fix(logging): stop the no-config window dropping every log line

unitTests/utility/logging/fixtures/noConfigLogging.cjs

@@ -0,0 +1,15 @@
+'use strict';
+
+// The no-config logging window — install, and any host with no harperdb-config.yaml.
+// initLogSettings() picks that branch at module load, from the machine's own config resolution,
+// which is why this is a child: the caller spawns it with ROOTPATH at a directory holding no
+// config, and the branch is then taken on an installed machine and a bare one alike.
+
+const { warn } = require('#src/utility/logging/harper_logger');
+
+warn('no-config stream check');
+
+// stdioLogging() stashes its 'error' listener on the stream it guards, and the fallback branch
+// returns before the call at the end of initLogSettings().
+const guarded = (stream) => typeof stream.harperStdioErrorHandler === 'function';
+process.stdout.write(`stdout-guard=${guarded(process.stdout)} stderr-guard=${guarded(process.stderr)}\n`);

unitTests/utility/logging/harper_logger.test.js

@@ -1,7 +1,8 @@
 'use strict';
 
 const assert = require('node:assert');
-const { EventEmitter } = require('node:events');
+const { EventEmitter, once } = require('node:events');
+const { spawn } = require('node:child_process');
 const sinon = require('sinon');
 const chai = require('chai');
 const expect = chai.expect;
@@ -192,6 +193,40 @@ describe('Test harper_logger module', () => {
 			expect(log_file_path).to.eql(path.join(TEST_LOG_DIR, 'hdb.log'));
 		});
 
+		// The install window, and any host with no harperdb-config.yaml. `log_to_file` is false
+		// there, so the streams are the only sink left; createLogger() shadows the module-level
+		// `logToStdstreams` with its own option, and a call that omits it drops the line entirely
+		// rather than writing it anywhere (harper#2364, where the Windows gate caught it as a
+		// warning-cadence test counting 0 of 2).
+		it('writes to the std streams, guarded, when there is no config to read', async function () {
+			this.timeout(30000);
+			const noConfigRoot = fs.mkdtempSync(path.join(os.tmpdir(), 'harper-no-config-'));
+			afterThisTest.push(() => {
+				try {
+					fs.removeSync(noConfigRoot);
+				} catch {}
+			});
+
+			// A ROOTPATH naming a directory with no config reaches the fallback either way: with boot
+			// properties present the config read throws ENOENT, and without them initLogSettings()
+			// only swallows that failure when ROOTPATH *does* hold a config. LOGGING_LEVEL is pinned
+			// for the same reason — that branch reads it from the environment, and the fixture logs
+			// at the default threshold.
+			const child = spawn(process.execPath, [require.resolve('./fixtures/noConfigLogging.cjs')], {
+				stdio: ['ignore', 'pipe', 'pipe'],
+				env: { ...process.env, ROOTPATH: noConfigRoot, LOGGING_LEVEL: 'warn' },
+			});
+			let stdout = '';
+			let stderr = '';
+			child.stdout.on('data', (chunk) => (stdout += chunk));
+			child.stderr.on('data', (chunk) => (stderr += chunk));
+			const [code] = await once(child, 'close');
+
+			assert.equal(code, 0, `fixture exited ${code}: ${stderr}`);
+			assert.match(stderr, /no-config stream check/);
+			assert.match(stdout, /stdout-guard=true stderr-guard=true/);
+		});
+
 		it('Test that if error code is not ENOENT error is handled correctly', () => {
 			// This asserts the path where there is nothing to fall back to, so ROOTPATH has to be
 			// absent: initLogSettings() deliberately SWALLOWS a failure to read the boot properties

utility/logging/harper_logger.ts

@@ -545,10 +545,17 @@ export function initLogSettings(forceInit = false) {
 
 			logLevel = logLevel === undefined ? defaultLevel : logLevel;
 
-			mainLogger = createLogger({ level: logLevel });
+			// createLogger shadows the module-level `logToStdstreams` with this option, so omitting it
+			// drops every log written before a config exists rather than routing it to the streams.
+			mainLogger = createLogger({ level: logLevel, stdStreams: logToStdstreams });
 			// setup the external logger
 			externalLogger = mainLogger.forComponent('external');
 			externalLogger.tag = null; // don't tag by default
+			// The streams are this branch's only sink, so it needs the same EPIPE/EIO listeners the
+			// configured path installs below: `harper install | head -1` closes the reader, and the
+			// async error would otherwise land on a stream with none and take the install down. The
+			// guard's write override is inert here, because `log_to_file` is false.
+			stdioLogging();
 			return;
 		}