Implement logic of check-upstream

.github/workflows/check-upstream.main.kts

@@ -23,14 +23,22 @@ workflow(
     ) {
         uses(action = Checkout())
         run(
-            name = "Clone snakeyaml-engine",
-            command = "git clone https://bitbucket.org/snakeyaml/snakeyaml-engine.git && cd snakeyaml-engine"
+            name = "Clone snakeyaml-engine and check for changes",
+            command = """
+                git clone --branch master --single-branch https://bitbucket.org/snakeyaml/snakeyaml-engine.git
+                cd snakeyaml-engine
+                git log --oneline $(cat ../upstream-commit.txt)..master | wc -l > ../number-of-commits.txt
+            """.trimIndent(),
         )
         run(
-            name = "Calculate changes between the last synced change and current state",
-            // TODO: store this commit hash in a file
-            // TODO: get the numerical value (| wc -l)
-            command = "git log --oneline ef7ebe9c06e963e13f4ab465f300a0dd6f0940c9..master"
+            name = "Create an SVG with the number of commits",
+            command = """
+                echo "<svg viewBox=\"0 0 85 20\" xmlns=\"http://www.w3.org/2000/svg\"><style>.number { font: 13px sans-serif; }</style><text x=\"0\" y=\"0\" class=\"number\">${'$'}(cat number-of-commits.txt)</text></svg>" > badge.svg
+            """.trimIndent(),
+        )
+        run(
+            name = "Preview badge",
+            command = "cat badge.svg",
         )
     }
 }

.github/workflows/check-upstream.yaml

@@ -27,8 +27,14 @@ jobs:
     - id: 'step-0'
       uses: 'actions/checkout@v4'
     - id: 'step-1'
-      name: 'Clone snakeyaml-engine'
-      run: 'git clone https://bitbucket.org/snakeyaml/snakeyaml-engine.git && cd snakeyaml-engine'
+      name: 'Clone snakeyaml-engine and check for changes'
+      run: |-
+        git clone --branch master --single-branch https://bitbucket.org/snakeyaml/snakeyaml-engine.git
+        cd snakeyaml-engine
+        git log --oneline $(cat ../upstream-commit.txt)..master | wc -l > ../number-of-commits.txt
     - id: 'step-2'
-      name: 'Calculate changes between the last synced change and current state'
-      run: 'git log --oneline ef7ebe9c06e963e13f4ab465f300a0dd6f0940c9..master'
+      name: 'Create an SVG with the number of commits'
+      run: 'echo "<svg viewBox=\"0 0 85 20\" xmlns=\"http://www.w3.org/2000/svg\"><style>.number { font: 13px sans-serif; }</style><text x=\"0\" y=\"0\" class=\"number\">$(cat number-of-commits.txt)</text></svg>" > badge.svg'
+    - id: 'step-3'
+      name: 'Preview badge'
+      run: 'cat badge.svg'

upstream-commit.txt

@@ -0,0 +1 @@
+ef7ebe9c06e963e13f4ab465f300a0dd6f0940c9