tree 2ab155fd21c4ac40c0915f12e85624f73197019c
parent f2f5b23ea7bf95492c683c046b5e7a624364e3b7
author Matt Stark <msta@google.com> 1778851924 +1000
committer gn-scoped@luci-project-accounts.iam.gserviceaccount.com <gn-scoped@luci-project-accounts.iam.gserviceaccount.com> 1779252736 -0700

Implement cycle detection and circular dependency handling in `gn suggest`.

When suggesting dependency changes, `gn suggest` now checks if the proposed
dependency would introduce a cycle. Specifically:

- Added `FindDependencyPath` to trace the shortest path of dependencies
  between targets.
- If adding the dependency from target A to target B would create a loop
  (because B already transitively depends on A), a warning is printed to
  trace the cycle.
- If any target in the cycle utilizes `allow_circular_includes_from`,
  warns the user that this is bad style and prints a suggestion template
  demonstrating how to refactor the target (e.g., by splitting it into
  a `source_set` for compilation units and a target for dependencies).
- Added corresponding unit tests in `command_suggest_unittest.cc` to verify
  the warning messages and suggestion templates.

Bug: 500845363
Change-Id: I2d3bf67372073f1aed9c3b1ae6d5a59b6a6a6964
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/22780
Commit-Queue: Matt Stark <msta@google.com>
Reviewed-by: Takuto Ikuta <tikuta@google.com>