Re: [PATCH 04/13] qapi/parser: preserve indentation in QAPIDoc sections

[Markus Armbruster <armbru@redhat.com>]

John Snow <jsnow@redhat.com> writes:

> Change get_doc_indented() to preserve indentation on all subsequent text
> lines, and create a compatibility dedent() function for qapidoc.py to
> remove that indentation. This is being done for the benefit of a new

Suggest "remove indentation the same way get_doc_indented() did."

> qapidoc generator which requires that indentation in argument and
> features sections are preserved.
>
> Prior to this patch, a section like this:
>
> ```
> @name: lorem ipsum
>    dolor sit amet
>      consectetur adipiscing elit
> ```
>
> would have its body text be parsed as:

Suggest "parsed into".

> (first and final newline only for presentation)
>
> ```
> lorem ipsum
> dolor sit amet
>   consectetur adipiscing elit
> ```
>
> We want to preserve the indentation for even the first body line so that
> the entire block can be parsed directly as rST. This patch would now
> parse that segment as:

If you change "parsed as" to "parsed into" above, then do it here, too.

>
> ```
> lorem ipsum
>    dolor sit amet
>      consectetur adipiscing elit
> ```
>
> This is helpful for formatting arguments and features as field lists in
> rST, where the new generator will format this information as:
>
> ```
> :arg type name: lorem ipsum
>    dolor sit amet
>      consectetur apidiscing elit
> ```
>
> ...and can be formed by the simple concatenation of the field list
> construct and the body text. The indents help preserve the continuation
> of a block-level element, and further allow the use of additional rST
> block-level constructs such as code blocks, lists, and other such
> markup. Avoiding reflowing the text conditionally also helps preserve
> source line context for better rST error reporting from sphinx through
> generated source, too.

What do you mean by "reflowing"?

> This understandably breaks the existing qapidoc.py; so a new function is
> added there to dedent the text for compatibility. Once the new generator
> is merged, this function will not be needed any longer and can be
> dropped.
>
> I verified this patch changes absolutely nothing by comparing the
> md5sums of the QMP ref html pages both before and after the change, so
> it's certified inert. QAPI test output has been updated to reflect the
> new strategy of preserving indents for rST.

I think the remainder is unnecessary detail.  Drop?

> before:
>
> 69cde3d6f18b0f324badbb447d4381ce  manual_before/interop/qemu-ga-ref.html
> 446e9381833def2adc779f1b90f2215f  manual_before/interop/qemu-qmp-ref.html
> df0ad6c26cb4c28b85d663fe44609c12  manual_before/interop/qemu-storage-daemon-qmp-ref.html
>
> after:
>
> 69cde3d6f18b0f324badbb447d4381ce  manual/interop/qemu-ga-ref.html
> 446e9381833def2adc779f1b90f2215f  manual/interop/qemu-qmp-ref.html
> df0ad6c26cb4c28b85d663fe44609c12  manual/interop/qemu-storage-daemon-qmp-ref.html
>
> Signed-off-by: John Snow <jsnow@redhat.com>
> ---
>  docs/sphinx/qapidoc.py         | 29 ++++++++++++++++++++++++-----
>  scripts/qapi/parser.py         |  5 +++--
>  tests/qapi-schema/doc-good.out | 32 ++++++++++++++++----------------
>  3 files changed, 43 insertions(+), 23 deletions(-)
>
> diff --git a/docs/sphinx/qapidoc.py b/docs/sphinx/qapidoc.py
> index e675966defa..f2f2005dd5f 100644
> --- a/docs/sphinx/qapidoc.py
> +++ b/docs/sphinx/qapidoc.py
> @@ -26,6 +26,7 @@
>  
>  import os
>  import re
> +import textwrap
>  
>  from docutils import nodes
>  from docutils.parsers.rst import Directive, directives
> @@ -53,6 +54,21 @@
>  __version__ = "1.0"
>  
>  
> +def dedent(text: str) -> str:
> +    # Temporary: In service of the new QAPI Sphinx domain, the QAPI doc
> +    # parser now preserves indents in args/members/features text.
> +    # QAPIDoc does not handle this well, so undo that change here.

A comment should explain how things are.  This one explains how things
have changed.  Suggest:

       # Adjust indentation to make description text parse as paragraph.

If we planned to keep this, we might want to explain in more detail, as
I did in review of v1.  But we don't.

> +
> +    lines = text.splitlines(True)
> +    if re.match(r"\s+", lines[0]):
> +        # First line is indented; description started on the line after
> +        # the name. dedent the whole block.
> +        return textwrap.dedent(text)
> +
> +    # Descr started on same line. Dedent line 2+.
> +    return lines[0] + textwrap.dedent("".join(lines[1:]))
> +
> +
>  # Disable black auto-formatter until re-enabled:
>  # fmt: off
>  
> @@ -176,7 +192,7 @@ def _nodes_for_members(self, doc, what, base=None, branches=None):
>              term = self._nodes_for_one_member(section.member)
>              # TODO drop fallbacks when undocumented members are outlawed
>              if section.text:
> -                defn = section.text
> +                defn = dedent(section.text)
>              else:
>                  defn = [nodes.Text('Not documented')]
>  
> @@ -214,7 +230,7 @@ def _nodes_for_enum_values(self, doc):
>                  termtext.extend(self._nodes_for_ifcond(section.member.ifcond))
>              # TODO drop fallbacks when undocumented members are outlawed
>              if section.text:
> -                defn = section.text
> +                defn = dedent(section.text)
>              else:
>                  defn = [nodes.Text('Not documented')]
>  
> @@ -249,7 +265,7 @@ def _nodes_for_features(self, doc):
>          dlnode = nodes.definition_list()
>          for section in doc.features.values():
>              dlnode += self._make_dlitem(
> -                [nodes.literal('', section.member.name)], section.text)
> +                [nodes.literal('', section.member.name)], dedent(section.text))
>              seen_item = True
>  
>          if not seen_item:
> @@ -272,9 +288,12 @@ def _nodes_for_sections(self, doc):
>                  continue
>              snode = self._make_section(section.tag)
>              if section.tag and section.tag.startswith('Example'):
> -                snode += self._nodes_for_example(section.text)
> +                snode += self._nodes_for_example(dedent(section.text))
>              else:
> -                self._parse_text_into_node(section.text, snode)
> +                self._parse_text_into_node(
> +                    dedent(section.text) if section.tag else section.text,
> +                    snode,
> +                )
>              nodelist.append(snode)
>          return nodelist
>  
> diff --git a/scripts/qapi/parser.py b/scripts/qapi/parser.py
> index 7b13a583ac1..43167ef0ab3 100644
> --- a/scripts/qapi/parser.py
> +++ b/scripts/qapi/parser.py
> @@ -437,6 +437,7 @@ def _match_at_name_colon(string: str) -> Optional[Match[str]]:
>          return re.match(r'@([^:]*): *', string)
>  
>      def get_doc_indented(self, doc: 'QAPIDoc') -> Optional[str]:
> +        """get_doc_indented preserves indentation for later rST parsing."""

A proper function comment explains what the function does.  This one
merely points out one minor aspect.  Easy fix: delete it.  Alternative
fix: write a proper function comment.

>          self.accept(False)
>          line = self.get_doc_line()
>          while line == '':

[...]

Just commit message and doc nitpicks, so
Reviewed-by: Markus Armbruster <armbru@redhat.com>