Add a hint to the console output if more tasks execute in parallel than being displayed

[sschuberth]

Expected Behavior

When executing a build from the command line, the console rows prefixed with > indicate the number of tasks being executed in parallel. If the number of rows does not correspond to the number of tasks being executed in parallel, a hint should be displayed to avoid confusion.

Current Behavior

The number of rows displayed is capped at rows / 2 for terminals where rows is known, or hard-coded to 4 if rows is unknown:

gradle/subprojects/logging/src/main/java/org/gradle/internal/logging/console/ConsoleLayoutCalculator.java

Lines 37 to 42 in 5ec3f67

	if (maximumAvailableLines == -1) {
	// Disallow work-in-progress to take up more than half of the console display
	// If the screen size is unknown, allow 4 lines
	int rows = consoleMetaData.getRows();
	maximumAvailableLines = rows == 0 ? 4 : rows / 2;
	}

This means one cannot generally conclude the number of tasks being run in parallel from the number of rows being displayed.

Context

The current behavior has caused irritations when profiling a build for a project on Windows vs. Linux on the same (dual-boot) PC: On Linux the number of >-console-rows was much larger than on Windows although the terminal had much more rows for display in both cases, which led to the (false) assumption that less parallelism was being used on Windows than on Linux.

It turned out that due to MinTTY being used as a terminal on Windows, and the limitation documented at gradle/native-platform#33, it was simply a display issue.

In any case, also if the number of rows in being capped due to the rows / 2 constraint, a hint should be displayed on the console that the number of tasks being executed in parallel might be larger than the number of rows displayed in the console.