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Fixed the race condition: print dev mode ready message after WatchService registration #526

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Fixed the race condition: print dev mode ready message after WatchService registration #526

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15 changes: 13 additions & 2 deletions src/main/java/io/openliberty/tools/common/plugins/util/DevUtil.java
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Original file line number Diff line number Diff line change
Expand Up @@ -2548,8 +2548,8 @@ public void runHotkeyReaderThread(ThreadPoolExecutor executor) {
// it's available
inputUnavailable.wait(500);
}
printDevModeMessages(inputUnavailable.get(), firstStartup);
firstStartup = false;

@turkeylurkey turkeylurkey Aug 25, 2026

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Could you explain why we don't need to clear this boolean anymore? The comment says "If the thread is already running..." so it makes me wonder if firstStartup is always false by the time this is called.

@sajeerzeji sajeerzeji Aug 27, 2026

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The firstStartup is always false by the time runHotkeyReaderThread() is reached. watchFiles() sets firstStartup = false before entering the watch loop via initWatchLoop(). The only call site for runHotkeyReaderThread() in ci.common is inside TestJob.run(), which runs after the watch loop is active, so watchFiles() has always completed by then. The old code reset it here to cover the premature call from DevMojo/DevTask before watchFiles() ran. That premature call is the race condition we are removing, and without it the reset is no longer needed.

// firstStartup is false by the time this is called after initial startup.
printDevModeMessages(inputUnavailable.get(), false);
} catch (InterruptedException e) {
debug("Interrupted while waiting to determine whether input can be read", e);
} catch (PluginExecutionException pe) {
Expand Down Expand Up @@ -3177,6 +3177,17 @@ public void watchFiles(File outputDirectory, File testOutputDirectory, final Thr
}
}

if (firstStartup) {
synchronized (inputUnavailable) {
try {
printDevModeMessages(inputUnavailable.get(), true);
} catch (PluginExecutionException pe) {
error(pe.getMessage());
}
}
firstStartup = false;
}

initWatchLoop();

while (true) {
Expand Down
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