github: constrain triggers for longer builds

The previous trigger would start duplicate builds for each new
label added to a PR. This commit locks this down a bit more so
that builds only run when the trigger label is added or on other
triggers when the label is present.

Signed-off-by: Gerwin Klein <gerwin.klein@proofcraft.systems>

.github/workflows/proof.yml

@@ -12,7 +12,11 @@ jobs:
   cproof:
     name: C Proofs
     runs-on: ubuntu-latest
-    if: contains(github.event.pull_request.labels.*.name, 'proof-test')
+    # run on any normal trigger when the label exists, and run when the label is added
+    # don't run again when other labels are added
+    if: ${{ github.event.action != 'labeled' &&
+              contains(github.event.pull_request.labels.*.name, 'proof-test') ||
+            github.event.action == 'labeled' && github.event.label == 'proof-test' }}
     strategy:
       fail-fast: false
       matrix:

.github/workflows/sel4test-sim.yml

@@ -18,6 +18,8 @@ jobs:
   sim:
     name: Simulation
     runs-on: ubuntu-latest
+    # do not re-run on PR labelling (already runs on other triggers):
+    if: ${{ github.event_name != 'pull_request' || github.event.action != 'labeled' }}
     strategy:
       matrix:
         march: [armv6a, armv7a, armv8a, nehalem, rv32imac, rv64imac]
@@ -36,8 +38,13 @@ jobs:
   hw-build:
     name: HW Build
     runs-on: ubuntu-latest
-    if: ${{ github.event.name == 'push' ||
-            contains(github.event.pull_request.labels.*.name, 'hw-build') }}
+    if: ${{ github.event_name == 'push' ||
+            github.event_name == 'pull_request' &&
+              github.event.action != 'labeled' &&
+              contains(github.event.pull_request.labels.*.name, 'hw-build') ||
+            github.event_name == 'pull_request' &&
+              github.event.action == 'labeled' &&
+              github.event.label == 'hw-build' }}
     strategy:
       fail-fast: false
       matrix: