fix: correctly handle duplicate id checks in glob loader (#15064)

* fix: correctly handle duplicate id checks in glob loader

* Check if file exists to avoid race condition

* Fix test

Author: ascorbic

.changeset/bright-worlds-juggle.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes a bug that caused incorrect warnings of duplicate entries to be logged by the glob loader when editing a file

packages/astro/src/content/loaders/glob.ts

@@ -142,14 +142,20 @@ export function glob(globOptions: GlobOptions): Loader {
 					data,
 					filePath,
 				});
-				if (entryType.getRenderFunction) {
-					let render = renderFunctionByContentType.get(entryType);
 
-					if (store.has(id)) {
+				if (existingEntry && existingEntry.filePath && existingEntry.filePath !== relativePath) {
+					// Check the old file still exists - if not, this is likely a rename and
+					// the unlink event just hasn't been processed yet
+					const oldFilePath = new URL(existingEntry.filePath, config.root);
+					if (existsSync(oldFilePath)) {
 						logger.warn(
 							`Duplicate id "${id}" found in ${filePath}. Later items with the same id will overwrite earlier ones.`,
 						);
 					}
+				}
+
+				if (entryType.getRenderFunction) {
+					let render = renderFunctionByContentType.get(entryType);
 
 					if (!render) {
 						render = await entryType.getRenderFunction(config);

packages/astro/test/content-layer.test.js

@@ -99,7 +99,7 @@ describe('Content Layer', () => {
 		it('handles negative matches in glob() loader', async () => {
 			assert.ok(json.hasOwnProperty('probes'));
 			assert.ok(Array.isArray(json.probes));
-			assert.equal(json.probes.length, 5);
+			assert.equal(json.probes.length, 6);
 			assert.ok(
 				json.probes.every(({ id }) => !id.startsWith('voyager')),
 				'Voyager probes should not be included',
@@ -434,6 +434,12 @@ describe('Content Layer', () => {
 			);
 		});
 
+		it('warns about duplicate IDs in glob() loader', () => {
+			assert.ok(
+				logs.find((log) => log.level === 'warn' && log.message.includes('Duplicate id "cassini"')),
+			);
+		});
+
 		it("warns about missing files in glob() loader's path", async () => {
 			assert.ok(
 				logs.find((log) => log.level === 'warn' && log.message.includes('No files found matching')),
@@ -581,6 +587,41 @@ describe('Content Layer', () => {
 			await fixture.resetAllFiles();
 		});
 
+		it('does not warn about duplicate IDs when a file is edited', async () => {
+			logs.length = 0;
+
+			await fixture.editFile('/src/content/space/endeavour.md', (prev) => {
+				return prev.replace('learn about the', 'Learn about the');
+			});
+
+			await fixture.onNextDataStoreChange();
+
+			const duplicateWarning = logs.find((log) => log.message.includes('Duplicate id "endeavour"'));
+			assert.ok(!duplicateWarning, 'Should not warn about duplicate ID when editing same file');
+
+			await fixture.resetAllFiles();
+		});
+
+		it('does not warn about duplicate IDs when a file with a slug is renamed', async () => {
+			logs.length = 0;
+
+			// dawn.md has slug: dawn-mission - renaming should not cause duplicate warning
+			const oldPath = new URL('./data/space-probes/dawn.md', fixture.config.srcDir);
+			const newPath = new URL('./data/space-probes/dawn-renamed.md', fixture.config.srcDir);
+
+			await fs.rename(oldPath, newPath);
+			await fixture.onNextDataStoreChange();
+
+			try {
+				const duplicateWarning = logs.find((log) =>
+					log.message.includes('Duplicate id "dawn-mission"'),
+				);
+				assert.ok(!duplicateWarning, 'Should not warn about duplicate ID when renaming file');
+			} finally {
+				await fs.rename(newPath, oldPath);
+			}
+		});
+
 		it('returns an error if we render an undefined entry', async () => {
 			const res = await fixture.fetch('/missing');
 			const text = await res.text();

packages/astro/test/fixtures/content-layer/src/data/space-probes/cassini-2.md

@@ -0,0 +1,13 @@
+---
+slug: cassini
+name: Cassini Duplicate
+type: Space Probe
+launch_date: 1997-10-15
+status: Decommissioned
+destination: Saturn
+operator: NASA/ESA/ASI
+notable_discoveries:
+  - This is a duplicate entry for testing
+---
+
+This file has the same slug as cassini.md to test duplicate ID detection.

packages/astro/test/fixtures/content-layer/src/data/space-probes/dawn.md

@@ -0,0 +1,14 @@
+---
+slug: dawn-mission
+name: Dawn
+type: Space Probe
+launch_date: 2007-09-27
+status: Decommissioned
+destination: Asteroid Belt
+operator: NASA
+notable_discoveries:
+  - Ceres' bright spots
+  - Vesta's geological features
+---
+
+Dawn was a NASA space probe launched to study the asteroid belt objects Vesta and Ceres. It was the first spacecraft to orbit two extraterrestrial bodies and provided detailed data about the early solar system.