patch_sync: Filter patches better

This commit introduces better patch filtering. Specifically,
* it prevents patches from being reintroduced to repos which
  already have those patches in their own PATCHES.json.
* it only applies android patches which are within the
  desired version range.

BUG=b:209493133
TEST=patch_sync transpose --no-commit -s <...>

Change-Id: I667a095395a36edf290e5e652ae40efaa2df7d57
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/3382194
Reviewed-by: George Burgess <gbiv@chromium.org>
Tested-by: Jordan Abrahams-Whitehead <ajordanr@google.com>
Commit-Queue: Jordan Abrahams-Whitehead <ajordanr@google.com>

2 files changed, 59 insertions, 0 deletions

diff --git a/llvm_tools/patch_sync/src/android_utils.rs b/llvm_tools/patch_sync/src/android_utils.rs
new file mode 100644
index 00000000..c6c1cd50
--- /dev/null
+++ b/llvm_tools/patch_sync/src/android_utils.rs
@@ -0,0 +1,33 @@
+use std::path::Path;
+use std::process::Command;
+
+use anyhow::{bail, ensure, Result};
+
+/// Return the Android checkout's current llvm version.
+///
+/// This uses android_version.get_svn_revision_number, a python function
+/// that can't be executed directly. We spawn a Python3 program
+/// to run it and get the result from that.
+pub fn get_android_llvm_version(android_checkout: &Path) -> Result<String> {
+    let mut command = Command::new("python3");
+    let llvm_android_dir = android_checkout.join("toolchain/llvm_android");
+    ensure!(
+        llvm_android_dir.is_dir(),
+        "can't get android llvm version; {} is not a directory",
+        llvm_android_dir.display()
+    );
+    command.current_dir(llvm_android_dir);
+    command.args([
+        "-c",
+        "import android_version; print(android_version.get_svn_revision_number(), end='')",
+    ]);
+    let output = command.output()?;
+    if !output.status.success() {
+        bail!(
+            "could not get android llvm version: {}",
+            String::from_utf8_lossy(&output.stderr)
+        );
+    }
+    let out_string = String::from_utf8(output.stdout)?.trim().to_string();
+    Ok(out_string)
+}
diff --git a/llvm_tools/patch_sync/src/main.rs b/llvm_tools/patch_sync/src/main.rs
index bfcba584..9616716c 100644
--- a/llvm_tools/patch_sync/src/main.rs
+++ b/llvm_tools/patch_sync/src/main.rs
@@ -1,3 +1,4 @@
+mod android_utils;
 mod patch_parsing;
 mod version_control;
 
@@ -103,6 +104,31 @@ fn transpose_subcmd(args: TransposeOpt) -> Result<()> {
     )
     .context("finding new patches for android")?;
 
+    // Have to ignore patches that are already at the destination, even if
+    // the patches are new.
+    let new_cros_patches = new_cros_patches.subtract(&cur_android_collection)?;
+    let new_android_patches = new_android_patches.subtract(&cur_cros_collection)?;
+
+    // Need to do an extra filtering step for Android, as AOSP doesn't
+    // want patches outside of the start/end bounds.
+    let android_llvm_version: u64 = {
+        let android_llvm_version_str =
+            android_utils::get_android_llvm_version(&ctx.android_checkout)?;
+        android_llvm_version_str.parse::<u64>().with_context(|| {
+            format!(
+                "converting llvm version to u64: '{}'",
+                android_llvm_version_str
+            )
+        })?
+    };
+    let new_android_patches =
+        new_android_patches.filter_patches(|p| match (p.start_version, p.end_version) {
+            (Some(start), Some(end)) => start <= android_llvm_version && android_llvm_version < end,
+            (Some(start), None) => start <= android_llvm_version,
+            (None, Some(end)) => android_llvm_version < end,
+            (None, None) => true,
+        });
+
     if args.verbose {
         display_patches("New patches from Chromium OS", &new_cros_patches);
         display_patches("New patches from Android", &new_android_patches);