Add real-time verbose command streaming via stderr

src/run.ts

@@ -29,12 +29,23 @@ type RunOptions = {
 }
 
 const SENTINEL_PREFIX = "__SHOUT_SENTINEL_"
+const VERBOSE_MARKER = "__SHOUT_CMD_"
 
-function buildScript(commands: Command[], sentinel: string): string {
-  const lines: string[] = ["exec 2>&1"]
+function buildScript(commands: Command[], sentinel: string, verbose: boolean): string {
+  const lines: string[] = []
+
+  if (verbose) {
+    // Save original stderr to fd 3 before merging stderr into stdout
+    lines.push("exec 3>&2 2>&1")
+  } else {
+    lines.push("exec 2>&1")
+  }
 
   for (let i = 0; i < commands.length; i++) {
     const cmd = commands[i]!
+    if (verbose) {
+      lines.push(`printf '${VERBOSE_MARKER}${i}\\n' >&3`)
+    }
     lines.push(cmd.command)
     // Sentinel: printf to avoid echo interpretation issues
     // Format: __SHOUT_SENTINEL_<exitcode>_<index>__
@@ -111,6 +122,36 @@ function escapeRegex(s: string): string {
   return s.replace(/[.*+?^${}()|[\]\\]/g, "\\$&")
 }
 
+function streamVerboseMarkers(
+  stderr: ReadableStream<Uint8Array>,
+  commands: Command[],
+  onCommand: (cmd: Command) => void,
+): void {
+  const reader = stderr.getReader()
+  const decoder = new TextDecoder()
+  let buffer = ""
+
+  const pump = (): void => {
+    reader.read().then(({ done, value }) => {
+      if (done) return
+      if (value) buffer += decoder.decode(value, { stream: true })
+      let nlIdx: number
+      while ((nlIdx = buffer.indexOf("\n")) !== -1) {
+        const line = buffer.slice(0, nlIdx)
+        buffer = buffer.slice(nlIdx + 1)
+        if (line.startsWith(VERBOSE_MARKER)) {
+          const i = parseInt(line.slice(VERBOSE_MARKER.length), 10)
+          if (i >= 0 && i < commands.length) {
+            onCommand(commands[i]!)
+          }
+        }
+      }
+      pump()
+    }).catch(() => {})
+  }
+  pump()
+}
+
 export async function runFile(
   file: ShoutFile,
   options: RunOptions,
@@ -122,7 +163,8 @@ export async function runFile(
   }
 
   const sentinel = SENTINEL_PREFIX
-  const script = buildScript(file.commands, sentinel)
+  const verbose = options.verbose && !!options.onCommand
+  const script = buildScript(file.commands, sentinel, verbose)
 
   const env: Record<string, string> = options.cleanEnv
     ? {}
@@ -155,11 +197,19 @@ export async function runFile(
   })
 
   try {
+    if (verbose) {
+      // Stream stderr for verbose command markers before writing script
+      streamVerboseMarkers(proc.stderr, file.commands, options.onCommand!)
+    }
+
     proc.stdin.write(script)
     proc.stdin.end()
 
-    const stdout = await readWithTimeout(proc.stdout, options.timeout * file.commands.length)
-    const stderr = await readWithTimeout(proc.stderr, 1000).catch(() => "")
+    const totalTimeout = options.timeout * file.commands.length
+    const stdout = await readWithTimeout(proc.stdout, totalTimeout)
+    if (!verbose) {
+      await readWithTimeout(proc.stderr, 1000).catch(() => "")
+    }
 
     await proc.exited
 
@@ -169,16 +219,11 @@ export async function runFile(
       file.commands.length,
     )
 
-    const results: CommandResult[] = file.commands.map((cmd, i) => {
-      if (options.verbose && options.onCommand) {
-        options.onCommand(cmd)
-      }
-      return {
-        command: cmd,
-        actual: outputs[i] ?? [],
-        exitCode: exitCodes[i] ?? 1,
-      }
-    })
+    const results: CommandResult[] = file.commands.map((cmd, i) => ({
+      command: cmd,
+      actual: outputs[i] ?? [],
+      exitCode: exitCodes[i] ?? 1,
+    }))
 
     return { file, results, tmpDir }
   } catch (err) {