DI: normalize Windows backslashes in CodeTracker suffix-stripping loops

p-ddsign · claude · p-ddsign · commit a4298f6a9bcf · 2026-05-13T12:33:38.000-04:00
The DEBUG-5111 Windows path fix was incomplete: Utils.path_matches_suffix?
normalizes backslashes internally, but CodeTracker#iseqs_for_path_suffix
and #resolve_path_suffix have their own suffix-shortening loops that check
working_suffix.include?('/') and strip via %r{.*/+}. When the probe path
contains only backslashes (e.g. shared\rails\app\foo.rb sent by IDE tooling
on Windows), the loop's '/' check is false, so the stripping never fires.
With no stripping, only the full suffix is tested against registry paths;
the typical Linux deployment doesn't have the source-repo prefix
(shared/rails/) in its filesystem paths, so the match fails and the probe
stays at RECEIVED instead of progressing to INSTALLED.

Surfaced via the system test test_probe_status_log_line_with_windows_path
in DataDog/system-tests, which sends sourceFile with backslashes against a
Rails weblog whose runtime paths lack the shared/rails/ prefix.

Fix: normalize backslashes upfront in both functions before the stripping
loop, mirroring the pattern Utils.path_can_match_spec? already uses.

Spec coverage in spec/datadog/di/code_tracker_spec.rb covers:
- Windows-style probe path with prefix stripping required (the failing case)
- Windows-style + uppercase, exercising both backslash normalization and
  the case-insensitive fallback
- Absolute Windows-style path

Verified: 3 new specs pass; full code_tracker_spec/utils_spec/instrumenter_spec/
probe_spec suite (203 examples) passes; standardrb clean; steep clean.

Co-Authored-By: Claude &lt;noreply@anthropic.com&gt;
diff --git a/lib/datadog/di/code_tracker.rb b/lib/datadog/di/code_tracker.rb
@@ -249,6 +249,11 @@ def iseqs_for_path_suffix(suffix)
           exact = registry[suffix]
           return [suffix, exact] if exact
 
+          # Normalize Windows-style backslash separators (DEBUG-5111) upfront
+          # so the suffix-shortening loop's "/+" regex can strip leading
+          # components on probes whose sourceFile uses backslashes.
+          suffix = Utils.normalize_windows_separators(suffix)
+
           # Per the design comment in utils.rb, attempt case-sensitive
           # matching first (steps 5-6) and only fall back to case-insensitive
           # matching (steps 7-8) when no case-sensitive match is found.
@@ -371,6 +376,11 @@ def resolve_path_suffix(suffix, paths)
         # Exact match.
         return suffix if paths.include?(suffix)
 
+        # Normalize Windows-style backslash separators (DEBUG-5111) upfront
+        # so the suffix-shortening loop's "/+" regex can strip leading
+        # components on probes whose sourceFile uses backslashes.
+        suffix = Utils.normalize_windows_separators(suffix)
+
         # Suffix match. Per the design comment in utils.rb, attempt
         # case-sensitive matching first (steps 5-6) and only fall back to
         # case-insensitive (steps 7-8) when no case-sensitive match is found.
diff --git a/spec/datadog/di/code_tracker_spec.rb b/spec/datadog/di/code_tracker_spec.rb
@@ -652,6 +652,44 @@
     end
   end
 
+  describe "#iseqs_for_path_suffix with Windows backslash suffix" do
+    # Verifies that backslash separators (DEBUG-5111) are normalized upfront so
+    # the suffix-shortening loop can strip leading components. Probe paths from
+    # IDE tooling on Windows arrive with backslashes; the runtime registry path
+    # has forward slashes and typically lacks the leading directory components
+    # of the source repository path.
+    around do |example|
+      tracker.define_singleton_method(:backfill_registry) {}
+      tracker.start
+
+      registry = tracker.send(:registry)
+      # Runtime path on the deployed weblog — no shared/rails/ prefix.
+      registry["/app/controllers/debugger_controller.rb"] = "/app/controllers/debugger_controller.rb"
+
+      example.run
+
+      tracker.stop
+    end
+
+    it "matches when the probe path uses backslashes and needs prefix stripping" do
+      expect(
+        tracker.iseqs_for_path_suffix('shared\rails\app\controllers\debugger_controller.rb'),
+      ).to eq(["/app/controllers/debugger_controller.rb", "/app/controllers/debugger_controller.rb"])
+    end
+
+    it "matches when the probe path uses backslashes and uppercase, needing both fallbacks" do
+      expect(
+        tracker.iseqs_for_path_suffix('SHARED\RAILS\APP\CONTROLLERS\DEBUGGER_CONTROLLER.RB'),
+      ).to eq(["/app/controllers/debugger_controller.rb", "/app/controllers/debugger_controller.rb"])
+    end
+
+    it "matches when the probe path is an absolute Windows-style path" do
+      expect(
+        tracker.iseqs_for_path_suffix('\app\controllers\debugger_controller.rb'),
+      ).to eq(["/app/controllers/debugger_controller.rb", "/app/controllers/debugger_controller.rb"])
+    end
+  end
+
   describe '#iseq_for_line' do
     before do
       allow(Datadog::DI).to receive(:respond_to?).and_call_original
