Rename lockdirs to discourage checking them into version control

Dune's lock directories are currently not portable. Naming them
"dune.lock" might suggest to users of other packgae managers that it is
safe to check them into version control and share them between
developers potentially using different machines. To discourage this
behaviour, lockdirs are renamed from "dune.lock" to
".dune-solution-cache". The fact that this directory begins with a
period and contains the word "cache" should hopefully discourage users
from checking them into version control.

For the same reason, the collection of dev tool lockdirs is renamed from
"dev-tools.locks" to ".dune-tools-solution-cache".

In the future it's likely we will enable portable lock directories by
default, at which point they will become safe to check into version
control. At this point we can change the default lock directory name
back to "dune.lock" and encourage checking them into version control.

Signed-off-by: Stephen Sherratt <[email protected]>

Author: gridbugs

bin/common.ml

@@ -246,7 +246,7 @@ module Options_implied_by_dash_p = struct
         & opt_all ~vopt:true bool [ false ]
         & info [ "require-dune-project-file" ] ~docs ~doc)
     and+ ignore_lock_dir =
-      let doc = "Ignore dune.lock/ directory." in
+      let doc = "Ignore .dune-solution-cache/ directory." in
       Arg.(value & flag & info [ "ignore-lock-dir" ] ~docs ~doc)
     in
     { root

bin/pkg/outdated.ml

@@ -93,7 +93,7 @@ let info =
     ; `P "For example:"
     ; `Pre "    \\$ dune pkg outdated"
     ; `Noblank
-    ; `Pre "    1/2 packages in dune.lock are outdated."
+    ; `Pre "    1/2 packages in .dune-solution-cache are outdated."
     ; `Noblank
     ; `Pre "    - ocaml 4.14.1 < 5.1.0"
     ; `Noblank

bin/pkg/pkg_common.ml

@@ -181,7 +181,8 @@ module Lock_dirs_arg = struct
                []
                ~docv:"LOCKDIRS"
                ~doc:
-                 "Lock directories to check for outdated packages. Defaults to dune.lock.")
+                 "Lock directories to check for outdated packages. Defaults to \
+                  .dune-solution-cache.")
        in
        Selected (List.map arg ~f:Path.Source.of_string))
       (let+ _all =

doc/explanation/package-management.md

@@ -101,7 +101,7 @@ archives to download (since there is no central location for all archives), the
 build instructions (since each package can use its own way of building), and
 additional metadata like the system packages it depends upon.
 
-The information is stored in a directory (`dune.lock` by default) as separate
+The information is stored in a directory (`.dune-solution-cache` by default) as separate
 files, to reduce potential merge conflicts and simplify code review. Storing
 additional files like patches is also simpler this way.
 

doc/reference/dune-workspace/context.rst

@@ -17,7 +17,7 @@ the description of an opam switch, as follows:
 
 -  ``(lock_dir <path>)`` specifies the lock directory that will be used for
    building this context (if any). If no lock directory is specified
-   ``dune.lock`` will be used. See the
+   ``.dune-solution-cache`` will be used. See the
    :doc:`/reference/dune-workspace/lock_dir` stanza for lock directory
    configuration options.
 

doc/reference/dune-workspace/lock_dir.rst

@@ -19,7 +19,7 @@ changed if desired.
    .. describe:: (path <string>)
 
       The location in the source tree where the lock directory will be
-      created or read from. If not specified defaults to ``dune.lock``.
+      created or read from. If not specified defaults to ``.dune-solution-cache``.
 
    .. describe:: (repositories <name list>)
 

doc/tutorials/dune-package-management/dependencies.md

@@ -26,7 +26,7 @@ to update our lock directory with the new packages.
 
 ```
 $ dune pkg lock
-Solution for dune.lock:
+Solution for .dune-solution-cache:
 - base-unix.base
 - fmt.0.9.0
 - ocaml.5.2.0
@@ -112,7 +112,7 @@ package is locked:
 
 ```
 $ dune pkg lock
-Solution for dune.lock:
+Solution for .dune-solution-cache:
 - base-unix.base
 - fmt.0.9.0
 - ocaml.5.2.0

doc/tutorials/dune-package-management/pinning.md

@@ -31,7 +31,7 @@ the information from the selected package repositories.
 
 ```
 $ dune pkg lock
-Solution for dune.lock:
+Solution for .dune-solution-cache:
 - base-unix.base
 - fmt.dev
 - ocaml.5.0.0

doc/tutorials/dune-package-management/repos.md

@@ -35,7 +35,7 @@ dependencies changes accordingly:
 
 ```
 $ dune pkg lock
-Solution for dune.lock:
+Solution for .dune-solution-cache:
 - base-unix.base
 - fmt.0.9.0
 - ocaml.5.0.0

doc/tutorials/dune-package-management/setup.md

@@ -63,7 +63,7 @@ This is easily done with a new Dune command:
 
 ```
 $ dune pkg lock
-Solution for dune.lock:
+Solution for .dune-solution-cache:
 - ocaml.5.2.0
 - ocaml-base-compiler.5.2.0
 - ocaml-config.3