Rework mount command string generation

src/spec-node/dockerfileUtils.ts

@@ -4,6 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 
 import * as semver from 'semver';
+import { Mount } from '../spec-configuration/containerFeaturesConfiguration';
 
 export { getConfigFilePath, getDockerfilePath, isDockerFileConfig, resolveConfigFilePath } from '../spec-configuration/configuration';
 export { uriToFsPath, parentURI } from '../spec-configuration/configurationCommonUtils';
@@ -270,3 +271,24 @@ export function supportsBuildContexts(dockerfile: Dockerfile) {
 	}
 	return semver.intersects(numVersion, '>=1.4');
 }
+
+/**
+ * Process the mount command arguments and return the command string 
+ * @param mount 
+ * @returns command string 
+ */
+export function generateMountCommand(mount: Mount | string): string[] {
+	const command: string = '--mount';
+
+	if (typeof mount === 'string') {
+		return [command, mount];
+	}
+
+	const type: string = `type=${mount.type},`;
+	const source: string = mount.source ? `src=${mount.source},` : '';
+	const destination: string = `dst=${mount.target}`;
+
+	const args: string = `${type}${source}${destination}`;
+
+	return [command, args];
+}

src/spec-node/singleContainer.ts

@@ -12,7 +12,7 @@ import { DevContainerConfig, DevContainerFromDockerfileConfig, DevContainerFromI
 import { LogLevel, Log, makeLog } from '../spec-utils/log';
 import { extendImage, getExtendImageBuildInfo, updateRemoteUserUID } from './containerFeatures';
 import { getDevcontainerMetadata, getImageBuildInfoFromDockerfile, getImageMetadataFromContainer, ImageMetadataEntry, lifecycleCommandOriginMapFromMetadata, mergeConfiguration, MergedDevContainerConfig } from './imageMetadata';
-import { ensureDockerfileHasFinalStageName } from './dockerfileUtils';
+import { ensureDockerfileHasFinalStageName, generateMountCommand } from './dockerfileUtils';
 
 export const hostFolderLabel = 'devcontainer.local_folder'; // used to label containers created from a workspace/folder
 export const configFileLabel = 'devcontainer.config_file';
@@ -360,7 +360,7 @@ export async function spawnDevContainer(params: DockerResolverParameters, config
 		...[
 			...mergedConfig.mounts || [],
 			...params.additionalMounts,
-		].map(m => ['--mount', typeof m === 'string' ? m : `type=${m.type},src=${m.source},dst=${m.target}`])
+		].map(m => generateMountCommand(m))
 	);
 
 	const customEntrypoints = mergedConfig.entrypoints || [];

src/test/configs/image-with-mounts/.devcontainer/devcontainer.json

@@ -0,0 +1,9 @@
+{
+	"image": "mcr.microsoft.com/devcontainers/base:latest",
+	"mounts": [
+        {
+            "target": "/home/vscode/.vscode-server",
+            "type": "volume",
+        }
+    ]
+}

src/test/imageMetadata.test.ts

@@ -202,6 +202,21 @@ describe('Image Metadata', function () {
 					await shellExec(`docker rm -f ${response.containerId}`);
 				});
 			});
+
+			['image-with-mounts'].forEach(testFolderName => {
+				it('docker volume should not be named undefined if the src argument is omitted in mount command', async () => {
+					const imageTestFolder = `${__dirname}/configs/${testFolderName}`;
+					const cliResult = await shellExec(`${cli} up --workspace-folder ${imageTestFolder}`);
+					const response = JSON.parse(cliResult.stdout);
+					assert.strictEqual(response.outcome, 'success');
+					const details = JSON.parse((await shellExec(`docker inspect ${response.containerId}`)).stdout)[0] as ContainerDetails;
+					const targetMount = details.Mounts.find(mount => mount.Destination === '/home/vscode/.vscode-server');
+
+					assert.notEqual(targetMount?.Name?.toLowerCase(), 'undefined');
+
+					await shellExec(`docker rm -f ${response.containerId}`);
+				});
+			});
 		});
 	});