Prefer com.palantir.common:streams MoreIterables.partition over Iterables.partition by schlosna · Pull Request #68 · palantir/baseline-error-prone

schlosna · 2026-01-22T19:42:31Z

Before this PR

Uses of Guava's Iterables.partition preallocates an array of partition size, which can introduce excessive allocations in cases where the input iterable is smaller than the partition size.

After this PR

==COMMIT_MSG==
Prefer use of atlasdb-commons IterableUtils.partition over Iterables.partition

The com.palantir.common:streams MoreIterables.partition implementation avoids this and provides several optimizations when the input iterable is an ImmutableCollection to return sublists.
==COMMIT_MSG==

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changelog-app · 2026-01-22T19:42:35Z

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Prefer use of atlasdb-commons IterableUtils.partition over Iterables.partition

The atlasdb-commons IterableUtils.partition implementation avoids this and provides several optimizations when the input iterable is an ImmutableCollection to return sublists.

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Prefer use of atlasdb-commons IterableUtils.partition over Iterables.partition

The atlasdb-commons IterableUtils.partition implementation avoids this and provides several optimizations when the input iterable is an ImmutableCollection to return sublists. (#68)

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aldexis · 2026-01-23T09:39:56Z

-                        .build();
+                return fix(tree, state, "com.google.common.collect.Lists");
            }
+            return fix(tree, state, "com.palantir.common.collect.IterableUtils");


Now that atlasdb is closed-source, I'm not sure it's a good thing to put fixes using internal classes in our public error-prone packages, as this makes it less reusable for others.
Do you think we could put IterableUtils in some of our OSS packages instead? (if needed, maybe having a collection-utils repo/library could be useful?)

Looking at landing this in streams' MoreIterables palantir/streams#653

updated to use MoreIterables.partition in streams 2.6.0+

aldexis

Lgtm - just one nit and one question. I'll schedule a reminder to come back to this in a week to check progress of the streams 2.6.0 rollout

aldexis · 2026-02-03T09:24:32Z

-                        .build();
+                return fix(tree, state, "com.google.common.collect.Lists");
            }
+            return fix(tree, state, "com.palantir.common.streams.MoreIterables");


Out of curiosity, is there a way to check whether that class is on the classpath? Otherwise, let's wait a bit before merging this such that streams 2.6.0 is upgraded in more places (I'll track to come back to this in a week) - see https://pl.ntr/2zk

@schlosna I haven't forgotten about this by the way, and have been checking every few days on the rollout progress for streams 2.6.0. It seems like we still have ~30 repos that are somehow still on 2.5.0, so I'm still a bit hesitant to merge something that will break baseline-error-prone upgrades due to failing compilation, but the number continues to go down over time. I'll be ooto for the next 10 days, so I'll check back in after I'm back

aldexis · 2026-02-03T09:27:39Z

+                        "import static com.google.common.collect.Iterables.partition;",
+                        "class Test {",
+                        "  void test(Iterable<String> items) {",
+                        "    // BUG: Diagnostic contains: Prefer com.palantir.common.streams.MoreIterables.partition",
+                        "    partition(items, 10);",
                        "  }",


nit: At least for new ones (but ideally for this entire file), let's use code blocks, to make it easier to read

Suggested change

"import static com.google.common.collect.Iterables.partition;",

"class Test {",

" void test(Iterable<String> items) {",

" // BUG: Diagnostic contains: Prefer com.palantir.common.streams.MoreIterables.partition",

" partition(items, 10);",

" }",

// language=Java

"""

import static com.google.common.collect.Iterables.partition;

class Test {

void test(Iterable<String> items) {

// BUG: Diagnostic contains: Prefer com.palantir.common.streams.MoreIterables.partition

partition(items, 10);

}

"""

will update this in a bit. may create a separate 🤖 PR to migrate all the old tests

Prefer atlasdb-commons IterableUtils.partition over Iterables.partition

4436113

schlosna requested a review from Copilot January 22, 2026 20:00

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schlosna requested a review from Copilot January 22, 2026 22:51

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schlosna requested a review from Copilot January 23, 2026 01:16

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aldexis reviewed Jan 23, 2026

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schlosna changed the title ~~Prefer atlasdb-commons IterableUtils.partition over Iterables.partition~~ Prefer com.palantir.common:streams MoreIterables.partition over Iterables.partition Jan 26, 2026

Use com.palantir.common:streams MoreIterables.partition

51d570e

schlosna force-pushed the davids/partition branch from 1840493 to 51d570e Compare February 2, 2026 12:59

schlosna added autorelease merge when ready labels Feb 3, 2026

aldexis reviewed Feb 3, 2026

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schlosna commented Jan 22, 2026 •

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changelog-app Bot commented Jan 22, 2026 •

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