Fix "help format" output

[jessicah]

Summary

Fix "help" command output format.
It should keep output to the same line until TerminalWidth is reached.

[jessicah]

Todd, Zachary,

Can you help review this change?

Thanks,
Jessica

[jessicah]

Add Jim and Greg per Zachary's suggestion.

Jessica

[jingham]

Yes, your version clearly has the test right. I was wondering why this didn't have a more dramatic ill-effect, but it turns out that this function is only used for printing argument help text, which it clearly messes up:

(lldb) help format
<format>
            --
            One
            of
            the
            format
            names
            (or
            one-character
            names)

I'm not sure why we need a separate function for printing argument output that does wrapping differently from command help, but that's a question for another day.

It doesn't look like there are any tests for this help output. But it should be possible to write a test for this. You can get what you need programmatically, e.g.:

>>> result = lldb.SBCommandReturnObject()
>>> lldb.debugger.GetCommandInterpreter().HandleCommand("help format", result)
1
>>> print result.GetOutput()
<format> -- One of the format names (or one-character names) that can be used to show a variable's value:
            "default"
            'B' or "boolean"
            'b' or "binary"
            'y' or "bytes"
            'Y' or "bytes with ASCII"

And you can get & set the terminal width of the debugger with the SBDebugger.{Get,Set}TerminalWidth, so you could make sure that the length of line 1 + length of first word on line 2 > terminal width. The only tricky bit would be picking the right command to use.

This is such an obvious fix it seems unkind to stall it for a test, but OTOH, if you could whip one up that would be great!

[jingham]

BTW, the second listing was after applying your patch, showing it clearly does the right thing...

[clayborg]

Add a test for this and this will be good to go.

[jessicah]

A test case was added.

packages/Python/lldbsuite/test/help/TestHelp.py

             'command alias --long-help "I am a very friendly alias" -- averyfriendlyalias help')
         self.expect("help averyfriendlyalias", matching=True,
                     substrs=['I am a very friendly alias'])
+    @no_debug_info_test
+    def test_help_format_output(self):
+        """Test that help output reaches TerminalWidth."""
+        self.runCmd(
+            'settings set term-width 108')
+        self.expect(
+            "help format",
+            matching=True,
+            substrs=['<format> -- One of the format names'])

source/Interpreter/CommandInterpreter.cpp

 
   while (!text.empty()) {
     if (text.front() == '\n' ||
-        (text.front() == ' ' && nextWordLength(text.ltrim(' ')) < chars_left)) {
+        (text.front() == ' ' && nextWordLength(text.ltrim(' ')) > chars_left)) {
       strm.EOL();
       strm.Indent();
       chars_left = max_columns - indent_size;