Make a few helmfile sub-commands consistently support needs-related flags (#78)

* Make a few helmfile sub-commands to consistently support needs-related flags

* helmfile-diff adds support for --include-transitive-needs
* helmfile-template adds support for --skip-needs
* helmfile-lint adds support for --skip-needs, --include-needs, and --include-transitive-needs

Ref https://github.com/roboll/helmfile/issues/2055

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Fix a few helmfile-lint needs related bugs and add tests

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Is include-transitive-needs realy working as intended? 🤔

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Confirm that it does fail on unselected need by default

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Add missing testdata

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Test helmfile-template for include/skip needs support

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Fix a few terms

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Add more tests to better know the current helmfile-diff behavior around needs

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Fix failing tests

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Fix helmfile-diff to consistently handle skip/include-needs

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Extract testhelper.RequireLog for reusing

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Fix all bugs and test cases for TestDiff and TestDiff_2

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Fix TestDiff_2

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Fix TestDiff

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Fix TestDiffWithNeeds

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Unify behavior on including disabled releases as needs for lint and template

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

* Fix bug that --include-transitive-needs does not imply include-needs

Signed-off-by: Yusuke Kuoka <ykuoka@gmail.com>

cmd/diff.go

@@ -44,6 +44,10 @@ func addDiffSubcommand(cliApp *cli.App) {
 				Name:  "include-needs",
 				Usage: `automatically include releases from the target release's "needs" when --selector/-l flag is provided. Does nothing when when --selector/-l flag is not provided`,
 			},
+			cli.BoolFlag{
+				Name:  "include-transitive-needs",
+				Usage: `like --include-needs, but also includes transitive needs (needs of needs). Does nothing when when --selector/-l flag is not provided. Overrides exclusions of other selectors and conditions.`,
+			},
 			cli.BoolFlag{
 				Name:  "skip-diff-on-install",
 				Usage: "Skips running helm-diff on releases being newly installed on this apply. Useful when the release manifests are too huge to be reviewed, or it's too time-consuming to diff at all",