[PATCH] doc: fix for out-of-tree builds of notmuch-emacs docs

[David Bremner]

The sphinx-doc include directive does not have the ability to include
files from the build tree, so we replace the include with reading the
files in conf.py. The non-trivial downside of this is that the emacs
docstrings are now defined for every rst source file. They are
namespaced with docstring::, so hopefully there will not be any
surprises. One thing that is noticable is a small (absolute) time
penalty in running sphinx-doc.
---
 doc/Makefile.local    |  2 +-
 doc/conf.py           | 19 +++++++++++++++----
 doc/notmuch-emacs.rst | 10 ----------
 3 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/doc/Makefile.local b/doc/Makefile.local
index b4e0c955..769438ed 100644
--- a/doc/Makefile.local
+++ b/doc/Makefile.local
@@ -4,7 +4,7 @@ dir := doc
 
 # You can set these variables from the command line.
 SPHINXOPTS    := -q
-SPHINXBUILD   = WITH_EMACS=${WITH_EMACS} sphinx-build
+SPHINXBUILD   = WITH_EMACS=${WITH_EMACS} RSTI_DIR=$(realpath emacs) sphinx-build
 DOCBUILDDIR      := $(dir)/_build
 
 # Internal variables.
diff --git a/doc/conf.py b/doc/conf.py
index fc9738ff..d8841d99 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -29,10 +29,21 @@ release = version
 # directories to ignore when looking for source files.
 exclude_patterns = ['_build']
 
-# If we don't have emacs (or the user configured --without-emacs),
-# don't build the notmuch-emacs docs, as they need emacs to generate
-# the docstring include files
-if os.environ.get('WITH_EMACS') != '1':
+if os.environ.get('WITH_EMACS') == '1':
+    # Hacky reimplementation of include to workaround limitations of
+    # sphinx-doc
+    accumulator='.. include:: /../emacs/rstdoc.rsti\n\n' # in the source tree
+    rsti_dir=os.environ.get('RSTI_DIR')
+    # the other files are from the build tree
+    for file in ['notmuch.rsti', 'notmuch-lib.rsti', 'notmuch-show.rsti', 'notmuch-tag.rsti']:
+        with open(rsti_dir+'/'+file) as f:
+            for line in f:
+                accumulator += line
+    rst_epilog=accumulator
+else:
+    # If we don't have emacs (or the user configured --without-emacs),
+    # don't build the notmuch-emacs docs, as they need emacs to generate
+    # the docstring include files
     exclude_patterns.append('notmuch-emacs.rst')
 
 # The name of the Pygments (syntax highlighting) style to use.
diff --git a/doc/notmuch-emacs.rst b/doc/notmuch-emacs.rst
index 1655e2f0..de47b726 100644
--- a/doc/notmuch-emacs.rst
+++ b/doc/notmuch-emacs.rst
@@ -377,13 +377,3 @@ suffix exist it will be read instead (just one of these, chosen in this
 order). Most often users create ``~/.emacs.d/notmuch-config.el`` and just
 work with it. If Emacs was invoked with the ``-q`` or ``--no-init-file``
 options, ``notmuch-init-file`` is not read.
-
-.. include:: ../emacs/rstdoc.rsti
-
-.. include:: ../emacs/notmuch.rsti
-
-.. include:: ../emacs/notmuch-lib.rsti
-
-.. include:: ../emacs/notmuch-show.rsti
-
-.. include:: ../emacs/notmuch-tag.rsti
-- 
2.26.2