René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Production build peak memory +53% after upgrading @angular/build 21.2.13 → 22.0.0 (same code, same esbuild version)","articleBody":"### Command\n\nbuild\n\n### Is this a regression?\n\n- [x] Yes, this behavior used to work in the previous version\n\n### The previous version in which this bug was not present was\n\n@angular/build 21.2.13 / Angular 21.2.15 / TS 5.9.3\n\n### Description\n\nAfter upgrading to Angular 22, our production build's peak memory rose from ~15.5GB to ~23.8GB (+53%), which started OOM-killing our 16GB CI runners. A/B measurement on the identical commit of a large Nx monorepo (~7,400 TS\n  files, ~2,250 components, single application target), cold build cache, default workers, sampling combined RSS of the full node + esbuild process tree every 3s:\n                    Toolchain                     │ Peak RSS │\n  @angular/build 21.2.13, Angular 21.2.15, TS 5.9.3 │ 15.5GB   │\n  @angular/build 22.0.0, Angular 22.0.0, TS 6.0.3   │ 23.8GB   │\n  @angular/build 22.0.1, Angular 22.0.0, TS 6.0.3   │ 22.3GB   │\n  \n  - esbuild is 0.28.0 in both setups (unchanged).\n  - The application code is identical in both runs (the v21 build needed only ignoreDeprecations adjusted in tsconfig).\n  - 22.0.1's stylesheet-bundler leak fixes (#33318) recover ~1.5GB but the bulk of the increase remains.\n  - NG_BUILD_MAX_WORKERS=2 makes peak memory worse (31.8GB), not better.\n  - Caveat: TypeScript necessarily moved 5.9.3 → 6.0.3 with the Angular major, so we cannot separate the TS 6 share of the increase from @angular/build 22 itself.\n  - Symptom on constrained machines: host OOM killer fires (or esbuild dies with fatal error: all goroutines are asleep - deadlock! when Node's --max-old-space-size exceeds physical RAM).\n\n\n### Minimal Reproduction\n\n  Private repo, so I can't share a reproduction, but happy to run instrumented builds / --stats-json / heap profiles on request.\n\n\n### Exception or Error\n\n```text\n\n```\n\n### Your Environment\n\n```text\nNode 24.16.0, npm 11.x, macOS 27 (arm64) + Linux CI, Nx 21.3.2\n```\n\n### Anything else relevant?\n\n_No response_","author":{"url":"https://github.com/t-barak","@type":"Person","name":"t-barak"},"datePublished":"2026-06-12T13:43:07.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":11},"url":"https://github.com/33368/angular-cli/issues/33368"}