From f6a356601c0d100c967a43c8b296115c35f8ddf8 Mon Sep 17 00:00:00 2001
From: Chris H-C <chutten@mozilla.com>
Date: Thu, 18 Apr 2024 16:42:25 -0400
Subject: [PATCH] bug 1886810 - Forbid (by lint) non-ping lifetimes for
 _distribution metrics

---
 CHANGELOG.md          |  2 ++
 glean_parser/lint.py  | 16 ++++++++++++++++
 tests/data/gecko.yaml |  4 ----
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 556ab5367..988f88beb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
 # Changelog
 
+- NEW LINT: Forbid (via lint) non-ping lifetimes for `*_distribution` metrics ([bug 1886810](https://bugzilla.mozilla.org/show_bug.cgi?id=1886810))
+
 ## 14.0.1
 
 - BUGFIX: Fix missing `ping_arg` in util.py ([#687](https://github.com/mozilla/glean_parser/pull/687))
diff --git a/glean_parser/lint.py b/glean_parser/lint.py
index 891d05ad6..be38bd849 100644
--- a/glean_parser/lint.py
+++ b/glean_parser/lint.py
@@ -385,6 +385,21 @@ def check_unknown_ping(
                 yield nit
 
 
+def check_distribution_lifetime(
+    metric: metrics.Metric, parser_config: Dict[str, Any]
+) -> LintGenerator:
+    """*_distribution metrics should only be ping-lifetime, because otherwise
+    we will send the same samples more than once."""
+    if (
+        metric.type.endswith("_distribution")
+        and metric.lifetime != metrics.Lifetime.ping
+    ):
+        yield (
+            "Distribution metrics ought to have ping lifetime. Otherwise, their"
+            " samples could be submitted multiple times."
+        )
+
+
 # The checks that operate on an entire category of metrics:
 #    {NAME: (function, is_error)}
 CATEGORY_CHECKS: Dict[
@@ -412,6 +427,7 @@ def check_unknown_ping(
     "METRIC_ON_EVENTS_LIFETIME": (check_metric_on_events_lifetime, CheckType.error),
     "UNEXPECTED_UNIT": (check_unexpected_unit, CheckType.warning),
     "EMPTY_DATAREVIEW": (check_empty_datareview, CheckType.warning),
+    "DISTRIBUTION_NON_PING_LIFETIME": (check_distribution_lifetime, CheckType.error),
 }
 
 
diff --git a/tests/data/gecko.yaml b/tests/data/gecko.yaml
index 2fc0cd684..552d35052 100644
--- a/tests/data/gecko.yaml
+++ b/tests/data/gecko.yaml
@@ -9,7 +9,6 @@ page.perf:
     type: timing_distribution
     gecko_datapoint: GV_PAGE_LOAD_MS
     time_unit: millisecond
-    lifetime: application
     description: >
       A sample timing distribution metric exported from Gecko.
     bugs:
@@ -24,7 +23,6 @@ page.perf:
     type: timing_distribution
     gecko_datapoint: GV_PAGE_RELOAD_MS
     time_unit: millisecond
-    lifetime: application
     description: >
       Another sample timing distribution metric exported from Gecko.
     bugs:
@@ -62,7 +60,6 @@ gfx.content.checkerboard:
     type: timing_distribution
     gecko_datapoint: CHECKERBOARD_DURATION
     time_unit: millisecond
-    lifetime: application
     description: >
       A sample timing distribution metric exported from Gecko.
     bugs:
@@ -121,7 +118,6 @@ non.gecko.metrics:
   app_load_time:
     type: timing_distribution
     time_unit: millisecond
-    lifetime: application
     description: >
       A sample timing distribution that is not tied to a Gecko datapoint.
     bugs: