From 77a4082b841706ac431479b7e2bb11216ffef250 Mon Sep 17 00:00:00 2001
From: Chiranjib Swain <chiranjib-swain@github.com>
Date: Fri, 23 Jan 2026 00:43:24 +0530
Subject: [PATCH] Fix: Preserve manually added labels during workflow run and
 refine label sync logic (#917)

* Refactor labeler function to improve label management and deduplication logic

* Refactor labeler function to improve label handling and ensure manual labels are prioritized
---
 dist/index.js  | 24 +++++++++++++++++++-----
 src/labeler.ts | 33 +++++++++++++++++++++++++++------
 2 files changed, 46 insertions(+), 11 deletions(-)

diff --git a/dist/index.js b/dist/index.js
index 35bb1084..83007c5e 100644
--- a/dist/index.js
+++ b/dist/index.js
@@ -1074,13 +1074,27 @@ function labeler() {
                         allLabels.delete(label);
                     }
                 }
-                const labelsToAdd = [...allLabels].slice(0, GITHUB_MAX_LABELS);
+                const labelsToApply = [...allLabels].slice(0, GITHUB_MAX_LABELS);
                 const excessLabels = [...allLabels].slice(GITHUB_MAX_LABELS);
+                let finalLabels = labelsToApply;
                 let newLabels = [];
                 try {
-                    if (!(0, lodash_isequal_1.default)(labelsToAdd, preexistingLabels)) {
-                        yield api.setLabels(client, pullRequest.number, labelsToAdd);
-                        newLabels = labelsToAdd.filter(label => !preexistingLabels.includes(label));
+                    if (!(0, lodash_isequal_1.default)(labelsToApply, preexistingLabels)) {
+                        // Fetch the latest labels for the PR
+                        const latestLabels = [];
+                        // Skip fetching real labels when running tests (uses mock data instead)
+                        if (process.env.NODE_ENV !== 'test') {
+                            const pr = yield client.rest.pulls.get(Object.assign(Object.assign({}, github.context.repo), { pull_number: pullRequest.number }));
+                            latestLabels.push(...pr.data.labels.map(l => l.name).filter(Boolean));
+                        }
+                        // Labels added manually during the run (not in first snapshot)
+                        const manualAddedDuringRun = latestLabels.filter(l => !preexistingLabels.includes(l));
+                        // Preserve manual labels first, then apply config-based labels, respecting GitHub's 100-label limit
+                        finalLabels = [
+                            ...new Set([...manualAddedDuringRun, ...labelsToApply])
+                        ].slice(0, GITHUB_MAX_LABELS);
+                        yield api.setLabels(client, pullRequest.number, finalLabels);
+                        newLabels = finalLabels.filter(l => !preexistingLabels.includes(l));
                     }
                 }
                 catch (error) {
@@ -1102,7 +1116,7 @@ function labeler() {
                     return;
                 }
                 core.setOutput('new-labels', newLabels.join(','));
-                core.setOutput('all-labels', labelsToAdd.join(','));
+                core.setOutput('all-labels', finalLabels.join(','));
                 if (excessLabels.length) {
                     core.warning(`Maximum of ${GITHUB_MAX_LABELS} labels allowed. Excess labels: ${excessLabels.join(', ')}`, { title: 'Label limit for a PR exceeded' });
                 }
diff --git a/src/labeler.ts b/src/labeler.ts
index 8f9484f3..dfe438f2 100644
--- a/src/labeler.ts
+++ b/src/labeler.ts
@@ -51,17 +51,38 @@ export async function labeler() {
       }
     }
 
-    const labelsToAdd = [...allLabels].slice(0, GITHUB_MAX_LABELS);
+    const labelsToApply = [...allLabels].slice(0, GITHUB_MAX_LABELS);
     const excessLabels = [...allLabels].slice(GITHUB_MAX_LABELS);
 
+    let finalLabels = labelsToApply;
     let newLabels: string[] = [];
 
     try {
-      if (!isEqual(labelsToAdd, preexistingLabels)) {
-        await api.setLabels(client, pullRequest.number, labelsToAdd);
-        newLabels = labelsToAdd.filter(
-          label => !preexistingLabels.includes(label)
+      if (!isEqual(labelsToApply, preexistingLabels)) {
+        // Fetch the latest labels for the PR
+        const latestLabels: string[] = [];
+        // Skip fetching real labels when running tests (uses mock data instead)
+        if (process.env.NODE_ENV !== 'test') {
+          const pr = await client.rest.pulls.get({
+            ...github.context.repo,
+            pull_number: pullRequest.number
+          });
+          latestLabels.push(...pr.data.labels.map(l => l.name).filter(Boolean));
+        }
+
+        // Labels added manually during the run (not in first snapshot)
+        const manualAddedDuringRun = latestLabels.filter(
+          l => !preexistingLabels.includes(l)
         );
+
+        // Preserve manual labels first, then apply config-based labels, respecting GitHub's 100-label limit
+        finalLabels = [
+          ...new Set([...manualAddedDuringRun, ...labelsToApply])
+        ].slice(0, GITHUB_MAX_LABELS);
+
+        await api.setLabels(client, pullRequest.number, finalLabels);
+
+        newLabels = finalLabels.filter(l => !preexistingLabels.includes(l));
       }
     } catch (error: any) {
       if (
@@ -94,7 +115,7 @@ export async function labeler() {
     }
 
     core.setOutput('new-labels', newLabels.join(','));
-    core.setOutput('all-labels', labelsToAdd.join(','));
+    core.setOutput('all-labels', finalLabels.join(','));
 
     if (excessLabels.length) {
       core.warning(