[ci][check_versions] Refactor bash script

Deduplicate some logic.

Closes #307

.github/workflows/ci.yml

@@ -372,53 +372,56 @@ jobs:
           ver_zerocopy=$(version zerocopy)
           ver_zerocopy_derive=$(version zerocopy-derive)
 
-          # The non-dev dependency version (`.kind == null` filters out the dev
-          # dependency, and `.target == null` filters out the targeted version).
-          zerocopy_derive_dep_ver=$(cargo metadata --format-version 1 \
-            | jq -r ".packages[] | select(.name == \"zerocopy\").dependencies[] | select((.name == \"zerocopy-derive\") and .kind == null and .target == null).req")
+          # Usage: dependency-version <kind> <target>
+          function dependency-version {
+            KIND="$1"
+            TARGET="$2"
+            cargo metadata --format-version 1 \
+              | jq -r ".packages[] | select(.name == \"zerocopy\").dependencies[] | select((.name == \"zerocopy-derive\") and .kind == $KIND and .target == $TARGET).req"
+          }
+
+          # The non-dev dependency version (kind `null` filters out the dev
+          # dependency, and target `null` filters out the targeted version).
+          zerocopy_derive_dep_ver=$(dependency-version null null)
 
-          # The non-dev dependency, targeted version.
-          zerocopy_derive_targeted_ver=$(cargo metadata --format-version 1 \
-            | jq -r ".packages[] | select(.name == \"zerocopy\").dependencies[] | select((.name == \"zerocopy-derive\") and .kind == null and .target == \"cfg(any())\").req")
+          # The non-dev dependency, targeted version (kind `null` filters out
+          # the dev dependency).
+          zerocopy_derive_targeted_ver=$(dependency-version null '"cfg(any())"')
 
-          # The dev dependency version (`.kind == \"dev\"` selects only the dev
+          # The dev dependency version (kind `"dev"` selects only the dev
           # dependency).
-          zerocopy_derive_dev_dep_ver=$(cargo metadata --format-version 1 \
-            | jq -r ".packages[] | select(.name == \"zerocopy\").dependencies[] | select((.name == \"zerocopy-derive\") and .kind == \"dev\").req")
+          zerocopy_derive_dev_dep_ver=$(dependency-version '"dev"' null)
+
+          function assert-match {
+            VER_A="$1"
+            VER_B="$2"
+            SUCCESS_MSG="$3"
+            FAILURE_MSG="$4"
+            if [[ "$ver_zerocopy" == "$ver_zerocopy_derive" ]]; then
+              echo "$SUCCESS_MSG" | tee -a $GITHUB_STEP_SUMMARY
+            else
+              echo "$FAILURE_MSG" | tee -a $GITHUB_STEP_SUMMARY >&2
+              exit 1
+            fi
+          }
 
-          if [[ "$ver_zerocopy" == "$ver_zerocopy_derive" ]]; then
-            echo "Same crate version ($ver_zerocopy) found for zerocopy and zerocopy-derive." | tee -a $GITHUB_STEP_SUMMARY
-          else
-            echo "Different crate versions found for zerocopy ($ver_zerocopy) and zerocopy-derive ($ver_zerocopy_derive)." \
-              | tee -a $GITHUB_STEP_SUMMARY >&2
-            exit 1
-          fi
+          assert-match "$ver_zerocopy" "$ver_zerocopy_derive" \
+            "Same crate version ($ver_zerocopy) found for zerocopy and zerocopy-derive." \
+            "Different crate versions found for zerocopy ($ver_zerocopy) and zerocopy-derive ($ver_zerocopy_derive)."
 
           # Note the leading `=` sign - the dependency needs to be an exact one.
-          if [[ "=$ver_zerocopy_derive" == "$zerocopy_derive_dep_ver" ]]; then
-            echo "zerocopy depends upon same version of zerocopy-derive in-tree ($zerocopy_derive_dep_ver)." | tee -a $GITHUB_STEP_SUMMARY
-          else
-            echo "zerocopy depends upon different version of zerocopy-derive ($zerocopy_derive_dep_ver) than the one in-tree ($ver_zerocopy_derive)." \
-              | tee -a $GITHUB_STEP_SUMMARY >&2
-            exit 1
-          fi
+          assert-match "=$ver_zerocopy_derive" "$zerocopy_derive_dep_ver" \
+            "zerocopy depends upon same version of zerocopy-derive in-tree ($zerocopy_derive_dep_ver)." \
+            "zerocopy depends upon different version of zerocopy-derive ($zerocopy_derive_dep_ver) than the one in-tree ($ver_zerocopy_derive)."
 
-          if [[ "=$ver_zerocopy_derive" == "$zerocopy_derive_dev_dep_ver" ]]; then
-            echo "In dev mode, zerocopy depends upon same version of zerocopy-derive in-tree ($zerocopy_derive_dev_dep_ver)." | tee -a $GITHUB_STEP_SUMMARY
-          else
-            echo "In dev mode, zerocopy depends upon different version of zerocopy-derive ($zerocopy_derive_dev_dep_ver) than the one in-tree ($ver_zerocopy_derive)." \
-              | tee -a $GITHUB_STEP_SUMMARY >&2
-            exit 1
-          fi
+          # Note the leading `=` sign - the dependency needs to be an exact one.
+          assert-match "=$ver_zerocopy_derive" "$zerocopy_derive_dev_dep_ver" \
+            "In dev mode, zerocopy depends upon same version of zerocopy-derive in-tree ($zerocopy_derive_dev_dep_ver)." \
+            "In dev mode, zerocopy depends upon different version of zerocopy-derive ($zerocopy_derive_dev_dep_ver) than the one in-tree ($ver_zerocopy_derive)."
 
-          if [[ "$zerocopy_derive_dep_ver" == "$zerocopy_derive_targeted_ver" ]]; then
-            echo "Same crate version ($zerocopy_derive_dep_ver) found for optional and targeted zerocopy-derive dependency." \
-              | tee -a $GITHUB_STEP_SUMMARY
-          else
-            echo "Different crate versions found for optional ($zerocopy_derive_dep_ver) and targeted ($zerocopy_derive_targeted_ver) dependency." \
-              | tee -a $GITHUB_STEP_SUMMARY >&2
-            exit 1
-          fi
+          assert-match "$zerocopy_derive_dep_ver" "$zerocopy_derive_targeted_ver" \
+            "Same crate version ($zerocopy_derive_dep_ver) found for optional and targeted zerocopy-derive dependency." \
+            "Different crate versions found for optional ($zerocopy_derive_dep_ver) and targeted ($zerocopy_derive_targeted_ver) dependency."
 
   generate_cache:
     runs-on: ubuntu-latest