Allow building 27+ docs via ./otp_build download_ex_doc

We also make sure to build more stuff in CI to cover more
functionality, and fix a bug where multiple doc targets
couldn't be bit simultaneously

Further info:
- ex_doc is not installed to the post- kerl activation
bin path (nor is it found in the target install folder)

.github/workflows/ci.yml

@@ -48,6 +48,7 @@ jobs:
               echo '_KERL_PREFIX_GIT=git' >> $GITHUB_ENV
               echo '_KERL_PREFIX_GIT_TARGET=https://github.com/erlang/otp.git' >> $GITHUB_ENV
               echo 'KERL_BUILD_DOCS=yes' >> $GITHUB_ENV
+              echo 'KERL_DOC_TARGETS="html chunks"' >> $GITHUB_ENV
               _KERL_REL=git
               ;;
             *)

README.md

@@ -445,12 +445,12 @@ created via `kerl build git...`, and according to `KERL_INSTALL_HTMLDOCS` and `K
 Default: `chunks`
 Available targets:
 
-- `man`: install manpage docs.
+- `man` (dropped in OTP 27): install manpage docs.
 - `html`: install HTML docs.
-- `pdf`: install PDF docs.
+- `pdf` (dropped in OTP 27): install PDF docs.
 - `chunks`: install the "chunks" format to get documentation from the `erl` REPL.
 
-You can set multiple type of targets separated by space, example `$KERL_DOC_TARGETS="man html pdf chunks"`
+You can set multiple type of targets separated by space, example `KERL_DOC_TARGETS="html chunks"`
 
 #### `KERL_INSTALL_MANPAGES`
 

kerl

@@ -1009,6 +1009,9 @@ uname_r() {
 }
 
 _do_build() {
+    # $1: release (or git)
+    # $2: build name
+
     init_build_logfile "$1" "$2"
     log_build_entry "*** $(date) - kerl build $1 ***"
     log_build_entry "Build options:"
@@ -1170,12 +1173,20 @@ _do_build() {
     fi
     if [ -n "$KERL_BUILD_DOCS" ]; then
         notice "Building docs..."
+        OPT_VERSION=$(get_otp_version "$(cat OTP_VERSION)")
+        if [ "$OPT_VERSION" -ge 27 ]; then
+            # from OTP 27 on we depend on ex_doc to build the documentation
+            if ! log_build_cmd "./otp_build download_ex_doc"; then
+                fail_do_build "download_ex_doc failed." "$2" "$1"
+                return 1
+            fi
+        fi
         # shellcheck disable=SC2154  # KERL_DOC_TARGETS is referenced but not assigned
-        if ! log_build_cmd "make docs DOC_TARGETS=$KERL_DOC_TARGETS"; then
+        if ! log_build_cmd "make docs DOC_TARGETS=\"$KERL_DOC_TARGETS\""; then
             fail_do_build "building docs failed." "$2" "$1"
             return 1
         fi
-        if ! log_build_cmd "make release_docs DOC_TARGETS=$KERL_DOC_TARGETS RELEASE_ROOT=$KERL_BUILD_DIR/$2/release_$1"; then
+        if ! log_build_cmd "make release_docs DOC_TARGETS=\"$KERL_DOC_TARGETS\" RELEASE_ROOT=$KERL_BUILD_DIR/$2/release_$1"; then
             fail_do_build "release of docs failed." "$2" "$1"
             return 1
         fi
@@ -1697,7 +1708,7 @@ do_install() {
             error "couldn't cd into $ERL_TOP."
             exit_install
         fi
-        if ! log_install_cmd "ERL_TOP=$ERL_TOP make release_docs DOC_TARGETS=$KERL_DOC_TARGETS RELEASE_ROOT=$absdir"; then
+        if ! log_install_cmd "ERL_TOP=$ERL_TOP make release_docs DOC_TARGETS=\"$KERL_DOC_TARGETS\" RELEASE_ROOT=$absdir"; then
             show_install_logfile "couldn't install docs for Erlang/OTP $rel ($build_name) in $absdir"
             exit_install
         fi