refactor: Simplify the Dockerfiles

* the CLI option --build-arg=compiler="${OPAM_SWITCH}" is now useless
  (it had been introduced to be able to compile Coq versions < 8.7,
  while mathcomp-dev now requires Coq 8.7+)

* the "coqorg/base:bare" image now contains the two environment vars
  COMPILER and COMPILER_EDGE => clear COMPILER="" in mathcomp-dev's
  Dockerfile multi-stage build.

3 files changed, 11 insertions, 26 deletions

diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 2df217e..8be4087 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,7 +1,5 @@
 # Design:
 # - build stage (e.g. docker build -t mathcomp-dev:$IID_$SLUG_coq-8.7 .)
-#   - choice of the OCaml compiler: var OPAM_SWITCH in {base, edge}
-#     (Dockerfile containing: "opam switch set $compiler && eval $(opam env)")
 #   - all branches (not tags) => push on GitLab registry
 #   - GitHub PRs => push on GitLab and report back thanks to @coqbot
 # - test stage (image: mathcomp-dev:$IID_$SLUG_coq-8.7)
@@ -43,12 +41,11 @@ stages:
   variables:
     # This image will be built locally only (not pushed)
     IMAGE: "mathcomp-dev:make_coq-${COQ_VERSION}"
-    OPAM_SWITCH: "edge"
   before_script:
     - echo "${OPAM_SWITCH}"
     - echo "${COQ_VERSION}"
   script:
-    - docker build -f Dockerfile.make --pull --build-arg=coq_image="coqorg/coq:${COQ_VERSION}" --build-arg=compiler="${OPAM_SWITCH}" -t "${IMAGE}" .
+    - docker build -f Dockerfile.make --pull --build-arg=coq_image="coqorg/coq:${COQ_VERSION}" -t "${IMAGE}" .
   except:
     - tags
     - merge_requests
@@ -67,7 +64,6 @@ make-coq-latest:
     - docker:dind
   variables:
     IMAGE: "${CI_REGISTRY_IMAGE}:${CI_PIPELINE_IID}_${CI_COMMIT_REF_SLUG}_${CI_JOB_NAME}"
-    OPAM_SWITCH: "edge"
   before_script:
     - echo "${OPAM_SWITCH}"
     - echo "${CI_JOB_TOKEN}" | docker login -u "${CI_REGISTRY_USER}" --password-stdin "${CI_REGISTRY}"
@@ -85,7 +81,7 @@ make-coq-latest:
     - tags
     - merge_requests
     - schedules
-  
+
 coq-8.7:
   extends: .opam-build-once
 
diff --git a/Dockerfile b/Dockerfile
index 74ee396..65b7b30 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,18 +5,12 @@ WORKDIR /home/coq/mathcomp
 
 COPY . .
 
-ARG compiler="base"
-# other possible value: "edge"
-
 RUN ["/bin/bash", "--login", "-c", "set -x \
-  && declare -A switch_table \
-  && switch_table=( [\"base\"]=\"${COMPILER}\" [\"edge\"]=\"${COMPILER_EDGE}\" ) \
-  && opam_switch=\"${switch_table[${compiler}]}\" \
-  && [ -n \"opam_switch\" ] \
-  && opam switch set ${opam_switch} \
+  && [ -n \"${COMPILER_EDGE}\" ] \
+  && opam switch set \"${COMPILER_EDGE}\" \
   && eval $(opam env) \
-  && unset \"switch_table[${compiler}]\" \
-  && for sw in \"${switch_table[@]}\"; do if [ -n \"$sw\" ]; then opam switch remove -y \"${sw}\"; fi; done \
+  && [ -n \"${COMPILER}\" ] \
+  && opam switch remove -y \"${COMPILER}\" \
   && opam repository add --all-switches --set-default coq-extra-dev https://coq.inria.fr/opam/extra-dev \
   && opam repository add --all-switches --set-default coq-core-dev https://coq.inria.fr/opam/core-dev \
   && opam update -y \
@@ -33,6 +27,7 @@ RUN ["/bin/bash", "--login", "-c", "set -x \
 
 FROM coqorg/base:bare
 
+ENV COMPILER=""
 ENV MATHCOMP_VERSION="dev"
 ENV MATHCOMP_PACKAGE="coq-mathcomp-character"
 
diff --git a/Dockerfile.make b/Dockerfile.make
index bb8b653..8f305ae 100644
--- a/Dockerfile.make
+++ b/Dockerfile.make
@@ -5,18 +5,12 @@ WORKDIR /home/coq/mathcomp
 
 COPY . .
 
-ARG compiler="base"
-# other possible value: "edge"
-
 RUN ["/bin/bash", "--login", "-c", "set -x \
-  && declare -A switch_table \
-  && switch_table=( [\"base\"]=\"${COMPILER}\" [\"edge\"]=\"${COMPILER_EDGE}\" ) \
-  && opam_switch=\"${switch_table[${compiler}]}\" \
-  && [ -n \"opam_switch\" ] \
-  && opam switch set ${opam_switch} \
+  && [ -n \"${COMPILER_EDGE}\" ] \
+  && opam switch set \"${COMPILER_EDGE}\" \
   && eval $(opam env) \
-  && unset \"switch_table[${compiler}]\" \
-  && for sw in \"${switch_table[@]}\"; do [ -n \"$sw\" ] && opam switch remove -y \"${sw}\"; done \
+  && [ -n \"${COMPILER}\" ] \
+  && opam switch remove -y \"${COMPILER}\" \
   && opam repository add --all-switches --set-default coq-extra-dev https://coq.inria.fr/opam/extra-dev \
   && opam repository add --all-switches --set-default coq-core-dev https://coq.inria.fr/opam/core-dev \
   && opam update -y \