add comments to gitlab CI, remove useless version stage

.gitlab-ci.yml

@@ -18,11 +18,14 @@ stages:
   - cache-cleanup
   - build-base
   - build
-  - version
   - test
 
 # TEMPLATES
 
+# this step uses cargo-sweep to clean up unneeded cruft that accumulates over time in the target dir. cargo clean is
+# not used because it simply rm -rf's the entire target directory (and thus prevents build caching). i would really like
+# to either replace this with a bash script, or to install cargo-sweep as a binary instead of building it from source
+# like this. i'd also like to add a step that checks to see whether the target dir exists, and exits early if not.
 .cargo-cleanup:
   stage: cache-cleanup
   allow_failure: true
@@ -30,11 +33,15 @@ stages:
     - cargo install cargo-sweep
     - cargo sweep -i
 
+# this builds a "base" version of fif with default features enabled. this is done separately from the main build step
+# for the purposes of caching - by building once *before* executing the parallel cargo-build step, we ensure that
+# cargo-build can reuse some cached stuff, rather than building from scratch every time.
 .cargo-build-base:
   stage: build-base
   script:
     cargo build --locked
 
+# build with various features on and off.
 .cargo-build:
   extends: .cargo-build-base
   stage: build
@@ -49,6 +56,7 @@ stages:
   script:
     cargo build --no-default-features --locked --features="json $FEATURES"
 
+# test with various features on and off.
 .cargo-test:
   extends: .cargo-build
   stage: test
@@ -57,6 +65,9 @@ stages:
 
 # LINT
 
+# run the included clippy.sh with "ci" mode on - clippy will exit with code 1 if anything at all is amiss. this is just
+# here to make sure i remember to run clippy.sh locally myself and fix/ignore all the warnings before committing, as i
+# should be.
 clippy:
   stage: lint
   script:
@@ -137,14 +148,6 @@ build-nightly:
       - target
       - .cargo
 
-# VERSION
-
-fif-version:
-  stage: version
-  needs: ["build-stable"]
-  script:
-    cargo run -- -V
-
 # TEST
 
 test-stable: