[flake8-datetimez] Allow timezone-safe strptime chains (DTZ007)

crates/ruff_linter/resources/mdtest/flake8-datetimez/call-datetime-strptime-without-zone.md

@@ -0,0 +1,39 @@
+# `call-datetime-strptime-without-zone` (`DTZ007`)
+
+```toml
+lint.select = ["DTZ007"]
+```
+
+## Replacing fields before converting the timezone
+
+Calling `astimezone` produces an aware datetime even when one or more `replace` calls precede it.
+
+```py
+from datetime import datetime, timezone
+
+datetime.strptime("2026", "%Y").replace(microsecond=0).astimezone()
+datetime.strptime("2026", "%Y").replace(hour=12).replace(minute=30).astimezone(timezone.utc)
+datetime.strptime("2026", "%Y").replace(tzinfo=None).astimezone()
+```
+
+## Replacements that leave a naive datetime
+
+A replacement without a timezone conversion still produces a naive datetime.
+
+```py
+from datetime import datetime
+
+datetime.strptime("2026", "%Y").replace(microsecond=0)  # error: [call-datetime-strptime-without-zone]
+datetime.strptime("2026", "%Y").replace(tzinfo=None)  # error: [call-datetime-strptime-without-zone]
+```
+
+## Passing a method to another call
+
+Passing the `replace` method to another object's method does not convert the parsed datetime.
+
+```py
+from datetime import datetime
+
+def convert(converter):
+    converter.replace(datetime.strptime("2026", "%Y").replace).astimezone()  # error: [call-datetime-strptime-without-zone]
+```

crates/ruff_linter/src/rules/flake8_datetimez/rules/call_datetime_strptime_without_zone.rs

@@ -6,7 +6,7 @@ use ruff_text_size::Ranged;
 use crate::Violation;
 use crate::checkers::ast::Checker;
 
-use crate::rules::flake8_datetimez::helpers::DatetimeModuleAntipattern;
+use crate::rules::flake8_datetimez::helpers::{self, DatetimeModuleAntipattern};
 
 /// ## What it does
 /// Checks for uses of `datetime.datetime.strptime()` that lead to naive
@@ -104,6 +104,10 @@ pub(crate) fn call_datetime_strptime_without_zone(checker: &Checker, call: &ast:
         return;
     }
 
+    if helpers::followed_by_astimezone(checker) {
+        return;
+    }
+
     // Does the `strptime` call contain a format string with a timezone specifier?
     if let Some(expr) = call.arguments.args.get(1) {
         match expr {
@@ -155,10 +159,6 @@ fn find_antipattern(
     let Some(Expr::Attribute(ast::ExprAttribute { attr, .. })) = parent else {
         return Some(DatetimeModuleAntipattern::NoTzArgumentPassed);
     };
-    // Ex) `datetime.strptime(...).astimezone()`
-    if attr == "astimezone" {
-        return None;
-    }
     if attr != "replace" {
         return Some(DatetimeModuleAntipattern::NoTzArgumentPassed);
     }