Bump minimal versions of refman dependencies.

Fixes #11936.

Co-authored-by: Jim Fehrle <jfehrle@sbcglobal.net>

5 files changed, 16 insertions, 9 deletions

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index f26804e120..fc0cdebcf0 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -18,7 +18,7 @@ stages:
 variables:
   # Format: $IMAGE-V$DATE [Cache is not used as of today but kept here
   # for reference]
-  CACHEKEY: "bionic_coq-V2020-05-06-V70"
+  CACHEKEY: "bionic_coq-V2020-05-18-V3"
   IMAGE: "$CI_REGISTRY_IMAGE:$CACHEKEY"
   # By default, jobs run in the base switch; override to select another switch
   OPAM_SWITCH: "base"
diff --git a/dev/ci/docker/bionic_coq/Dockerfile b/dev/ci/docker/bionic_coq/Dockerfile
index 9ee6496ee5..51a602303a 100644
--- a/dev/ci/docker/bionic_coq/Dockerfile
+++ b/dev/ci/docker/bionic_coq/Dockerfile
@@ -1,4 +1,4 @@
-# CACHEKEY: "bionic_coq-V2020-05-06-V70"
+# CACHEKEY: "bionic_coq-V2020-05-18-V3"
 # ^^ Update when modifying this file.
 
 FROM ubuntu:bionic
@@ -14,12 +14,13 @@ RUN apt-get update -qq && apt-get install --no-install-recommends -y -qq \
         # Dependencies of stdlib and sphinx doc
         texlive-latex-extra texlive-fonts-recommended texlive-xetex latexmk \
         xindy python3-pip python3-setuptools python3-pexpect python3-bs4 \
+        fonts-freefont-otf \
         # Dependencies of source-doc and coq-makefile
         texlive-science tipa
 
 # More dependencies of the sphinx doc
-RUN pip3 install sphinx==1.8.0 sphinx_rtd_theme==0.2.5b2 \
-                 antlr4-python3-runtime==4.7.1 sphinxcontrib-bibtex==0.4.0
+RUN pip3 install sphinx==2.3.1 sphinx_rtd_theme==0.4.3 \
+                 antlr4-python3-runtime==4.7.1 sphinxcontrib-bibtex==0.4.2
 
 # We need to install OPAM 2.0 manually for now.
 RUN wget https://github.com/ocaml/opam/releases/download/2.0.6/opam-2.0.6-x86_64-linux -O /usr/bin/opam && chmod 755 /usr/bin/opam
diff --git a/doc/README.md b/doc/README.md
index e749bcf5d1..8e1bc85c49 100644
--- a/doc/README.md
+++ b/doc/README.md
@@ -30,12 +30,12 @@ To produce the complete documentation in HTML, you will need Coq dependencies
 listed in [`INSTALL.md`](../INSTALL.md). Additionally, the Sphinx-based
 reference manual requires Python 3, and the following Python packages:
 
-  - sphinx >= 1.8.0
-  - sphinx_rtd_theme >= 0.2.5b2
+  - sphinx >= 2.3.1
+  - sphinx_rtd_theme >= 0.4.3
   - beautifulsoup4 >= 4.0.6
   - antlr4-python3-runtime >= 4.7.1
   - pexpect >= 4.2.1
-  - sphinxcontrib-bibtex >= 0.4.0
+  - sphinxcontrib-bibtex >= 0.4.2
 
 To install them, you should first install pip and setuptools (for instance,
 with `apt install python3-pip python3-setuptools` on Debian / Ubuntu) then run:
@@ -68,7 +68,7 @@ install them with:
 Or if you want to use less disk space:
 
     apt install texlive-latex-extra texlive-fonts-recommended texlive-xetex \
-                latexmk xindy
+                latexmk xindy fonts-freefont-otf
 
 Compilation
 -----------
diff --git a/doc/changelog/11-infrastructure-and-dependencies/12224-gdef_alias.rst b/doc/changelog/11-infrastructure-and-dependencies/12224-gdef_alias.rst
new file mode 100644
index 0000000000..35a618ea8d
--- /dev/null
+++ b/doc/changelog/11-infrastructure-and-dependencies/12224-gdef_alias.rst
@@ -0,0 +1,6 @@
+- **Changed:**
+  Minimal versions of dependencies for building the reference manual:
+  now requires Sphinx 2.3.1+, sphinx_rtd_theme 0.4.3+ and
+  sphinxcontrib-bibtex 0.4.2+
+  (`#12224 <https://github.com/coq/coq/pull/12224>`_,
+  by Jim Fehrle and Théo Zimmermann).
diff --git a/doc/sphinx/conf.py b/doc/sphinx/conf.py
index 4136b406de..fabf7a519f 100755
--- a/doc/sphinx/conf.py
+++ b/doc/sphinx/conf.py
@@ -46,7 +46,7 @@ with open("refman-preamble.rst") as s:
 # -- General configuration ------------------------------------------------
 
 # If your documentation needs a minimal Sphinx version, state it here.
-needs_sphinx = '1.8.0'
+needs_sphinx = '2.3.1'
 
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom