feat(cache): default outputs to automatic tracking

Co-authored-by: GPT-5 Codex <codex@openai.com>

Author: wan9chi

CHANGELOG.md

@@ -3,6 +3,7 @@
 - **Added** Runner-aware tools can now call `ignoreInput(path)` to exclude non-semantic reads from auto-inferred task cache inputs.
 - **Added** Runner-aware tools can now call `ignoreOutput(path)` to exclude non-semantic writes from read/write overlap checks.
 - **Added** Cached tasks can opt into automatic output restoration with `output: [{ auto: true }]`.
+- **Changed** Cached tasks now automatically restore written output files when `output` is omitted; use `output: []` to disable output restoration.
 - **Changed** Tracked environment values in task cache fingerprints are now stored only as SHA-256 digests, and env-related cache miss details report names without values.
 - **Added** Runner-aware `getEnvs` match sets can now participate in task cache fingerprints, so changing, adding, or removing a matching env var invalidates the cache ([#450](https://github.com/voidzero-dev/vite-task/pull/450)).
 - **Added** Runner-aware `getEnvs` calls now return env values served by the runner for matching env glob patterns ([#449](https://github.com/voidzero-dev/vite-task/pull/449)).

crates/vite_task_bin/tests/e2e_snapshots/fixtures/input_cache_test/snapshots.toml

@@ -233,10 +233,10 @@ steps = [
 [[e2e]]
 name = "fspy_env___not_set_when_auto_inference_disabled"
 comment = """
-When auto-inference is disabled (explicit globs only), the task process should not see `FSPY` set.
+When both input and output auto-inference are disabled, the task process should not see `FSPY` set.
 """
 steps = [
-  # Run task without auto inference - should see (undefined)
+  # Run task without input or output auto inference - should see (undefined)
   ["vt", "run", "check-fspy-env-without-auto"],
 ]
 

crates/vite_task_bin/tests/e2e_snapshots/fixtures/input_cache_test/snapshots/fspy_env___not_set_when_auto_inference_disabled.md

@@ -1,6 +1,6 @@
 # fspy_env___not_set_when_auto_inference_disabled
 
-When auto-inference is disabled (explicit globs only), the task process should not see `FSPY` set.
+When both input and output auto-inference are disabled, the task process should not see `FSPY` set.
 
 ## `vt run check-fspy-env-without-auto`
 

crates/vite_task_bin/tests/e2e_snapshots/fixtures/input_cache_test/vite-task.json

@@ -62,6 +62,7 @@
     "check-fspy-env-without-auto": {
       "command": "vtt print-env FSPY",
       "input": ["src/**/*.ts"],
+      "output": [],
       "cache": true
     },
     "folder-input": {

crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/snapshots.toml

@@ -87,6 +87,35 @@ steps = [
   ], comment = "restored from the auto output archive" },
 ]
 
+[[e2e]]
+name = "default_auto_output_restores_written_files"
+comment = """
+Exercises the default output behavior. When `output` is omitted, the runner automatically tracks writes, archives the generated file, and restores it on cache hit.
+"""
+ignore = true
+steps = [
+  { argv = [
+    "vt",
+    "run",
+    "auto-output-default",
+  ], comment = "first run writes dist/default.txt and archives fspy-tracked outputs" },
+  { argv = [
+    "vtt",
+    "rm",
+    "dist/default.txt",
+  ], comment = "remove the output so restoration is observable" },
+  { argv = [
+    "vt",
+    "run",
+    "auto-output-default",
+  ], comment = "cache hit: default auto output is restored" },
+  { argv = [
+    "vtt",
+    "print-file",
+    "dist/default.txt",
+  ], comment = "restored from the default auto output archive" },
+]
+
 [[e2e]]
 name = "disable_cache_forces_reexecution"
 comment = """

crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/snapshots/default_auto_output_restores_written_files.md

@@ -0,0 +1,37 @@
+# default_auto_output_restores_written_files
+
+Exercises the default output behavior. When `output` is omitted, the runner automatically tracks writes, archives the generated file, and restores it on cache hit.
+
+## `vt run auto-output-default`
+
+first run writes dist/default.txt and archives fspy-tracked outputs
+
+```
+$ vtt write-file dist/default.txt ok
+```
+
+## `vtt rm dist/default.txt`
+
+remove the output so restoration is observable
+
+```
+```
+
+## `vt run auto-output-default`
+
+cache hit: default auto output is restored
+
+```
+$ vtt write-file dist/default.txt ok ◉ cache hit, replaying
+
+---
+vt run: cache hit.
+```
+
+## `vtt print-file dist/default.txt`
+
+restored from the default auto output archive
+
+```
+ok
+```

crates/vite_task_bin/tests/e2e_snapshots/fixtures/ipc_client_test/vite-task.json

@@ -15,6 +15,11 @@
       "output": [{ "auto": true }],
       "cache": true
     },
+    "auto-output-default": {
+      "command": "vtt write-file dist/default.txt ok",
+      "input": [],
+      "cache": true
+    },
     "disable-cache": {
       "command": "node scripts/disable_cache.mjs",
       "cache": true

crates/vite_task_graph/run-config.ts

@@ -57,9 +57,10 @@ untrackedEnv?: Array<string>,
  */
 input?: Array<string | GlobWithBase | AutoInput>, 
 /**
- * Output files to archive after a successful run and restore on cache hit.
+ * Output files to archive and restore on cache hit.
  *
- * - Omitted or `[]` (empty): no output archiving (default)
+ * - Omitted: automatically tracks which files the task writes
+ * - `[]` (empty): disables output restoration entirely
  * - Glob patterns (e.g. `"dist/**"`) select specific output files, relative to the package directory
  * - `{pattern: "...", base: "workspace" | "package"}` specifies a glob with an explicit base directory
  * - `{auto: true}` enables automatic output tracking

crates/vite_task_graph/src/config/mod.rs

@@ -198,8 +198,8 @@ impl ResolvedGlobConfig {
 
     /// Resolve from user output configuration, making glob patterns workspace-root-relative.
     ///
-    /// Unlike [`Self::from_user_config`], `None` and `Some([])` both produce an
-    /// empty config with `includes_auto = false` (no output archiving).
+    /// Unlike [`Self::from_user_config`], `None` defaults to automatic output
+    /// tracking while `Some([])` disables output archiving.
     ///
     /// # Errors
     ///
@@ -215,7 +215,7 @@ impl ResolvedGlobConfig {
         let mut includes_auto = false;
 
         let Some(entries) = user_outputs else {
-            return Ok(Self { includes_auto: false, positive_globs, negative_globs });
+            return Ok(Self::default_auto());
         };
 
         for entry in entries {

crates/vite_task_graph/src/config/user.rs

@@ -145,9 +145,10 @@ pub struct EnabledCacheConfig {
     #[cfg_attr(all(test, not(clippy)), ts(inline))]
     pub input: Option<UserInputsConfig>,
 
-    /// Output files to archive after a successful run and restore on cache hit.
+    /// Output files to archive and restore on cache hit.
     ///
-    /// - Omitted or `[]` (empty): no output archiving (default)
+    /// - Omitted: automatically tracks which files the task writes
+    /// - `[]` (empty): disables output restoration entirely
     /// - Glob patterns (e.g. `"dist/**"`) select specific output files, relative to the package directory
     /// - `{pattern: "...", base: "workspace" | "package"}` specifies a glob with an explicit base directory
     /// - `{auto: true}` enables automatic output tracking