fix: respect output mode 'none' even when caching is disabled (#9670)

### Description

This is a fresh PR for #7900, which sat too long and got stale. I
accidentally closed the PR with no commits after force-pushing so I'm
opening this for simplicity's sake.

@aholland deserves all credit here for finding this issue and proposing
a fix.

### Testing Instructions

- Existing CI should catch me on regressions 🙏
- Added a test
- Did some manual testing. Things look to be doing what we want.

---------

Co-authored-by: Chris Olszewski <[email protected]>

crates/turborepo-lib/src/run/cache.rs

@@ -196,18 +196,15 @@ impl TaskCache {
     pub fn output_writer<W: Write>(&self, writer: W) -> Result<LogWriter<W>, Error> {
         let mut log_writer = LogWriter::default();
 
-        if self.caching_disabled || self.run_cache.writes_disabled {
-            log_writer.with_writer(writer);
-            return Ok(log_writer);
+        if !self.caching_disabled && !self.run_cache.writes_disabled {
+            log_writer.with_log_file(&self.log_file_path)?;
         }
 
-        log_writer.with_log_file(&self.log_file_path)?;
-
-        if !matches!(
-            self.task_output_logs,
-            OutputLogsMode::None | OutputLogsMode::HashOnly | OutputLogsMode::ErrorsOnly
-        ) {
-            log_writer.with_writer(writer);
+        match self.task_output_logs {
+            OutputLogsMode::None | OutputLogsMode::HashOnly | OutputLogsMode::ErrorsOnly => {}
+            OutputLogsMode::Full | OutputLogsMode::NewOnly => {
+                log_writer.with_writer(writer);
+            }
         }
 
         Ok(log_writer)

crates/turborepo-ui/src/logs.rs

@@ -58,9 +58,14 @@ impl<W: Write> Write for LogWriter<W> {
             (Some(log_file), None) => log_file.write(buf),
             (None, Some(prefixed_writer)) => prefixed_writer.write(buf),
             (None, None) => {
-                // Should this be an error or even a panic?
-                debug!("no log file or prefixed writer");
-                Ok(0)
+                debug!(
+                    "No log file or prefixed writer to write to. This should only happen when \
+                     both caching is disabled and output logs are set to none."
+                );
+
+                // Returning the buffer's length so callers don't think this is a failure to
+                // create the buffer
+                Ok(buf.len())
             }
         }
     }

turborepo-tests/integration/tests/run-logging/no-cache-and-no-output-logs.t

@@ -0,0 +1,13 @@
+Setup
+  $ . ${TESTDIR}/../../../helpers/setup_integration_test.sh run_logging
+
+  $ ${TURBO} run build --cache=local:,remote: --output-logs=none
+   WARNING  no caches are enabled
+  \xe2\x80\xa2 Packages in scope: app-a (esc)
+  \xe2\x80\xa2 Running build in 1 packages (esc)
+  \xe2\x80\xa2 Remote caching disabled (esc)
+
+   Tasks:    1 successful, 1 total
+  Cached:    0 cached, 1 total
+    Time:\s*[\.0-9]+m?s  (re)
+