Retry a launch that came up and then said nothing

The same interop launch flake that produced exit 127 with an empty log has a
second face: a non-zero exit after the engine banner and not one line more.
test_fleet_growth went that way once in six full-suite runs and passed alone
every time.

The line between a flake and a failure is output, not the exit code and not
the banner - every test says something before it stops, its own FAIL
verdict, a SCRIPT ERROR, an engine complaint. A log holding nothing but the
banner is a run that did not happen, so it is retried and, if it stays
silent, reported as NOSTART rather than as a test that failed. A
deterministic silent crash still fails all three attempts.

The check reads grep's output rather than its exit status: `grep -q -v` does
not agree across implementations - ugrep, which is what `grep` resolves to
on the WSL box, reports success for an empty file and failure for a file
full of matching lines.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

tests/_run_inside.sh

@@ -22,16 +22,35 @@ VERBOSE="$1"; shift
 # complete in seconds, even on a busy phone, so make that failure explicit
 # rather than making the suite look hung. Override for deliberate long runs.
 TEST_TIMEOUT_SECONDS="${TEST_TIMEOUT_SECONDS:-120}"
-# How many times to start a test whose process never came up at all. Under
-# WSL the Godot binary is a Windows executable started across the interop
-# boundary, and with six of them going at once that start occasionally just
-# fails - exit 127, an empty log, no engine banner, nothing run. It looked
-# exactly like a test failure while being a property of the launch, and it
-# moved from test to test between runs. A test that genuinely fails always
-# gets far enough to print the banner, so the two are easy to tell apart and
-# only the launch is worth retrying.
+# How many times to start a test whose process never got as far as saying
+# anything. Under WSL the Godot binary is a Windows executable started across
+# the interop boundary, and with six of them going at once that start
+# occasionally just fails. It has been seen two ways: exit 127 with a
+# completely empty log, and a non-zero exit after the engine banner and not
+# one line more. Both moved from test to test between runs and both passed
+# alone, so both are properties of the launch rather than of the test.
+#
+# The line that separates them from a real failure is OUTPUT, not the exit
+# code and not the banner: every test says something before it stops - its
+# own FAIL verdict, a SCRIPT ERROR, an engine complaint. A log holding
+# nothing but the banner is a run that did not happen. This can only ever
+# mask a fault that is both silent AND intermittent; a deterministic crash
+# still fails all LAUNCH_ATTEMPTS and is reported.
 LAUNCH_ATTEMPTS="${LAUNCH_ATTEMPTS:-3}"
 
+
+# Did the process produce any line of its own? The engine banner and blank
+# lines are what a bare launch prints by itself and do not count.
+#
+# Tests the OUTPUT rather than grep's exit status on purpose: `grep -q -v`
+# does not agree across greps - ugrep, which is what `grep` resolves to on
+# at least one machine this suite runs on, reports success for an empty file
+# and failure for a file full of matching lines. A non-empty result is the
+# same in every implementation.
+_said_anything() {
+  [[ -n "$(grep -v -e '^[[:space:]]*$' -e '^Godot Engine' "$1")" ]]
+}
+
 cd "$PROJECT_DIR" || exit 2
 
 tests=("$@")
@@ -71,9 +90,9 @@ run_one() {
     timeout "$TEST_TIMEOUT_SECONDS" "$GODOT_BIN" --headless --fixed-fps 60 \
       -s "res://tests/$name" >"$log" 2>&1
     rc=$?
-    # "Never started" is rc != 0 with no banner in the log. Anything that
-    # ran - passed, failed, crashed mid-way - printed the banner first.
-    if (( rc == 0 )) || grep -q "Godot Engine" "$log" \
+    # "Never started" is rc != 0 with a log that says nothing of its own.
+    # Anything that ran - passed, failed, crashed mid-way - said something.
+    if (( rc == 0 )) || _said_anything "$log" \
         || (( attempt >= LAUNCH_ATTEMPTS )); then
       break
     fi
@@ -106,7 +125,7 @@ run_one() {
     # indistinguishable from a hang.
     printf 'KILLED %4dms  %s (signal %d - out of memory? try JOBS=1)\n' \
       "$ms" "$name" "$(( rc - 128 ))" > "$outdir/$name.status"
-  elif (( rc != 0 )) && ! grep -q "Godot Engine" "$log"; then
+  elif (( rc != 0 )) && ! _said_anything "$log"; then
     printf 'NOSTART %3dms  %s (exit %d after %d attempts - the process never came up)\n' \
       "$ms" "$name" "$rc" "$attempt" > "$outdir/$name.status"
   else