Make Bazel ignore build directories

[rdesgroppes]

What does this PR do?

Add **/build to REPO.bazel's ignore_directories(), partially replacing .bazelignore, and adjust CODEOWNERS accordingly.

Motivation

When bazel runs inside a Linux container on macOS via Docker Desktop, the workspace is typically mounted on a case-insensitive filesystem where BUILD and build are indistinguishable (docker/desktop-feedback#251).
#48455 addressed this for gazelle by restricting it to BUILD.bazel files only.
Bazel's own directory traversal, however, remained exposed to the same confusion.

REPO.bazel gained ignore_directories() in Bazel 8.0 (bazelbuild/bazel#24203), introduced as a complement to .bazelignore

to provide a migration path off of that weird single-purpose configuration file.

It supports Bazel's native glob() semantics, making **/build a natural fit.

Unfortunately (there's always a but...), it doesn't always work for symlinked directories (example):

ERROR: infinite symlink expansion detected
[start of symlink chain]
/go/src/github.com/DataDog/datadog-agent
/go/src/github.com/DataDog/datadog-agent/.cache/bazel/_bazel_root/8595a61ca643e2561dc364b98a410786/external/_main
[end of symlink chain]

... which was reported here: bazelbuild/bazel#24203 (comment)
So, for the time being, we also have to keep .bazelignore, but shrunk down to the bare minimum, until the issue is fixed upstream.

Additional Notes

Coming from Bazel 7, I was not aware of REPO.bazel, otherwise I would have added it in the first place instead of .bazelignore (#40153).

In CODEOWNERS, /MODULE.bazel* is replaced by /*.bazel* to cover REPO.bazel as well as any future root-level .bazel files.

In order to reproduce the infinite symlink expansion detected mentioned above, I had to configure my local bazel command line invocation as in CI, which surfaced the fact that tools/bazel* scripts had to be adjusted for this purpose. In particular, --repo_contents_cache= must be set when XDG_CACHE_HOME=$PWD/.cache (bazelbuild/bazel#26384). This is now fixed as well.

[agent-platform-auto-pr]

Files inventory check summary

File checks results against ancestor 5949a8cf:

Results for datadog-agent_7.79.0~devel.git.239.e02c86f.pipeline.104792216-1_amd64.deb:

No change detected

[JSGette]

Oh cool, I didn't know about this feature

[cit-pr-commenter-54b7da]

Regression Detector

Regression Detector Results

Metrics dashboard
Target profiles
Run ID: 78ec50e4-8e01-4689-a29d-ce1bbca0941e

Baseline: 4035f3a
Comparison: ea77cca
Diff

Optimization Goals: ✅ No significant changes detected

Experiments ignored for regressions

Regressions in experiments with settings containing erratic: true are ignored.

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	docker_containers_cpu	% cpu utilization	-1.98	[-4.91, +0.95]	1	Logs

Fine details of change detection per experiment

perf	experiment	goal	Δ mean %	Δ mean % CI	trials	links
➖	tcp_syslog_to_blackhole	ingress throughput	+0.46	[+0.34, +0.58]	1	Logs
➖	file_tree	memory utilization	+0.36	[+0.31, +0.42]	1	Logs
➖	ddot_metrics_sum_cumulativetodelta_exporter	memory utilization	+0.33	[+0.11, +0.56]	1	Logs
➖	otlp_ingest_metrics	memory utilization	+0.33	[+0.17, +0.49]	1	Logs
➖	docker_containers_memory	memory utilization	+0.32	[+0.25, +0.39]	1	Logs
➖	quality_gate_logs	% cpu utilization	+0.32	[-1.30, +1.94]	1	Logs bounds checks dashboard
➖	ddot_metrics_sum_delta	memory utilization	+0.31	[+0.14, +0.49]	1	Logs
➖	ddot_metrics_sum_cumulative	memory utilization	+0.11	[-0.03, +0.25]	1	Logs
➖	ddot_metrics	memory utilization	+0.06	[-0.11, +0.22]	1	Logs
➖	uds_dogstatsd_20mb_12k_contexts_20_senders	memory utilization	+0.04	[-0.02, +0.10]	1	Logs
➖	uds_dogstatsd_to_api	ingress throughput	+0.02	[-0.19, +0.22]	1	Logs
➖	file_to_blackhole_0ms_latency	egress throughput	+0.00	[-0.53, +0.53]	1	Logs
➖	uds_dogstatsd_to_api_v3	ingress throughput	-0.00	[-0.21, +0.20]	1	Logs
➖	tcp_dd_logs_filter_exclude	ingress throughput	-0.01	[-0.12, +0.10]	1	Logs
➖	file_to_blackhole_500ms_latency	egress throughput	-0.01	[-0.40, +0.38]	1	Logs
➖	quality_gate_idle_all_features	memory utilization	-0.02	[-0.05, +0.02]	1	Logs bounds checks dashboard
➖	file_to_blackhole_1000ms_latency	egress throughput	-0.02	[-0.46, +0.42]	1	Logs
➖	file_to_blackhole_100ms_latency	egress throughput	-0.03	[-0.11, +0.06]	1	Logs
➖	otlp_ingest_logs	memory utilization	-0.18	[-0.29, -0.08]	1	Logs
➖	ddot_logs	memory utilization	-0.28	[-0.34, -0.21]	1	Logs
➖	quality_gate_metrics_logs	memory utilization	-0.28	[-0.52, -0.04]	1	Logs bounds checks dashboard
➖	quality_gate_idle	memory utilization	-0.63	[-0.68, -0.58]	1	Logs bounds checks dashboard
➖	docker_containers_cpu	% cpu utilization	-1.98	[-4.91, +0.95]	1	Logs

Bounds Checks: ✅ Passed

perf	experiment	bounds_check_name	replicates_passed	observed_value	links
✅	docker_containers_cpu	simple_check_run	10/10	695 ≥ 26
✅	docker_containers_memory	memory_usage	10/10	272.65MiB ≤ 370MiB
✅	docker_containers_memory	simple_check_run	10/10	556 ≥ 26
✅	file_to_blackhole_0ms_latency	memory_usage	10/10	0.19GiB ≤ 1.20GiB
✅	file_to_blackhole_0ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_1000ms_latency	memory_usage	10/10	0.24GiB ≤ 1.20GiB
✅	file_to_blackhole_1000ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_100ms_latency	memory_usage	10/10	0.19GiB ≤ 1.20GiB
✅	file_to_blackhole_100ms_latency	missed_bytes	10/10	0B = 0B
✅	file_to_blackhole_500ms_latency	memory_usage	10/10	0.22GiB ≤ 1.20GiB
✅	file_to_blackhole_500ms_latency	missed_bytes	10/10	0B = 0B
✅	quality_gate_idle	intake_connections	10/10	3 = 3	bounds checks dashboard
✅	quality_gate_idle	memory_usage	10/10	172.96MiB ≤ 175MiB	bounds checks dashboard
✅	quality_gate_idle_all_features	intake_connections	10/10	3 = 3	bounds checks dashboard
✅	quality_gate_idle_all_features	memory_usage	10/10	493.16MiB ≤ 550MiB	bounds checks dashboard
✅	quality_gate_logs	intake_connections	10/10	4 ≤ 6	bounds checks dashboard
✅	quality_gate_logs	memory_usage	10/10	205.06MiB ≤ 220MiB	bounds checks dashboard
✅	quality_gate_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard
✅	quality_gate_metrics_logs	cpu_usage	10/10	363.59 ≤ 2000	bounds checks dashboard
✅	quality_gate_metrics_logs	intake_connections	10/10	4 ≤ 6	bounds checks dashboard
✅	quality_gate_metrics_logs	memory_usage	10/10	418.93MiB ≤ 475MiB	bounds checks dashboard
✅	quality_gate_metrics_logs	missed_bytes	10/10	0B = 0B	bounds checks dashboard

Explanation

Confidence level: 90.00%
Effect size tolerance: |Δ mean %| ≥ 5.00%

Performance changes are noted in the perf column of each table:

• ✅ = significantly better comparison variant performance
• ❌ = significantly worse comparison variant performance
• ➖ = no significant change in performance

A regression test is an A/B test of target performance in a repeatable rig, where "performance" is measured as "comparison variant minus baseline variant" for an optimization goal (e.g., ingress throughput). Due to intrinsic variability in measuring that goal, we can only estimate its mean value for each experiment; we report uncertainty in that value as a 90.00% confidence interval denoted "Δ mean % CI".

For each experiment, we decide whether a change in performance is a "regression" -- a change worth investigating further -- if all of the following criteria are true:

1. Its estimated |Δ mean %| ≥ 5.00%, indicating the change is big enough to merit a closer look.

2. Its 90.00% confidence interval "Δ mean % CI" does not contain zero, indicating that if our statistical model is accurate, there is at least a 90.00% chance there is a difference in performance between baseline and comparison variants.

3. Its configuration does not mark it "erratic".

CI Pass/Fail Decision

✅ Passed. All Quality Gates passed.

• quality_gate_idle, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check cpu_usage: 10/10 replicas passed. Gate passed.
• quality_gate_metrics_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check memory_usage: 10/10 replicas passed. Gate passed.
• quality_gate_idle_all_features, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check missed_bytes: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check intake_connections: 10/10 replicas passed. Gate passed.
• quality_gate_logs, bounds check memory_usage: 10/10 replicas passed. Gate passed.