Add backwards compatibility

ruff_lsp/server.py

@@ -113,7 +113,10 @@ class VersionModified(NamedTuple):
 # Require at least Ruff v0.0.291 for formatting, but allow older versions for linting.
 VERSION_REQUIREMENT_FORMATTER = SpecifierSet(">=0.0.291,<0.2.0")
 VERSION_REQUIREMENT_LINTER = SpecifierSet(">=0.0.189,<0.2.0")
+# Version requirement for use of the "ALL" rule selector
 VERSION_REQUIREMENT_ALL_SELECTOR = SpecifierSet(">=0.0.198,<0.2.0")
+# Version requirement for use of the `--output-format` option
+VERSION_REQUIREMENT_OUTPUT_FORMAT = SpecifierSet(">=0.0.291,<0.2.0")
 
 # Arguments provided to every Ruff invocation.
 CHECK_ARGS = [
@@ -1167,6 +1170,15 @@ async def _run_check_on_document(
         else:
             argv.append(arg)
 
+    # If the Ruff version is sufficiently recent, use the deprecated `--format`
+    # argument instead of `--output-format`.
+    if not VERSION_REQUIREMENT_OUTPUT_FORMAT.contains(
+        executable.version, prereleases=True
+    ):
+        index = argv.index("--output-format")
+        argv.pop(index)
+        argv.insert(index, "--format")
+
     # If we're trying to run a single rule, add it to the command line, and disable
     # all other rules (if the Ruff version is sufficiently recent).
     if only: