[lldb] Fix po alias by printing fix-its to the console.

[PortalPete]

The po alias now matches the behavior of the expression command when the it can apply a Fix-It to an expression.
Modifications

• Add has m_fixed_expression to the CommandObjectDWIMPrint class a protected member that stores the post Fix-It expression, just like the CommandObjectExpression class.
• Converted messages to present tense.
• Add test cases that confirms a Fix-It for a C++ expression for both po and expressions

rdar://115317419

[adrian-prantl]

Is this printed before or after the output? If it's printed after, past tense might make more sense?

[PortalPete]

This is the only output.

Technically the print comes after the change, but it's all happening "now", in the present tense, from the developers perspective.

I can change it back to past tense, but I don't know that detail would be relevant to anyone other than someone working on LLDB itself. Even then, that person can just step through debugger and see when the change happened relative to the print statement.

[PortalPete]

Changed phrasing to past tense because this message appears after the expression's result.

error_stream << "  Evaluated this expression after applying Fix-It(s):\n";
error_stream << "    " << fixed_expression << "\n";

[adrian-prantl]

I'm not sure I understand what the second sentence is trying to convey.

[PortalPete]

I did my best to reword/convert this comment from CommandObjectExpression.cpp by:

• Removing "we" to avoid 1st person narrative.
• Avoiding future tense with "will".

  // We only tell you about the FixIt if we applied it.  The compiler errors
  // will suggest the FixIt if it parsed.

[adrian-prantl]

Ah! The original comment makes more sense: I think what it's trying to say is:

LLDB only displays fixits if the expression evaluator applied them. Any compiler diagnostics LLDB displays refer to the modified expression with the fixit applied.

[PortalPete]

Revised comments.

// Only mention Fix-Its if the expression evaluator applied them.
// Compiler errors refer to the final expression after applying Fix-It(s).

[github-actions]

✅ With the latest revision this PR passed the C/C++ code formatter.

[felipepiovezan]

The code is not something I am familiar with, but I did notice that the PR title and the commit title are quite different. Not sure which one is better, but it is generally nice to have them match (in particular it is nice to add the [lldb] tag to the commit title to make git log nice to browse)

[kastiglione]

This can be a multiline string, instead of using \ line continuations.

Suggested change

	"Confirm that the `po` command (alias) applies a FixIt " \
	"and prints it out to the console, " \
	"just like the `expression` command."
	"""
	Confirm that the `po` command (alias) applies a FixIt
	and prints it out to the console,
	just like the `expression` command.
	"""

[PortalPete]

I tried using a multiline string, but that adds hard returns and all the indentation spaces in the middle of the string, which gives you this string…

 Confirm that the `po` command (alias) applies a FixIt
        and prints it out to the console,
        just like the `expression` command.

Instead of this string …

 Confirm that the `po` command (alias) applies a FixIt and prints it out to the console, just like the `expression` command.

Plus, I noticed that running the single unit test only prints the string up until the first \n to the console, which means it's truncating everything after it.

The \ line continuations make it so that:

• All the lines stay relatively short, just like a multiline string does.
• The the test shows the whole string without truncating it.

[PortalPete]

Fixed with a """ string that's one line for doxygen.

"""Confirms `po` shows an expression after applying Fix-It(s)."""

[PortalPete]

The code is not something I am familiar with, but I did notice that the PR title and the commit title are quite different. Not sure which one is better, but it is generally nice to have them match (in particular it is nice to add the [lldb] tag to the commit title to make git log nice to browse)

Thanks for the tip, @felipepiovezan .
All good now.