fix(diff): preserve diff side for review comment locations

cmd/opencodereview/output.go

@@ -98,7 +98,11 @@ func renderComment(comment model.LlmComment, out io.Writer) {
 		return
 	}
 
-	fmt.Fprintf(out, "\n%s\n", colorf("\033[2m", "─── %s:%d-%d ───", sanitizeTerminal(comment.Path), comment.StartLine, comment.EndLine))
+	location := fmt.Sprintf("%s:%d-%d", sanitizeTerminal(comment.Path), comment.StartLine, comment.EndLine)
+	if comment.Side == model.CommentSideLeft {
+		location += " [LEFT]"
+	}
+	fmt.Fprintf(out, "\n%s\n", colorf("\033[2m", "─── %s ───", location))
 
 	if comment.Content != "" {
 		badge := buildBadge(comment)

cmd/opencodereview/output_helpers_test.go

@@ -562,6 +562,21 @@ func TestRenderComment_ContentOnly(t *testing.T) {
 	}
 }
 
+func TestRenderComment_LeftSideShowsDiffSide(t *testing.T) {
+	got := captureStdout(t, func() {
+		renderComment(model.LlmComment{
+			Path:      "deleted.go",
+			StartLine: 5,
+			EndLine:   5,
+			Side:      model.CommentSideLeft,
+			Content:   "review the removed call",
+		}, os.Stdout)
+	})
+	if !strings.Contains(got, "deleted.go:5-5 [LEFT]") {
+		t.Errorf("expected old-side marker, got %q", got)
+	}
+}
+
 func TestRenderComment_WithDiff(t *testing.T) {
 	got := captureStdout(t, func() {
 		renderComment(model.LlmComment{

cmd/opencodereview/sarif.go

@@ -71,6 +71,7 @@ type sarifResult struct {
 
 type sarifLocation struct {
 	PhysicalLocation sarifPhysicalLocation `json:"physicalLocation"`
+	Properties       map[string]string     `json:"properties,omitempty"`
 }
 
 type sarifPhysicalLocation struct {
@@ -214,17 +215,18 @@ func sarifResults(comments []model.LlmComment) []sarifResult {
 // mapping follows FR-3 in the requirements spec:
 //   - Path          → locations[].physicalLocation.artifactLocation.uri
 //   - StartLine/EndLine (valid range) → locations[].physicalLocation.region
+//   - Side          → locations[].properties.side (LEFT or RIGHT)
 //   - Content       → message.text
 //   - Category (or "other") → ruleId
 //   - Severity      → level
 //   - SuggestionCode + ExistingCode + valid region → fixes
 //   - Path + Category + ExistingCode → partialFingerprints (stable fingerprint)
 //
-// Fixes are only emitted when a valid region exists (StartLine > 0 &&
-// EndLine >= StartLine), because replacement.deletedRegion is required by
-// the SARIF schema and cannot be omitted. When the region is invalid (zero
-// or inverted), the suggestion is still conveyed in message.text but no
-// machine-readable fix is emitted.
+// Fixes are only emitted for a valid RIGHT-side region (StartLine > 0 &&
+// EndLine >= StartLine), because replacement.deletedRegion describes the
+// current artifact and cannot safely represent code that only exists on the
+// LEFT side. When the region is invalid or LEFT-sided, the suggestion is
+// still conveyed in message.text but no machine-readable fix is emitted.
 func sarifResultFromComment(c model.LlmComment) sarifResult {
 	category := c.Category
 	if category == "" {
@@ -246,6 +248,9 @@ func sarifResultFromComment(c model.LlmComment) sarifResult {
 				ArtifactLocation: sarifArtifactLocation{URI: c.Path},
 			},
 		}
+		if c.Side != "" {
+			loc.Properties = map[string]string{"side": c.Side}
+		}
 		if hasRegion {
 			loc.PhysicalLocation.Region = &sarifRegion{
 				StartLine: c.StartLine,
@@ -258,7 +263,7 @@ func sarifResultFromComment(c model.LlmComment) sarifResult {
 	// Fixes require: non-empty SuggestionCode, non-empty ExistingCode, non-empty
 	// Path, AND a valid region. The region is needed because deletedRegion is
 	// required by the SARIF schema — omitting it invalidates the entire document.
-	if c.SuggestionCode != "" && c.ExistingCode != "" && c.Path != "" && hasRegion {
+	if c.Side != model.CommentSideLeft && c.SuggestionCode != "" && c.ExistingCode != "" && c.Path != "" && hasRegion {
 		rep := sarifReplacement{
 			DeletedRegion: sarifRegion{
 				StartLine: c.StartLine,

cmd/opencodereview/sarif_test.go

@@ -203,6 +203,35 @@ func TestOutputSARIF_FullFieldMapping(t *testing.T) {
 	}
 }
 
+func TestOutputSARIF_LeftSideCarriesSideAndOmitsFix(t *testing.T) {
+	comment := model.LlmComment{
+		Path:           "main.go",
+		Content:        "The removed call was not replaced safely.",
+		SuggestionCode: "replacement()",
+		ExistingCode:   "legacyCall()",
+		StartLine:      2,
+		EndLine:        2,
+		Side:           model.CommentSideLeft,
+	}
+	out := captureStdout(t, func() {
+		if err := outputSARIF([]model.LlmComment{comment}, "v1", nil, nil, os.Stdout); err != nil {
+			t.Fatalf("outputSARIF: %v", err)
+		}
+	})
+	doc := mustUnmarshal(t, out)
+	result := mustGetResult(t, doc)
+
+	locations := result["locations"].([]any)
+	location := locations[0].(map[string]any)
+	properties := location["properties"].(map[string]any)
+	if properties["side"] != model.CommentSideLeft {
+		t.Fatalf("location side = %v, want %q", properties["side"], model.CommentSideLeft)
+	}
+	if _, ok := result["fixes"]; ok {
+		t.Fatal("deleted-side comment must not emit a current-file SARIF fix")
+	}
+}
+
 // --- AC-5 & AC-6: Severity → Level mapping ---
 
 func TestSarifSeverityLevel(t *testing.T) {

examples/gerrit_ci/post_review.py

@@ -117,6 +117,10 @@ def build_review_input(result):
         line = c.get("end_line") or 0
         if line > 0:
             entry["line"] = line
+            # Gerrit CommentInput defaults to the revision (new) side. A LEFT
+            # coordinate belongs to the change's parent/base patchset.
+            if str(c.get("side", "")).upper() == "LEFT":
+                entry["side"] = "PARENT"
         grouped.setdefault(path, []).append(entry)
 
     if comments:
@@ -171,7 +175,11 @@ def fold_comments(review_input):
     ]
     for path, entries in (review_input.get("comments") or {}).items():
         for e in entries:
-            loc = "`%s:%d`" % (path, e["line"]) if "line" in e else "`%s`" % path
+            if "line" in e:
+                side_label = " (old file)" if e.get("side") == "PARENT" else ""
+                loc = "`%s:%d%s`" % (path, e["line"], side_label)
+            else:
+                loc = "`%s`" % path
             parts.append("\n---\n\n%s\n\n%s" % (loc, e["message"]))
     full = "\n".join(parts)
     if len(full) > MAX_MESSAGE_LEN:

examples/gerrit_ci/post_review_test.py

@@ -68,6 +68,11 @@ def assert_line(self, c, want_line):
     def test_single_line_comment(self):
         self.assert_line(comment(start_line=6, end_line=6), 6)
 
+    def test_left_side_uses_parent(self):
+        entry = entry_of(build([comment(side="LEFT")]))
+        self.assertEqual(entry["line"], 6)
+        self.assertEqual(entry["side"], "PARENT")
+
     def test_multi_line_range(self):
         self.assert_line(comment(start_line=3, end_line=6), 6)
 

examples/gitflic_ci/README.md

@@ -50,7 +50,7 @@ Create a token in **User Settings → Access Tokens** (or a dedicated service ac
 
 ## Notes & Limitations
 
-- **Inline positioning** — GitFlic requires all four of `newLine`/`oldLine`/`newPath`/`oldPath` for a code comment; if any is missing it silently creates a general comment. `post_review.py` computes the old-side position from the same merge-base diff the review ran on (`git diff merge-base(from, to)..to`), and anchors added lines to the closest preceding old line.
+- **Inline positioning** — GitFlic requires all four of `newLine`/`oldLine`/`newPath`/`oldPath` for a code comment; if any is missing it silently creates a general comment. `post_review.py` computes the old-side position from the same merge-base diff the review ran on (`git diff merge-base(from, to)..to`), and anchors added lines to the closest preceding old line. GitFlic has no side selector for LEFT/base coordinates, so those comments are placed in the fallback summary instead of being attached to a potentially incorrect new-side line.
 - **Rate limit** — the GitFlic cloud API allows 500 requests/hour per token. One review posts `comments + 2` requests at most, which fits comfortably.
 - **Self-hosted GitFlic** — set `GITFLIC_API_URL` to your instance's REST API base URL.
 - **Re-reviews** — every push to the MR triggers a new pipeline and a new review. To skip already-reviewed MRs, check existing discussions for the `OpenCodeReview` marker before running the review step.

examples/gitflic_ci/post_review.py

@@ -17,9 +17,10 @@
 GitFlic's Discussions API needs an *old-side* line even for a comment on the new
 side of the diff: an inline (code) discussion requires all four of
 newLine/oldLine/newPath/oldPath, otherwise GitFlic silently records a plain
-comment. `ocr review` only reports new-side positions, so this script computes
-the old-side line itself by parsing the same merge-base diff the review ran on
-(`git diff merge-base(from, to)..to`).
+comment. For RIGHT-side comments, this script computes the old-side line itself
+by parsing the same merge-base diff the review ran on (`git diff
+merge-base(from, to)..to`). GitFlic has no side selector, so LEFT-side comments
+are kept in the fallback summary instead of being attached to the wrong file.
 
 Standard library only (json, urllib, subprocess) so it runs on the stock
 node:20 / python image used by the pipeline.
@@ -167,7 +168,7 @@ def flush():
 
 
 # --------------------------------------------------------------------------- #
-# Line mapping (new file side -> old file side)
+# Line mapping (RIGHT/new file side -> old file side)
 # --------------------------------------------------------------------------- #
 
 
@@ -235,7 +236,8 @@ def format_comment_fallback(c):
     start_line = c.get("start_line", 0)
     end_line = c.get("end_line", 0)
     if start_line and end_line:
-        md += " (L%d-L%d)" % (start_line, end_line)
+        side_label = " (old file)" if str(c.get("side", "")).upper() == "LEFT" else ""
+        md += " (L%d-L%d%s)" % (start_line, end_line, side_label)
     md += "\n\n" + c.get("content", "")
     suggestion = c.get("suggestion_code", "")
     existing = c.get("existing_code", "")
@@ -269,6 +271,13 @@ def publish(result, diffs_by_path, post):
     for c in comments:
         path = c.get("path", "")
         end_line = c.get("end_line", 0) or 0
+        # GitFlic's discussion API has no side selector. Posting a LEFT-side
+        # coordinate as newLine would silently annotate the wrong revision, so
+        # keep it in the summary fallback until the API can represent it.
+        if str(c.get("side", "")).upper() == "LEFT":
+            log("left-side comment for %s cannot be positioned by GitFlic; folding into summary" % path)
+            failed.append(c)
+            continue
         fd = diffs_by_path.get(path)
         if fd is None:
             log("no diff for %s; folding comment into the summary note" % path)

examples/gitflic_ci/post_review_test.py

@@ -113,6 +113,17 @@ def test_pure_addition_at_top(self):
         self.assertEqual(pr.old_line_for(hunks, 1), 1)
 
 
+class PublishSideTest(unittest.TestCase):
+    def test_left_side_falls_back_to_summary(self):
+        posted = []
+        result = {"comments": [{"path": "main.go", "content": "old", "start_line": 3, "end_line": 3, "side": "LEFT"}]}
+        stats = pr.publish(result, {"main.go": pr.FileDiff("main.go", "main.go")}, posted.append)
+        self.assertEqual(stats["inline"], 0)
+        self.assertEqual(stats["fallback"], 1)
+        self.assertNotIn("newLine", posted[0])
+        self.assertIn("old file", posted[0]["message"])
+
+
 class ParseDiffTest(unittest.TestCase):
     def test_modified_file(self):
         fd = pr.parse_diff(SAMPLE_DIFF)[0]