Skip wasm build when dry run is disabled and --wasm is not specified. (flutter#174184)

This fixes an issue where the wasm build was still getting executed when
`--no-wasm-dry-run` was specified.

Also adds a test to verify the expected behavior.

Co-authored-by: Nate Biggs <[email protected]>

Author: biggs0125

packages/flutter_tools/lib/src/commands/build_web.dart

@@ -237,13 +237,14 @@ class BuildWebCommand extends BuildSubCommand {
           sourceMaps: sourceMaps,
           renderer: webRenderer,
         ),
-        WasmCompilerConfig(
-          optimizationLevel: optimizationLevel,
-          stripWasm: boolArg('strip-wasm'),
-          sourceMaps: sourceMaps,
-          minify: minifyWasm,
-          dryRun: boolArg('wasm-dry-run'),
-        ),
+        if (boolArg('wasm-dry-run'))
+          WasmCompilerConfig(
+            optimizationLevel: optimizationLevel,
+            stripWasm: boolArg('strip-wasm'),
+            sourceMaps: sourceMaps,
+            minify: minifyWasm,
+            dryRun: true,
+          ),
       ];
     }
 

packages/flutter_tools/test/commands.shard/hermetic/build_web_test.dart

@@ -439,6 +439,38 @@ void main() {
     },
   );
 
+  testUsingContext(
+    'Does not build wasm when wasm-dry-run is disabled',
+    () async {
+      final buildCommand = TestWebBuildCommand(fileSystem: fileSystem);
+      final CommandRunner<void> runner = createTestCommandRunner(buildCommand);
+      setupFileSystemForEndToEndTest(fileSystem);
+      await runner.run(<String>['build', 'web', '--no-pub', '--no-wasm-dry-run']);
+    },
+    overrides: <Type, Generator>{
+      Platform: () => fakePlatform,
+      FileSystem: () => fileSystem,
+      FeatureFlags: () => TestFeatureFlags(isWebEnabled: true),
+      ProcessManager: () => processManager,
+      BuildSystem: () =>
+          TestBuildSystem.all(BuildResult(success: true), (Target target, Environment environment) {
+            expect(target, isA<WebServiceWorker>());
+            final List<WebCompilerConfig> configs = (target as WebServiceWorker).compileConfigs;
+            expect(configs, hasLength(1));
+            final WebCompilerConfig jsConfig = configs[0];
+            expect(jsConfig.renderer, WebRendererMode.canvaskit);
+            expect(jsConfig.compileTarget, CompileTarget.js);
+            final List<String> jsOptions = jsConfig.toCommandOptions(BuildMode.release);
+            expect(jsOptions, <String>[
+              '--native-null-assertions',
+              '--no-source-maps',
+              '-O4',
+              '--minify',
+            ]);
+          }),
+    },
+  );
+
   testUsingContext(
     'Defaults to web renderer skwasm mode and minify for wasm when no option is specified',
     () async {