Document syntax-check as unskippable

Fixes: #1594

src/ansiblelint/__main__.py

@@ -118,7 +118,7 @@ def initialize_options(arguments: Optional[List[str]] = None) -> None:
     )
 
 
-def report_outcome(
+def report_outcome(  # noqa: C901
     result: "LintResult", options: Namespace, mark_as_success: bool = False
 ) -> int:
     """Display information about how to skip found rules.
@@ -127,10 +127,7 @@ def report_outcome(
     """
     failures = 0
     warnings = 0
-    msg = """\
-# .ansible-lint
-warn_list:  # or 'skip_list' to silence them completely
-"""
+    msg = ""
     matches_unignored = [match for match in result.matches if not match.ignored]
 
     # counting
@@ -141,6 +138,11 @@ def report_outcome(
         else:
             warnings += 1
 
+    # remove unskippable rules from the list
+    for rule_id in list(matched_rules.keys()):
+        if 'unskippable' in matched_rules[rule_id].tags:
+            matched_rules.pop(rule_id)
+
     entries = []
     for key in sorted(matched_rules.keys()):
         if {key, *matched_rules[key].tags}.isdisjoint(options.warn_list):
@@ -149,7 +151,16 @@ def report_outcome(
         if "experimental" in match.rule.tags:
             entries.append("  - experimental  # all rules tagged as experimental\n")
             break
-    msg += "".join(sorted(entries))
+    if entries:
+        console_stderr.print(
+            "You can skip specific rules or tags by adding them to your "
+            "configuration file:"
+        )
+        msg += """\
+# .ansible-lint
+warn_list:  # or 'skip_list' to silence them completely
+"""
+        msg += "".join(sorted(entries))
 
     # Do not deprecate the old tags just yet. Why? Because it is not currently feasible
     # to migrate old tags to new tags. There are a lot of things out there that still
@@ -167,10 +178,6 @@ def report_outcome(
     #     )
 
     if result.matches and not options.quiet:
-        console_stderr.print(
-            "You can skip specific rules or tags by adding them to your "
-            "configuration file:"
-        )
         console_stderr.print(render_yaml(msg))
         console_stderr.print(
             f"Finished with {failures} failure(s), {warnings} warning(s) "

src/ansiblelint/rules/AnsibleSyntaxCheckRule.py

@@ -13,6 +13,19 @@
 from ansiblelint.rules import AnsibleLintRule
 from ansiblelint.text import strip_ansi_escape
 
+DESCRIPTION = """
+Running ansible-playbook --syntax-check ... reported an error.
+
+This error is caused by `ansible-playbook --syntax-check` failing to run and
+cannot be disabled as passing it is a prerequisite for other steps. You can
+either exclude these files from linting or better assure they can be loaded
+by Ansible. This is often achieved by editing inventory file and/or
+`ansible.cfg` so ansible can load required variables.
+
+If undefined variables are the failure reason you could use jinja default()
+filter in order to provide fallbacks.
+"""
+
 _ansible_syntax_check_re = re.compile(
     r"^ERROR! (?P<title>[^\n]*)\n\nThe error appears to be in "
     r"'(?P<filename>.*)': line (?P<line>\d+), column (?P<column>\d+)",
@@ -29,9 +42,9 @@ class AnsibleSyntaxCheckRule(AnsibleLintRule):
 
     id = "syntax-check"
     shortdesc = "Ansible syntax check failed"
-    description = "Running ansible-playbook --syntax-check ... reported an error."
+    description = DESCRIPTION
     severity = "VERY_HIGH"
-    tags = ["core"]
+    tags = ["core", "unskippable"]
     version_added = "v5.0.0"
 
     @staticmethod