[PATCH v4 12/13] qapi/docs: add rendering for INTRO sections

[John Snow <jsnow@redhat.com>]

Amend the qapidoc generator to handle and render INTRO sections.

The only real difference here from other sections is that we need to
dedent the text so it renders correctly. Members and Features are also
indented, but do not require a dedent() because they are always used
in tandem with an rST construct that forms the start of a new indented
block; there is coincidental harmony.

Plaintext sections, however, do not start their own block and thus
need to be dedented to prevent accidentally rendering them as a
blockquote or a syntax error.

This dedent transformation on the text does not reflow the text, so
source line information remains accurate, and the "blame" chain of
custody for sphinx rST parsing error messages continues to be correct
even through this transformation.

Signed-off-by: John Snow <jsnow@redhat.com>
---
 docs/sphinx/qapidoc.py | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/docs/sphinx/qapidoc.py b/docs/sphinx/qapidoc.py
index 16ad15fe94f..54a32e45f7e 100644
--- a/docs/sphinx/qapidoc.py
+++ b/docs/sphinx/qapidoc.py
@@ -35,6 +35,7 @@
 from pathlib import Path
 import re
 import sys
+import textwrap
 from typing import TYPE_CHECKING
 
 from docutils import nodes
@@ -150,8 +151,15 @@ def add_lines(
         self,
         content: str,
         info: QAPISourceInfo,
+        dedent: bool = False,
     ) -> None:
         lines = content.splitlines(True)
+
+        if dedent:
+            lines = textwrap.dedent(content).splitlines(True)
+        else:
+            lines = content.splitlines(True)
+
         for i, line in enumerate(lines):
             self.add_line_raw(line, info.fname, info.line + i)
 
@@ -223,13 +231,16 @@ def reformat_arobase(text: str) -> str:
 
     # Transmogrification helpers
 
-    def visit_paragraph(self, section: QAPIDoc.Section) -> None:
+    def visit_plaintext(self, section: QAPIDoc.Section) -> None:
         # Squelch empty paragraphs.
         if not section.text:
             return
 
+        # Intro sections, which are indented in QAPI source, need to
+        # be dedented to avoid accidental block quotes in ReST syntax.
+        dedent = bool(section.kind == QAPIDoc.Kind.INTRO)
         self.ensure_blank_line()
-        self.add_lines(section.text, section.info)
+        self.add_lines(section.text, section.info, dedent)
         self.ensure_blank_line()
 
     def visit_member(self, section: QAPIDoc.ArgSection) -> None:
@@ -373,7 +384,7 @@ def visit_sections(self, ent: QAPISchemaDefinition) -> None:
             section.text = self.reformat_arobase(section.text)
 
             if section.kind.name in ("PLAIN", "INTRO"):
-                self.visit_paragraph(section)
+                self.visit_plaintext(section)
             elif section.kind == QAPIDoc.Kind.MEMBER:
                 assert isinstance(section, QAPIDoc.ArgSection)
                 if section.name == "q_dummy":
-- 
2.54.0