patch_sync: Filter patches by platform

Because some patch collections may contain
patches which don't apply to our given platform,
we don't want to attempt to lookup their hashes.

If we do, we may encounter a file-not-found error,
as those patches haven't been ported to this
platform.

Also fixes a bug where no_commit was inverted.

BUG=b:209493133
TEST=N/A

Change-Id: I8b86133dfc6361919174f9f9b392d756b4304d2b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/3364792
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, 35 insertions, 9 deletions

diff --git a/llvm_tools/patch_sync/src/main.rs b/llvm_tools/patch_sync/src/main.rs
index 081ce01a..f2d70edb 100644
--- a/llvm_tools/patch_sync/src/main.rs
+++ b/llvm_tools/patch_sync/src/main.rs
@@ -82,7 +82,8 @@ fn transpose_subcmd(args: TransposeOpt) -> Result<()> {
     // Chromium OS Patches ----------------------------------------------------
     let mut cur_cros_collection =
         patch_parsing::PatchCollection::parse_from_file(&cros_patches_path)
-            .context("parsing cros PATCHES.json")?;
+            .context("parsing cros PATCHES.json")?
+            .filter_patches(|p| p.platforms.contains("chromiumos"));
     let new_cros_patches: patch_parsing::PatchCollection = {
         let cros_old_patches_json = ctx.old_cros_patch_contents(&args.old_cros_ref)?;
         let old_cros_collection = patch_parsing::PatchCollection::parse_from_str(
@@ -95,7 +96,8 @@ fn transpose_subcmd(args: TransposeOpt) -> Result<()> {
     // Android Patches -------------------------------------------------------
     let mut cur_android_collection =
         patch_parsing::PatchCollection::parse_from_file(&android_patches_path)
-            .context("parsing android PATCHES.json")?;
+            .context("parsing android PATCHES.json")?
+            .filter_patches(|p| p.platforms.contains("android"));
     let new_android_patches: patch_parsing::PatchCollection = {
         let android_old_patches_json = ctx.old_android_patch_contents(&args.old_android_ref)?;
         let old_android_collection = patch_parsing::PatchCollection::parse_from_str(
@@ -105,18 +107,34 @@ fn transpose_subcmd(args: TransposeOpt) -> Result<()> {
         cur_android_collection.subtract(&old_android_collection)?
     };
 
+    if args.dry_run {
+        println!("--dry-run specified; skipping modifications");
+        return Ok(());
+    }
+
     // Transpose Patches -----------------------------------------------------
-    new_cros_patches.transpose_write(&mut cur_cros_collection)?;
-    new_android_patches.transpose_write(&mut cur_android_collection)?;
+    if !new_cros_patches.is_empty() {
+        new_cros_patches.transpose_write(&mut cur_android_collection)?;
+    }
+    if !new_android_patches.is_empty() {
+        new_android_patches.transpose_write(&mut cur_cros_collection)?;
+    }
 
-    if !args.no_commit {
+    if args.no_commit {
+        println!("--no-commit specified; not committing or uploading");
         return Ok(());
     }
     // Commit and upload for review ------------------------------------------
-    ctx.cros_repo_upload()
-        .context("uploading chromiumos changes")?;
-    ctx.android_repo_upload()
-        .context("uploading android changes")?;
+    // Note we want to check if the android patches are empty for CrOS, and
+    // vice versa. This is a little counterintuitive.
+    if !new_android_patches.is_empty() {
+        ctx.cros_repo_upload()
+            .context("uploading chromiumos changes")?;
+    }
+    if !new_cros_patches.is_empty() {
+        ctx.android_repo_upload()
+            .context("uploading android changes")?;
+    }
     Ok(())
 }
 
diff --git a/llvm_tools/patch_sync/src/patch_parsing.rs b/llvm_tools/patch_sync/src/patch_parsing.rs
index 733451ae..befa6ccb 100644
--- a/llvm_tools/patch_sync/src/patch_parsing.rs
+++ b/llvm_tools/patch_sync/src/patch_parsing.rs
@@ -44,6 +44,14 @@ impl PatchCollection {
         })
     }
 
+    /// Copy this collection with patches filtered by given criterion.
+    pub fn filter_patches(&self, f: impl FnMut(&PatchDictSchema) -> bool) -> Self {
+        Self {
+            patches: self.patches.iter().cloned().filter(f).collect(),
+            workdir: self.workdir.clone(),
+        }
+    }
+
     #[allow(dead_code)]
     /// Return true if the collection is tracking any patches.
     pub fn is_empty(&self) -> bool {