634,7 @@ TEST_P(logging_test, fancy_output) {
     mkdwarfs_tester t;
     t.iol->set_terminal_fancy(true);
     t.os->set_access_fail("/somedir/ipsum.py"); // trigger an error
-    EXPECT_EQ(1, t.run("-l1 -i / -o - --categorize --num-workers=8 -S 22 "
+    EXPECT_EQ(2, t.run("-l1 -i / -o - --categorize --num-workers=8 -S 22 "
                        "-L 16M --progress=none --log-level=" +
                        level))
         << t.err();
@@ -1971,7 +1971,7 @@ TEST(mkdwarfs_test, recoverable_errors) {
   {
     mkdwarfs_tester t;
     t.os->set_access_fail("/somedir/ipsum.py");
-    EXPECT_EQ(1, t.run("-i / -o - -l4")) << t.err();
+    EXPECT_EQ(2, t.run("-i / -o - -l4")) << t.err();
     EXPECT_THAT(t.err(),
                 ::testing::HasSubstr("filesystem created with 1 error"));
   }
@@ -1980,7 +1980,7 @@ TEST(mkdwarfs_test, recoverable_errors) {
     mkdwarfs_tester t;
     t.os->set_access_fail("/somedir/ipsum.py");
     t.os->set_access_fail("/baz.pl");
-    EXPECT_EQ(1, t.run("-i / -o - -l4")) << t.err();
+    EXPECT_EQ(2, t.run("-i / -o - -l4")) << t.err();
     EXPECT_THAT(t.err(),
                 ::testing::HasSubstr("filesystem created with 2 errors"));
   }