tree c2727e05c84a307950654099b8b043e03607f547
parent c1b663788ed1ecf2ffd53781c98ae2291ee002cf
author Philipp Wollermann <philwo@chromium.org> 1783062558 +0900
committer gn-scoped@luci-project-accounts.iam.gserviceaccount.com <gn-scoped@luci-project-accounts.iam.gserviceaccount.com> 1788059606 -0700

docs: Document that copy() uses the toolchain's copy tool

The copy() target type does not have a built-in copy command; the actual
command is provided by the "copy" tool defined by the toolchain, and GN
errors out if no such tool exists. This is how Chromium customizes
copying (e.g. hard-linking for speed), but it was not documented
anywhere, so it was easy to assume copy() had a fixed built-in
implementation.

Add a "How the copy is performed" section to `gn help copy` explaining
the mechanism and showing how to override the tool, and cross-reference
it from the "copy" tool description in `gn help tool`. Regenerate
reference.md.

Change-Id: I0fbd42c540411b4e15b0385f6753b6679ee23483
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/23760
Reviewed-by: Takuto Ikuta <tikuta@google.com>
Reviewed-by: Matt Stark <msta@google.com>
Commit-Queue: Philipp Wollermann <philwo@chromium.org>