CI: Enable the verbose mode in the mkmf.rb.

.github/workflows/test.yml

@@ -42,6 +42,11 @@ jobs:
       - name: depends
         run:  bundle install
 
+      # Enable the verbose option in mkmf.rb to print the compiling commands.
+      - name: enable mkmf verbose
+        run:  tool/enable-mkmf-verbose
+        if: runner.os == 'Linux' || runner.os == 'macOS'
+
       - name: compile
         run:  rake compile -- --enable-debug
 
@@ -129,6 +134,10 @@ jobs:
       - name: depends
         run:  bundle install
 
+      - name: enable mkmf verbose
+        run:  tool/enable-mkmf-verbose
+        if: runner.os == 'Linux' || runner.os == 'macOS'
+
       - name: compile
         run:  rake compile -- --enable-debug --with-openssl-dir=$HOME/.openssl/${{ matrix.openssl }}
 

tool/enable-mkmf-verbose

@@ -0,0 +1,24 @@
+#!/bin/sh
+
+set -eux
+
+gem_home="$(gem environment home)"
+mkmf_rb_path="$(find "${gem_home}"/../.. -name mkmf.rb)"
+
+# Backup the original file.
+cp -p "${mkmf_rb_path}" "${mkmf_rb_path}.orig"
+
+# Replace the target line to set the verbose option.
+sed -i -e 's/^V = .*/V = 1/' "${mkmf_rb_path}"
+
+# Print the difference between the original and modified file. This is useful
+# to debug when the `mkmf.rb` may change in the future. And check if the
+#`mkmf.rb` was modified. Because the `sed` command returns the exit status 0 no
+# matter it replaces successfully or not.
+if diff "${mkmf_rb_path}.orig" "${mkmf_rb_path}"; then
+  echo "error: ${mkmf_rb_path} was not modified." 1>&2
+  exit 1
+elif [ "${?}" != 1 ]; then
+  echo "error: diff was failed." 1>&2
+  exit 1
+fi