3 files changed, 103 insertions, 0 deletions
diff --git a/taskcluster/gecko_taskgraph/optimize/mozlint.py b/taskcluster/gecko_taskgraph/optimize/mozlint.py
new file mode 100644
index 0000000000..0fe42ea70d
--- /dev/null
+++ b/taskcluster/gecko_taskgraph/optimize/mozlint.py
@@ -0,0 +1,96 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+import logging
+from pathlib import Path
+from typing import List, Union
+
+from mozlint.parser import Parser
+from mozlint.pathutils import filterpaths
+from taskgraph.optimize.base import OptimizationStrategy
+from taskgraph.util.path import match as match_path
+
+from gecko_taskgraph import GECKO
+
+logger = logging.getLogger(__name__)
+
+
+class TGMozlintParser(Parser):
+    """
+    Mozlint Parser that skips validation. This is needed because decision
+    tasks use sparse clones and the files themselves are not present.
+    """
+
+    def _validate(self, linter):
+        pass
+
+
+class SkipUnlessMozlint(OptimizationStrategy):
+    """
+    Optimization strategy for mozlint tests.
+
+    Uses the mozlint YAML file for each test to determine whether or not a test
+    should run.
+
+    Using:
+        - The optimization relies on having `files_changed` set in the decision task
+          parameters.
+        - Register with register_strategy. The argument is the path to MozLint YAML
+          configuration files ("/tools/lint" for mozilla-central):
+        - In source-test/mozlint.yml, set the optimization strategy for each job by filename:
+        - For Mozlint jobs that run multiple linters at once use a list of filenames:
+    """
+
+    def __init__(self, linters_path: str):
+        self.mozlint_parser = TGMozlintParser(GECKO)
+        self.linters_path = Path(GECKO) / linters_path
+
+    def should_remove_task(
+        self, task, params, mozlint_confs: Union[str, List[str]]
+    ) -> bool:
+        include = []
+        exclude = []
+        extensions = []
+        exclude_extensions = []
+        support_files = ["python/mozlint/**", "tools/lint/**"]
+
+        files_changed = params["files_changed"]
+
+        if isinstance(mozlint_confs, str):
+            mozlint_confs = [mozlint_confs]
+
+        for mozlint_conf in mozlint_confs:
+            mozlint_yaml = str(self.linters_path / mozlint_conf)
+            logger.info(f"Loading file patterns for {task.label} from {mozlint_yaml}.")
+            linter_config = self.mozlint_parser(mozlint_yaml)
+
+            for config in linter_config:
+                include += config.get("include", [])
+                exclude += config.get("exclude", [])
+                extensions += [e.strip(".") for e in config.get("extensions", [])]
+                exclude_extensions += [
+                    e.strip(".") for e in config.get("exclude_extensions", [])
+                ]
+                support_files += config.get("support-files", [])
+
+        # Support files may not be part of "include" patterns, so check first
+        # Do not remove (return False) if any changed
+        for pattern in set(support_files):
+            for path in files_changed:
+                if match_path(path, pattern):
+                    return False
+
+        to_lint, to_exclude = filterpaths(
+            GECKO,
+            list(files_changed),
+            include=include,
+            exclude=exclude,
+            extensions=extensions,
+            exclude_extensions=exclude_extensions,
+        )
+
+        # to_lint should be an empty list if there is nothing to check
+        if not to_lint:
+            return True
+        return False
diff --git a/taskcluster/gecko_taskgraph/optimize/schema.py b/taskcluster/gecko_taskgraph/optimize/schema.py
index a7f878cf60..a348fb177c 100644
--- a/taskcluster/gecko_taskgraph/optimize/schema.py
+++ b/taskcluster/gecko_taskgraph/optimize/schema.py
@@ -39,6 +39,8 @@ default_optimizations = (
     {"upload-symbols": None},
     # optimize strategy alias for reprocess-symbols tasks
     {"reprocess-symbols": None},
+    # optimization strategy for mozlint tests
+    {"skip-unless-mozlint": voluptuous.Any(str, [str])},
 )
 
 OptimizationSchema = voluptuous.Any(*default_optimizations)
diff --git a/taskcluster/gecko_taskgraph/optimize/strategies.py b/taskcluster/gecko_taskgraph/optimize/strategies.py
index ffc395385b..f1ade38672 100644
--- a/taskcluster/gecko_taskgraph/optimize/strategies.py
+++ b/taskcluster/gecko_taskgraph/optimize/strategies.py
@@ -11,6 +11,8 @@ from mozbuild.util import memoize
 from taskgraph.optimize.base import OptimizationStrategy, register_strategy
 from taskgraph.util.path import match as match_path
 
+from gecko_taskgraph.optimize.mozlint import SkipUnlessMozlint
+
 logger = logging.getLogger(__name__)
 
 
@@ -100,3 +102,6 @@ class SkipUnlessChanged(OptimizationStrategy):
             )
             return True
         return False
+
+
+register_strategy("skip-unless-mozlint", args=("tools/lint",))(SkipUnlessMozlint)