fix: override action variables via --var cli flag

allow overriding action variables via --var cli flag. Previously, variables set
using the --var cli flag only had impact on the
project level variables.

core/src/garden.ts

@@ -1996,7 +1996,7 @@ export const resolveGardenParams = profileAsync(async function _resolveGardenPar
 })
 
 // Override variables, also allows to override nested variables using dot notation
-function overrideVariables(variables: DeepPrimitiveMap, overrideVariables: DeepPrimitiveMap): DeepPrimitiveMap {
+export function overrideVariables(variables: DeepPrimitiveMap, overrideVariables: DeepPrimitiveMap): DeepPrimitiveMap {
   let objNew = cloneDeep(variables)
   Object.keys(overrideVariables).forEach((key) => {
     if (objNew.hasOwnProperty(key)) {

core/src/graph/actions.ts

@@ -39,7 +39,7 @@ import type { GroupConfig } from "../config/group"
 import { ActionConfigContext } from "../config/template-contexts/actions"
 import { validateWithPath } from "../config/validation"
 import { ConfigurationError, InternalError, PluginError, ValidationError } from "../exceptions"
-import type { Garden } from "../garden"
+import { overrideVariables, type Garden } from "../garden"
 import type { Log } from "../logger/log-entry"
 import type { ActionTypeDefinition } from "../plugin/action-types"
 import { getActionTypeBases } from "../plugins"
@@ -299,12 +299,17 @@ export const actionFromConfig = profileAsync(async function actionFromConfig({
     config.internal.treeVersion ||
     (await garden.vcs.getTreeVersion({ log, projectName: garden.projectName, config, scanRoot }))
 
-  const variables = await mergeVariables({
+  let variables = await mergeVariables({
     basePath: config.internal.basePath,
     variables: config.variables,
     varfiles: config.varfiles,
   })
 
+  // override the variables if there's any matching variables in variable overrides
+  // passed via --var cli flag. variables passed via --var cli flag have highest precedence
+  const variableOverrides = garden.variableOverrides || {}
+  variables = overrideVariables(variables ?? {}, variableOverrides)
+
   const params: ActionWrapperParams<any> = {
     baseBuildDirectory: garden.buildStaging.buildDirPath,
     compatibleTypes,

core/test/unit/src/actions/action-configs-to-graph.ts

@@ -12,7 +12,7 @@ import { actionConfigsToGraph } from "../../../../src/graph/actions"
 import { ModuleGraph } from "../../../../src/graph/modules"
 import { Log } from "../../../../src/logger/log-entry"
 import { dumpYaml } from "../../../../src/util/serialization"
-import { expectError, makeTempGarden, TempDirectory, TestGarden } from "../../../helpers"
+import { createProjectConfig, expectError, makeTempGarden, TempDirectory, TestGarden } from "../../../helpers"
 import {
   DEFAULT_BUILD_TIMEOUT_SEC,
   DEFAULT_DEPLOY_TIMEOUT_SEC,
@@ -545,6 +545,71 @@ describe("actionConfigsToGraph", () => {
     expect(vars).to.eql({ foo: "FOO", bar: "BAR", baz: "baz" })
   })
 
+  it("correctly merges varfile with variables when some variables are overridden with --var cli flag", async () => {
+    const dummyGardenInstance = await makeTempGarden({
+      config: createProjectConfig({
+        name: "test",
+        environments: [{ name: "default", defaultNamespace: "foo", variables: {} }],
+      }),
+      variableOverrides: { "foo": "NEW_FOO", "nested.key1": "NEW_KEY_1_VALUE" },
+    })
+
+    let tmpDir = dummyGardenInstance.tmpDir
+    let garden = dummyGardenInstance.garden
+    let log = garden.log
+
+    try {
+      const varfilePath = join(tmpDir.path, "varfile.yml")
+      await dumpYaml(varfilePath, {
+        foo: "FOO",
+        bar: "BAR",
+        nested: {
+          key1: "SOME_VALUE",
+        },
+      })
+
+      const graph = await actionConfigsToGraph({
+        garden,
+        log,
+        groupConfigs: [],
+        configs: [
+          {
+            kind: "Build",
+            type: "test",
+            name: "foo",
+            timeout: DEFAULT_BUILD_TIMEOUT_SEC,
+            variables: {
+              foo: "foo",
+              baz: "baz",
+            },
+            varfiles: [varfilePath],
+            internal: {
+              basePath: tmpDir.path,
+            },
+            spec: {},
+          },
+        ],
+        moduleGraph: new ModuleGraph([], {}),
+        actionModes: {},
+        linkedSources: {},
+      })
+
+      const action = graph.getBuild("foo")
+      const vars = action["variables"]
+
+      expect(vars).to.eql({
+        foo: "NEW_FOO",
+        bar: "BAR",
+        baz: "baz",
+        nested: {
+          key1: "NEW_KEY_1_VALUE",
+        },
+      })
+    } finally {
+      await tmpDir.cleanup()
+    }
+  })
+
   it("sets sync mode correctly if explicitly set in actionModes", async () => {
     const graph = await actionConfigsToGraph({
       garden,