fix(compose): mount named volumes so data survives --force-recreate

Sources/MockerKit/Compose/ComposeOrchestrator.swift

@@ -81,6 +81,21 @@ public actor ComposeOrchestrator {
             }
         }
 
+        // Named volumes are bind-mounted from their backing directory, so both an
+        // unusable name and a missing external volume have to fail here — before any
+        // service starts — rather than as a raw runtime path error half-way through.
+        if !composeFile.volumes.isEmpty {
+            let existing = Set(await volumeManager.list().map(\.name))
+            for volume in composeFile.volumes.values {
+                let name = volume.runtimeName(projectName: projectName)
+                _ = try volumeManager.mountpoint(name)
+                guard !volume.external || existing.contains(name) else {
+                    throw MockerError.operationFailed(
+                        "volume \(name) declared as external, but could not be found")
+                }
+            }
+        }
+
         // Create networks
         for (fullName, driver) in Self.networksToCreate(composeFile: composeFile, projectName: projectName) {
             do {
@@ -523,7 +538,15 @@ public actor ComposeOrchestrator {
         // Parse port mappings
         let ports = try service.ports.map { try PortMapping.parse($0) }
 
-        let volumes = try Self.resolveVolumeMounts(service.volumes, projectDir: projectDir)
+        // Named volumes bind-mount their backing directory, exactly as Docker does
+        // internally, so the data survives container recreation.
+        let volumes = try Self.resolveVolumeMounts(
+            service.volumes,
+            projectDir: projectDir,
+            namedVolumeSources: composeFile.volumes.mapValues {
+                try volumeManager.mountpoint($0.runtimeName(projectName: projectName))
+            }
+        )
 
         let config = ContainerConfig(
             name: containerName,
@@ -563,32 +586,38 @@ public actor ComposeOrchestrator {
 
     /// Resolve volume spec strings from a compose service into `VolumeMount` values.
     ///
-    /// Bind-mount host paths (absolute or relative) are included; anonymous volumes
-    /// (container paths only) are included; named volumes (bare names without path
-    /// separators) are skipped — Apple's virtiofs doesn't support chown from within
-    /// containers, which breaks images like postgres that chown their data directory
-    /// on init.
+    /// Bind-mount host paths and anonymous volumes (container paths only) are
+    /// included as-is. A name declared in the file's top-level `volumes:` section is
+    /// bind-mounted from its backing directory (`namedVolumeSources`), which is what
+    /// keeps the data alive across `compose up --force-recreate`; an undeclared bare
+    /// name has no backing directory and is dropped.
     ///
     /// Relative paths (`./foo`, `../bar`, `data/dir`) are resolved to absolute paths
     /// against `projectDir` (the Compose `--project-directory`, i.e. the directory
     /// containing the compose file unless overridden). This matches Docker Compose
     /// behaviour, where bind-mount sources are anchored to the project directory
     /// rather than the process's current working directory.
-    static func resolveVolumeMounts(_ volSpecs: [String], projectDir: URL) throws -> [VolumeMount] {
+    static func resolveVolumeMounts(
+        _ volSpecs: [String],
+        projectDir: URL,
+        namedVolumeSources: [String: String]
+    ) throws -> [VolumeMount] {
         var volumes: [VolumeMount] = []
         for volSpec in volSpecs {
             var mount = try VolumeMount.parse(volSpec)
-            if mount.source.isEmpty {
-                volumes.append(mount)
-            } else if mount.source.hasPrefix("/") {
+            if mount.source.isEmpty || mount.source.hasPrefix("/") {
                 volumes.append(mount)
             } else if mount.source.hasPrefix("~") {
                 mount.source = (mount.source as NSString).expandingTildeInPath
                 volumes.append(mount)
             } else if mount.source.hasPrefix(".")
                       || mount.source.contains("/") {
+                // Relative bind mount, anchored to the project directory.
                 mount.source = projectDir.appendingPathComponent(mount.source).standardized.path
                 volumes.append(mount)
+            } else if let source = namedVolumeSources[mount.source] {
+                mount.source = source
+                volumes.append(mount)
             }
         }
         return volumes

Sources/MockerKit/Volume/VolumeManager.swift

@@ -28,14 +28,23 @@ public actor VolumeManager {
         }
     }
 
+    /// Backing directory holding a volume's data. Compose bind-mounts it so named
+    /// volumes survive container recreation.
+    public nonisolated func mountpoint(_ name: String) throws -> String {
+        try Self.validateName(name)
+        return "\(storagePath)/\(name)/_data"
+    }
+
     /// Reject names that would escape the volumes directory. Every volume path is
     /// built by interpolating the name, and a compose file can supply it verbatim
     /// (`volumes: {data: {name: ...}}`), so `../` must never get through.
     static func validateName(_ name: String) throws {
-        // Only path escape is rejected — anything else stays removable, including
-        // volumes created before this check existed.
+        // Path escape and `:` are rejected — the latter because the backing directory
+        // goes into a `-v source:destination` argument, where it would misparse.
+        // Anything else stays removable, including volumes created before this check.
         let valid = !name.isEmpty
             && !name.contains("/")
+            && !name.contains(":")
             && name != "."
             && name != ".."
         guard valid else {
@@ -45,12 +54,11 @@ public actor VolumeManager {
 
     /// Create a new volume.
     public func create(name: String, driver: String = "local", labels: [String: String] = [:]) throws -> VolumeInfo {
-        try Self.validateName(name)
         guard volumes[name] == nil else {
             throw MockerError.operationFailed("Volume \(name) already exists")
         }
 
-        let mountpoint = "\(config.volumesPath)/\(name)/_data"
+        let mountpoint = try mountpoint(name)
         let fm = FileManager.default
         if !fm.fileExists(atPath: mountpoint) {
             try fm.createDirectory(atPath: mountpoint, withIntermediateDirectories: true)

Tests/MockerKitTests/ComposeOrchestratorTests.swift

@@ -161,7 +161,7 @@ struct ComposeOrchestratorTests {
 
     @Test("Absolute bind mount included as-is")
     func resolveAbsoluteBindMount() throws {
-        let mounts = try ComposeOrchestrator.resolveVolumeMounts(["/host/data:/container/data"], projectDir: Self.cwd)
+        let mounts = try Self.resolve(["/host/data:/container/data"])
         #expect(mounts.count == 1)
         #expect(mounts[0].source == "/host/data")
         #expect(mounts[0].destination == "/container/data")
@@ -176,47 +176,56 @@ struct ComposeOrchestratorTests {
         ]
     )
     func resolveRelativeStyleMounts(spec: String, suffix: String, destination: String) throws {
-        let mounts = try ComposeOrchestrator.resolveVolumeMounts([spec], projectDir: Self.cwd)
+        let mounts = try Self.resolve([spec])
         #expect(mounts.count == 1)
         #expect(mounts[0].source.hasPrefix("/"))
         #expect(mounts[0].source.hasSuffix(suffix))
         #expect(mounts[0].destination == destination)
     }
 
-    @Test("Named volume skipped")
-    func skipNamedVolume() throws {
-        let mounts = try ComposeOrchestrator.resolveVolumeMounts(["mydata:/container/data"], projectDir: Self.cwd)
+    @Test("Declared named volume resolved to its backing directory")
+    func resolveDeclaredNamedVolume() throws {
+        let mounts = try Self.resolve(["mydata:/container/data"], named: ["mydata": "/volumes/proj-mydata/_data"])
+        #expect(mounts.count == 1)
+        #expect(mounts[0].source == "/volumes/proj-mydata/_data")
+        #expect(mounts[0].destination == "/container/data")
+    }
+
+    @Test("Undeclared bare name is dropped")
+    func dropUndeclaredName() throws {
+        let mounts = try Self.resolve(["mydata:/container/data"])
         #expect(mounts.isEmpty)
     }
 
     @Test("Anonymous volume included")
     func includeAnonymousVolume() throws {
-        let mounts = try ComposeOrchestrator.resolveVolumeMounts(["/container/data"], projectDir: Self.cwd)
+        let mounts = try Self.resolve(["/container/data"])
         #expect(mounts.count == 1)
         #expect(mounts[0].source == "")
         #expect(mounts[0].destination == "/container/data")
     }
 
     @Test("Mix of bind mounts, named volumes, and anonymous volumes")
     func resolveMixedVolumes() throws {
-        let mounts = try ComposeOrchestrator.resolveVolumeMounts([
+        let mounts = try Self.resolve([
             "/abs/path:/app/data",
             "./relative:/app/rel",
             "namedvol:/app/named",
             "/app/anon",
             "sub/dir:/app/sub",
-        ], projectDir: Self.cwd)
-        #expect(mounts.count == 4)  // namedvol skipped
+        ], named: ["namedvol": "/volumes/proj-namedvol/_data"])
+        #expect(mounts.count == 5)
         let sources = mounts.map(\.source)
         #expect(sources.contains("/abs/path"))
+        #expect(sources.contains("/volumes/proj-namedvol/_data"))
         #expect(sources.contains(""))  // anonymous
         #expect(sources.contains(where: { $0.hasSuffix("/relative") }))
         #expect(sources.contains(where: { $0.hasSuffix("sub/dir") }))
     }
 
     @Test("Read-only relative bind mount preserves ro flag")
     func resolveRelativeReadOnly() throws {
-        let mounts = try ComposeOrchestrator.resolveVolumeMounts(["./data:/container/data:ro"], projectDir: Self.cwd)
+        let mounts = try Self.resolve(["./data:/container/data:ro"])
         #expect(mounts.count == 1)
         #expect(mounts[0].readOnly == true)
         #expect(mounts[0].destination == "/container/data")
@@ -225,13 +234,26 @@ struct ComposeOrchestratorTests {
 
     @Test("Home-relative path resolved")
     func resolveHomeRelativePath() throws {
-        let mounts = try ComposeOrchestrator.resolveVolumeMounts(["~/data:/container/data"], projectDir: Self.cwd)
+        let mounts = try Self.resolve(["~/data:/container/data"])
         #expect(mounts.count == 1)
         #expect(mounts[0].source.hasPrefix("/"))
         #expect(mounts[0].source.contains("data"))
         #expect(mounts[0].destination == "/container/data")
     }
 
+    /// Resolve specs against the test project directory, with named volumes already
+    /// mapped to their backing directories.
+    private static func resolve(
+        _ specs: [String],
+        named: [String: String] = [:]
+    ) throws -> [VolumeMount] {
+        try ComposeOrchestrator.resolveVolumeMounts(
+            specs,
+            projectDir: Self.cwd,
+            namedVolumeSources: named
+        )
+    }
+
     // MARK: - reconcileDecision (issue #59)
 
     private func singleServiceFile() throws -> ComposeFile {
@@ -488,7 +510,8 @@ struct ComposeOrchestratorTests {
         let projectDir = URL(fileURLWithPath: "/tmp/mocker-issue-60-project")
         let mounts = try ComposeOrchestrator.resolveVolumeMounts(
             ["./data:/container/data"],
-            projectDir: projectDir
+            projectDir: projectDir,
+            namedVolumeSources: [:]
         )
         #expect(mounts.count == 1)
         #expect(mounts[0].source == "/tmp/mocker-issue-60-project/data")
@@ -500,7 +523,8 @@ struct ComposeOrchestratorTests {
         let projectDir = URL(fileURLWithPath: "/tmp/mocker-issue-60-project/nested")
         let mounts = try ComposeOrchestrator.resolveVolumeMounts(
             ["../shared:/container/shared"],
-            projectDir: projectDir
+            projectDir: projectDir,
+            namedVolumeSources: [:]
         )
         #expect(mounts.count == 1)
         #expect(mounts[0].source == "/tmp/mocker-issue-60-project/shared")

Tests/MockerKitTests/ComposeVolumeLifecycleTests.swift

@@ -94,7 +94,7 @@ struct ComposeVolumeLifecycleTests {
     }
 
     @Test("Volume names that would escape the volumes directory are rejected", arguments: [
-        "../etc", "a/b", "..", ".", "",
+        "../etc", "a/b", "..", ".", "", "host:path",
     ])
     func rejectsEscapingVolumeNames(name: String) {
         #expect(throws: MockerError.self) {