skip diffs with no package changes

Author: anna-oake

dist/index.js

@@ -62018,6 +62018,10 @@ const hasDixChanges = (diff) => {
 	if (!baseMatch || !prMatch) return true;
 	return baseMatch[1].trim() !== prMatch[1].trim();
 };
+const hasPackageChanges = (diff) => {
+	if (!diff || diff.trim() === "") return false;
+	return diff.split(/\r?\n/).length > 5;
+};
 var NIX_DIFF_ACTION_MARKER_BASE = "<!-- nix-diff-action";
 var getNixDiffActionMarker = (displayName) => displayName ? `${NIX_DIFF_ACTION_MARKER_BASE}:${displayName} -->` : `${NIX_DIFF_ACTION_MARKER_BASE} -->`;
 var MAX_COMMENT_LENGTH = 6e4;
@@ -62043,12 +62047,11 @@ const checkIfAnyDiffTruncated = (results) => {
 	return results.some((r$1) => r$1.diff.length > maxLength);
 };
 const formatAggregatedComment = (results, headSha, options) => {
-	const visibleResults = results.filter((r$1) => hasDixChanges(r$1.diff));
-	const maxDiffLength = calculateMaxDiffPerAttribute(visibleResults.length);
-	return `${visibleResults.length === 1 ? getNixDiffActionMarker(visibleResults[0].displayName) : getNixDiffActionMarker()}
+	const maxDiffLength = calculateMaxDiffPerAttribute(results.length);
+	return `${results.length === 1 ? getNixDiffActionMarker(results[0].displayName) : getNixDiffActionMarker()}
 ## Nix Diff
 
-${visibleResults.map((result) => {
+${results.map((result) => {
 		const { truncated, text } = truncateDiff(result.diff || "No differences found", maxDiffLength);
 		const artifactHint = truncated && options?.runId && options?.repoUrl ? `\n\n> **Note**: Diff was truncated. [View full diff in artifacts](${options.repoUrl}/actions/runs/${options.runId})` : "";
 		return `<details>
@@ -62131,10 +62134,10 @@ var GitHubService = class extends Service()("GitHubService", { succeed: {
 	}),
 	createOctokit: (token) => import_github.getOctokit(token),
 	postAggregatedComment: (octokit, context$2, pr, results, options, formatOptions) => gen(function* () {
-		const hasChanges = results.some((r$1) => hasDixChanges(r$1.diff));
-		const commentBody = formatAggregatedComment(results, pr.head.sha, formatOptions);
-		const displayName = results.length === 1 ? results[0].displayName : void 0;
-		if (options.skipNoChange && !hasChanges) return yield* logInfo("No differences found. Skipping comment (skip-no-change is enabled).");
+		const visibleResults = results.filter((r$1) => hasDixChanges(r$1.diff) && hasPackageChanges(r$1.diff));
+		if (options.skipNoChange && visibleResults.length === 0) return yield* logInfo("No meaningful differences found. Skipping comment (skip-no-change is enabled).");
+		const commentBody = formatAggregatedComment(visibleResults, pr.head.sha, formatOptions);
+		const displayName = visibleResults.length === 1 ? visibleResults[0].displayName : void 0;
 		if (options.commentStrategy === "update") return yield* match$2(yield* findExistingNixDiffComment(octokit, context$2, pr.number, displayName), {
 			onNone: () => gen(function* () {
 				yield* createComment(octokit, context$2, pr.number, commentBody);

dist/index.js.map

@@ -5,7 +5,7 @@ import { parseCommentStrategy, parseAttributes, validateDirectory } from "./prog
 import { processDiffResults } from "./programs/full.js";
 import { GitService, sanitizeBranchName } from "./services/git.js";
 import { NixService } from "./services/nix.js";
-import { hasDixChanges } from "./services/utils.js";
+import { hasDixChanges, hasPackageChanges } from "./services/utils.js";
 import { createArtifactName } from "./services/artifact.js";
 
 describe("parseAttributes", () => {
@@ -686,3 +686,38 @@ DIFF: 0 bytes`;
     expect(hasDixChanges(diff)).toBe(false);
   });
 });
+
+describe("hasPackageChanges", () => {
+  test("returns false for undefined", () => {
+    expect(hasPackageChanges(undefined)).toBe(false);
+  });
+
+  test("returns false for empty string", () => {
+    expect(hasPackageChanges("")).toBe(false);
+  });
+
+  test("returns false for whitespace only", () => {
+    expect(hasPackageChanges("   \n  ")).toBe(false);
+  });
+
+  test("returns true when package section is present", () => {
+    const diff = `<<< /nix/store/c7hi9s9k8p4gpa941c7z7qzh604dhgwp-nixos-system-lxc-share-lxc-proxmox-26.05.20251225.3e2499d.drv
+>>> /nix/store/77k3zm8172bg5kq3chkpg4hqm9yzcm4k-nixos-system-lxc-share-lxc-proxmox-26.05.20251225.3e2499d.drv
+
+ADDED
+[A.] hello 2.12.2.drv, 2.12.2.tar.gz.drv
+
+SIZE: 18.8 MiB -> 18.8 MiB
+DIFF: 5.48 KiB`;
+    expect(hasPackageChanges(diff)).toBe(true);
+  });
+
+  test("returns false when no package section is present", () => {
+    const diff = `<<< /nix/store/qhhdx5khfpa07zc1lwfxcbrhn4r2g9xm-darwin-system-26.05.c2b3620.drv
+>>> /nix/store/b3g2v8jf13307zkcmip1w6wdxwhhijrp-darwin-system-26.05.c2b3620.drv
+
+SIZE: 260 MiB -> 260 MiB
+DIFF: 32 bytes`;
+    expect(hasPackageChanges(diff)).toBe(false);
+  });
+});

src/main.test.ts

@@ -3,7 +3,7 @@ import { Effect, Option } from "effect";
 import { NotPullRequestContextError, GitHubApiError } from "../errors.js";
 import type { GitHubContext, Octokit, PullRequestPayload, CommentOptions } from "../types.js";
 import type { DiffResult } from "../schemas.js";
-import { hasDixChanges } from "./utils.js";
+import { hasDixChanges, hasPackageChanges } from "./utils.js";
 
 const NIX_DIFF_ACTION_MARKER_BASE = "<!-- nix-diff-action";
 
@@ -70,16 +70,15 @@ export const formatAggregatedComment = (
   headSha: string,
   options?: FormatCommentOptions,
 ): string => {
-  const visibleResults = results.filter((r) => hasDixChanges(r.diff));
-  const maxDiffLength = calculateMaxDiffPerAttribute(visibleResults.length);
+  const maxDiffLength = calculateMaxDiffPerAttribute(results.length);
   // Single attribute: displayName-specific marker for matrix + update strategy
   // Multiple attributes: generic marker (results order may vary in comment-only mode)
   const marker =
-    visibleResults.length === 1
-      ? getNixDiffActionMarker(visibleResults[0].displayName)
+    results.length === 1
+      ? getNixDiffActionMarker(results[0].displayName)
       : getNixDiffActionMarker();
 
-  const sections = visibleResults
+  const sections = results
     .map((result) => {
       const { truncated, text } = truncateDiff(
         result.diff || "No differences found",
@@ -269,17 +268,19 @@ export class GitHubService extends Effect.Service<GitHubService>()("GitHubServic
       formatOptions?: FormatCommentOptions,
     ): Effect.Effect<void, GitHubApiError> =>
       Effect.gen(function* () {
-        const hasChanges = results.some((r) => hasDixChanges(r.diff));
-        const commentBody = formatAggregatedComment(results, pr.head.sha, formatOptions);
-        // Use displayName-specific marker for single attribute
-        const displayName = results.length === 1 ? results[0].displayName : undefined;
-
-        if (options.skipNoChange && !hasChanges) {
+        const visibleResults = results.filter(
+          (r) => hasDixChanges(r.diff) && hasPackageChanges(r.diff),
+        );
+        if (options.skipNoChange && visibleResults.length === 0) {
           return yield* Effect.logInfo(
-            "No differences found. Skipping comment (skip-no-change is enabled).",
+            "No meaningful differences found. Skipping comment (skip-no-change is enabled).",
           );
         }
 
+        const commentBody = formatAggregatedComment(visibleResults, pr.head.sha, formatOptions);
+        // Use displayName-specific marker for single attribute
+        const displayName = visibleResults.length === 1 ? visibleResults[0].displayName : undefined;
+
         if (options.commentStrategy === "update") {
           const existing = yield* findExistingNixDiffComment(
             octokit,

src/services/github.ts

@@ -23,6 +23,15 @@ export const hasDixChanges = (diff: string | undefined): boolean => {
   return baseMatch[1].trim() !== prMatch[1].trim();
 };
 
+// Detect if dix output includes any package section content
+export const hasPackageChanges = (diff: string | undefined): boolean => {
+  if (!diff || diff.trim() === "") return false;
+
+  const lines = diff.split(/\r?\n/);
+
+  return lines.length > 5;
+};
+
 // Git utilities
 export { sanitizeBranchName } from "./git.js";