Index taskcluster tasks by merge parents if available.

.taskcluster.yml

@@ -30,10 +30,12 @@ tasks:
           - '--login'
           - '-e'
           - '-c'
+          # A depth of 25 is used to work around `git show` ignoring
+          # any provided format with a depth of 1.
           - >-
             git init repo &&
             cd repo &&
-            git fetch --depth 1 "$GIT_URL" "$GIT_REF" &&
+            git fetch --depth 25 "$GIT_URL" "$GIT_REF" &&
             git reset --hard "$GIT_SHA" &&
             python3 etc/taskcluster/decision_task.py
   in:

etc/taskcluster/decision_task.py

@@ -17,6 +17,8 @@ def main(task_for):
         )
 
     if task_for == "github-push":
+        CONFIG.init_task_id()
+
         # FIXME https://github.com/servo/servo/issues/22325 implement these:
         linux_arm32_dev = linux_arm64_dev = lambda: None
 
@@ -193,12 +195,12 @@ def linux_tidy_unit_docs():
             git bundle create docs.bundle HEAD
         """)
         .with_artifacts("/repo/target/doc/docs.bundle")
-        .find_or_create("docs." + CONFIG.git_sha)
+        .find_or_create("docs." + CONFIG.task_id)
     )
 
 
 def upload_docs():
-    docs_build_task_id = decisionlib.Task.find("docs." + CONFIG.git_sha)
+    docs_build_task_id = decisionlib.Task.find("docs." + CONFIG.task_id)
     return (
         linux_task("Upload docs to GitHub Pages")
         .with_treeherder("Linux x64", "DocUpload")
@@ -233,7 +235,7 @@ def macos_unit():
             ./mach package --dev
             ./etc/ci/lockfile_changed.sh
         """)
-        .find_or_create("macos_unit." + CONFIG.git_sha)
+        .find_or_create("macos_unit." + CONFIG.task_id)
     )
 
 
@@ -266,7 +268,7 @@ def android_arm32_dev_from_macos():
             ./mach bootstrap-android --accept-all-licences --build
             ./mach build --android --dev --verbose
         """)
-        .find_or_create("android_arm32_dev.macos." + CONFIG.git_sha)
+        .find_or_create("android_arm32_dev.macos." + CONFIG.task_id)
     )
 
 
@@ -279,7 +281,7 @@ def android_arm32_dev():
             ./etc/ci/lockfile_changed.sh
             python ./etc/ci/check_dynamic_symbols.py
         """)
-        .find_or_create("android_arm32_dev." + CONFIG.git_sha)
+        .find_or_create("android_arm32_dev." + CONFIG.task_id)
     )
 
 
@@ -303,7 +305,7 @@ def android_nightly():
             "/repo/target/android/i686-linux-android/release/servoapp.apk",
             "/repo/target/android/i686-linux-android/release/servoview.aar",
         )
-        .find_or_create("build.android_nightlies." + CONFIG.git_sha)
+        .find_or_create("build.android_nightlies." + CONFIG.task_id)
     )
 
 
@@ -316,7 +318,7 @@ def android_arm32_release():
             "/repo/target/android/armv7-linux-androideabi/release/servoapp.apk",
             "/repo/target/android/armv7-linux-androideabi/release/servoview.aar",
         )
-        .find_or_create("build.android_armv7_release." + CONFIG.git_sha)
+        .find_or_create("build.android_armv7_release." + CONFIG.task_id)
     )
 
 
@@ -329,7 +331,7 @@ def android_x86_release():
             "/repo/target/android/i686-linux-android/release/servoapp.apk",
             "/repo/target/android/i686-linux-android/release/servoview.aar",
         )
-        .find_or_create("build.android_x86_release." + CONFIG.git_sha)
+        .find_or_create("build.android_x86_release." + CONFIG.task_id)
     )
 
 
@@ -352,7 +354,7 @@ def android_x86_wpt():
                 /_mozilla/mozilla/DOMParser.html \
                 /_mozilla/mozilla/webgl/context_creation_error.html
         """)
-        .find_or_create("android_x86_release." + CONFIG.git_sha)
+        .find_or_create("android_x86_release." + CONFIG.task_id)
     )
 
 
@@ -366,7 +368,7 @@ def windows_x86():
         .with_script(
             "python mach build --dev --target i686-pc-windows-msvc",
         )
-        .find_or_create("build.windows_x86_dev." + CONFIG.git_sha)
+        .find_or_create("build.windows_x86_dev." + CONFIG.task_id)
     )
 
 
@@ -385,7 +387,7 @@ def windows_unit():
         )
         .with_artifacts("repo/target/debug/msi/Servo.exe",
                         "repo/target/debug/msi/Servo.zip")
-        .find_or_create("build.windows_x64_dev." + CONFIG.git_sha)
+        .find_or_create("build.windows_x64_dev." + CONFIG.task_id)
     )
 
 
@@ -397,7 +399,7 @@ def windows_release():
                      "mach package --release")
         .with_artifacts("repo/target/release/msi/Servo.exe",
                         "repo/target/release/msi/Servo.zip")
-        .find_or_create("build.windows_x64_release." + CONFIG.git_sha)
+        .find_or_create("build.windows_x64_release." + CONFIG.task_id)
     )
 
 
@@ -413,7 +415,7 @@ def windows_nightly():
                      "mach upload-nightly windows-msvc --secret-from-taskcluster")
         .with_artifacts("repo/target/release/msi/Servo.exe",
                         "repo/target/release/msi/Servo.zip")
-        .find_or_create("build.windows_x64_nightly." + CONFIG.git_sha)
+        .find_or_create("build.windows_x64_nightly." + CONFIG.task_id)
     )
 
 
@@ -430,7 +432,7 @@ def linux_nightly():
             "./mach upload-nightly linux --secret-from-taskcluster",
         )
         .with_artifacts("/repo/target/release/servo-tech-demo.tar.gz")
-        .find_or_create("build.linux_x64_nightly" + CONFIG.git_sha)
+        .find_or_create("build.linux_x64_nightly" + CONFIG.task_id)
     )
 
 
@@ -447,7 +449,7 @@ def linux_wpt():
                 target/release/build/osmesa-src-*/out/lib/gallium
         """)
         .with_artifacts("/target.tar.gz")
-        .find_or_create("build.linux_x64_release~assertions" + CONFIG.git_sha)
+        .find_or_create("build.linux_x64_release~assertions" + CONFIG.task_id)
     )
     def linux_run_task(name):
         return linux_task(name).with_dockerfile(dockerfile_path("run"))
@@ -470,7 +472,7 @@ def macos_nightly():
             "./mach upload-nightly mac --secret-from-taskcluster",
         )
         .with_artifacts("repo/target/release/servo-tech-demo.dmg")
-        .find_or_create("build.mac_x64_nightly." + CONFIG.git_sha)
+        .find_or_create("build.mac_x64_nightly." + CONFIG.task_id)
     )
 
 
@@ -500,7 +502,7 @@ def update_wpt():
             ./etc/ci/update-wpt-checkout open-pr
             ./etc/ci/update-wpt-checkout cleanup
         """)
-        .find_or_create("wpt_update." + CONFIG.git_sha)
+        .find_or_create("wpt_update." + CONFIG.task_id)
     )
 
 
@@ -518,7 +520,7 @@ def macos_release_build():
                 target/release/build/osmesa-src-*/out/src/mapi/shared-glapi/.libs
         """)
         .with_artifacts("repo/target.tar.gz")
-        .find_or_create("build.macos_x64_release." + CONFIG.git_sha)
+        .find_or_create("build.macos_x64_release." + CONFIG.task_id)
     )
 
 
@@ -606,7 +608,7 @@ def wpt_chunks(platform, make_chunk_task, build_task, total_chunks, processes,
             if word.endswith(".log")
         ])
         platform_id = platform.replace(" ", "_").lower()
-        task.find_or_create("%s_wpt_%s.%s" % (platform_id, this_chunk, CONFIG.git_sha))
+        task.find_or_create("%s_wpt_%s.%s" % (platform_id, this_chunk, CONFIG.task_id))
 
 
 def daily_tasks_setup():

etc/taskcluster/decisionlib.py

@@ -57,9 +57,21 @@ class Config:
         self.git_ref = os.environ.get("GIT_REF")
         self.git_sha = os.environ.get("GIT_SHA")
 
+    def init_task_id(self):
+        # If the head commit is a merge, we want to generate a unique task id which incorporates
+        # the merge parents rather that the actual sha of the merge commit. This ensures that tasks
+        # can be reused if the tree is in an identical state. Otherwise, if the head commit is
+        # not a merge, we can rely on the head commit sha for that purpose.
+        merge_parents_output = subprocess.check_output(["git", "show", "--format=%P", "HEAD"])
+        merge_parents = merge_parents_output.decode("utf8").strip().split(' ')
+        self.task_id = self.git_sha
+        if len(merge_parents) > 1:
+            self.task_id = '-'.join(merge_parents)
+
     def git_sha_is_current_head(self):
         output = subprocess.check_output(["git", "rev-parse", "HEAD"])
         self.git_sha = output.decode("utf8").strip()
+        self.init_task_id()
 
 
 class Shared: