* Conveniently use local crates, including completely
unpublished crates.
-
* Perform out-of-tree builds, including in an account with
no write access to the source tree.
-
* Provide convenience aliases for target architecture names.
-
- * Make the default be offline (ie, not to access the internet)
+ * Make the default be offline (ie, not to access the internet).
These functions are of course configurable.
myproject
mylibrary
"""
-$ nailing-cargo cargo generate-lockfile
-$ nailing-cargo cargo build
+$ nailing-cargo -u fetch
+$ nailing-cargo build
```
+Documentation table of contents
+-------------------------------
+
+<!-- TOC autogenerated by ./markdown-toc-filter, do not edit -->
+
+ * [Introduction](#nailing-cargo)
+ * [Installing](#installing)
+ * [Most basic example usage](#most-basic-example-usage)
+ * [Documentation table of contents](#documentation-table-of-contents)
+ * [Using local crates, or locally modified crates](#using-local-crates-or-locally-modified-crates)
+ * [How nailing-cargo helps with using local crates](#how-nailing-cargo-helps-with-using-local-crates)
+ * [Telling nailing-cargo how to massage `Cargo.toml`](#telling-nailing-cargo-how-to-massage-cargo.toml)
+ * [Out-of-tree builds](#out-of-tree-builds)
+ * [How nailing-cargo helps with out-of-tree builds](#how-nailing-cargo-helps-with-out-of-tree-builds)
+ * [Configuring out-of-tree builds](#configuring-out-of-tree-builds)
+ * [Target architecture convenience aliases](#target-architecture-convenience-aliases)
+ * [Default change to offline mode](#default-change-to-offline-mode)
+ * [Invocation and command-line option reference](#invocation-and-command-line-option-reference)
+ * [Usages](#usages)
+ * [Options](#options)
+ * [Environment of the build command](#environment-of-the-build-command)
+ * [Configuration reference](#configuration-reference)
+ * [Source directories and packages (toplevel)](#source-directories-and-packages-toplevel)
+ * [`[alt_cargolock]`: Alternative `Cargo.lock` filename](#alt_cargolock-alternative-cargo.lock-filename)
+ * [`[oot]`: Out-of-tree build support](#oot-out-of-tree-build-support)
+ * [`[arch]`: Architecture convenience aliases](#arch-architecture-convenience-aliases)
+ * [`[misc]`: Miscellaneous individual nailing-cargo config](#misc-miscellaneous-individual-nailing-cargo-config)
+ * [Limitations and bugs](#limitations-and-bugs)
+ * [Contributing and legal](#contributing-and-legal)
+ * [Legal](#legal)
+
Using local crates, or locally modified crates
==============================================
Telling nailing-cargo how to massage `Cargo.toml`
-------------------------------------------------
-To find the subdirectories, and the packages, it looks for `subdirs`
-and `packages` in `Cargo.nail`.
+To find the subdirectories, and the packages, nailing-cargo looks for
+`subdirs` and `packages` in `Cargo.nail`.
+
+For straightforward use, write `subdirs` as a multi-line string
+containing a list of subdirectory names one per line. In each of
+these directories `Cargo.toml` will be massaged, and the package there
+will be used for other massaged `Cargo.toml`s.
+
+See the [Configuration reference](#configuration-reference) for full details.
+
+Scope of nailing-cargo's local crate functionality
+--------------------------------------------------
+
+nailing-cargo's `Cargo.toml` massaging will allow you to easily build
+an interdepending set of local packages, possibly even including
+private unpublished packages, and/or locally-modified versions of
+published packages. These local packages can freely depend on
+published packages (eg from `crates.io`) in the usual way.
-`subdirs` can be a (usually multi-line) string containing a list of
-subdirectory names one per line. (`#`-comments are supported.) Or it
-can be a list of strings (`subdirs = ['myproject','mylibrary']`). In
-each of these directories `Cargo.toml` will be massaged, and
-the package there will be used for other massaged `Cargo.toml`s
+Compared to the corresponding cargo feature, nailing-cargo's approach:
+(i) works even for local crates that have not been published anywhere; and
+(ii) is a lot simpler to configure.
-For more complex cases: `packages` is a mapping from package names to
-strings or dictionaries (e.g. in `Cargo.nail`, write something like:
-`[packages.mylibrary]` `subdir='mylibrary-test'` or `[packages]`
-`mylibrary='mylibrary-test'`). These override the locations for the
-specified packages (so you can, for example, have multiple trees with
-the same package in). These subdirectories are also added to the list
-of places where `Cargo.toml` should be massaged.
+But nailing-cargo's local crate support won't work if any non-local
+crate needs to be rebuilt against a local crate (ie, a local version
+of one of its dependencies). If that is your requirement, either make
+local versions of the intermediate crates in the dependency graph, or
+use the cargo override facility --- see [Overriding
+Dependencies](https://doc.rust-lang.org/cargo/reference/overriding-dependencies.html)
+in the Cargo Book.
Out-of-tree builds
==================
`.gitignore`; or commit it to git; or you can tell nailing-cargo to
save it as something like `Cargo.lock.example`.
+Depending on the circumstances, nailing-cargo uses a variety of
+strategies, including `--manifest-path` options, and linkfarming, to
+make out of tree builds. Some crates don't natively support
+out-of-tree builds, in which case passing a `--linkfarm` option to
+nailing-cargo can be helpful.
+
Configuring out-of-tree builds
------------------------------
`Cargo.nail` or one of nailing-cargo's other config files.
In that section, specify at least `use`.
-The primary config keys here are:
+Also, specify `dir`, or create a symlink `Build` next to `Cargo.nail`,
+pointing to to your build area.
- * `dir`: The build directory. If relative, it is relative to the
- parent of the invocation directory (and could be a symlink then).
- Default is `Build` (assuming `use` is specified).
-
- * `use`: How to become the build user. Needs to be combined
- with other setting(s):
-
- * `ssh`: Use ssh. `user` must be given as well and can be
- a username on localhost, or the `<user>@<host>`
- argument to ssh.
-
- * `command_args`: `command` must be specified as a list,
- specifying a command and arguments which work like `nice`.
-
- * `command_sh`: `command` must be specified as a list,
- specifying a command and arguments which work like `sh -c`.
-
- * `null`: Run builds as the same user.
-
- * `really`: Use `really` from `chiark-really.deb`.
- `user` must be given as well.
+For example,
+```
+[oot]
+use='ssh'
+user='rustcargo'
+```
+will have nailing-cargo run `ssh rustcargo@localhost` to
+run build commands.
Target architecture convenience aliases
=======================================
`--target=` when it thinks it's not needed.
In your nailing-cargo config, you can write something like
-`arch.RPI='arm-unknown-linux-gnueabihf'`. Then `nailing-cargo -ARPI`
+`arch.RPI='arm-unknown-linux-gnueabihf'`. Then `nailing-cargo -TRPI`
will DTRT. In fact, you do not even need to specify that particular
arch alias, since it is built-in to nailing-cargo.
nailing-cargo configuration. `misc.online=false`, and command line
options, are also available, for overriding.
-Command-line options
-====================
+If you agree with me, you may wish to use `nailing-cargo
+generate-lockfile`, which can update (even an existing) `Cargo.lock`
+without going online, instead of `update`.
+
+Invocation and command-line option reference
+============================================
+
+Usages
+------
+
+```
+1$ nailing-cargo <nailing-opts> <cargo-opts> [--] <subcmd>...
+2$ nailing-cargo <nailing-opts> --- <cargo> <cargo-opts> [--] <subcmd>...
+3$ nailing-cargo <nailing-opts> --- [--] <build-command>...
+```
+Ususally the `--` is not needed. (It should generally be passed by
+programs which wrap nailing-cargo. See [Invocation argument disambiguation rules](#invocation-argument-disambiguation-rules), below.)
+
+In usage 1, nailing-cargo runs `cargo` (from `PATH`). In the usage 2
+nailing-cargo runs `<cargo>`. In both these cases it adds its own
+options to control cargo's behaviour. In both of these cases
+nailing-cargo looks at `<subcmd>` to determine the cargo subcommand
+being run: this controls various defaults, to try to do the right
+things.
+
+In the third syntax, nailing-cargo runs `<build-command>...` without
+additional arguments and does not attempt to identify the cargo
+subcommand(s) that it will run. Possibly it will be necessary to pass
+`--online` or `--cargo-lock-update`, or even `--cargo-*arg*`
+
+### Invocation argument disambiguation rules ###
+
+For authors of tools which call nailing-cargo (and pedants):
+
+The usages overlap in syntax! nailing-cargo follows the following
+rules when interpreting its command line:
+
+ * The first option not recognised as a nailing-cargo option is
+ treated as the start of the `<cargo-opts>`.
+
+ * `<cargo-opts>` are terminated by `--` (which is removed) or the
+ first argument which does not start with a `-` or `+`.
+
+ (It is not possible to get nailing-cargo to pass the value `--`
+ as a separate argument to a cargo global option, but cargo global
+ options can typically take the values cuddled with `=`, so doing
+ that is not necessary.)
+
+ * After `---`, nailing-cargo will search for a `--`, to the end of
+ the arguments if necessary. The position of the `--` determines
+ whether this is usage 2 or usage 3, and what `<subcmd>` is.
+
+ If the arguments after `nailing-cargo ... ---` might contain `--`
+ anywhere, an explicit `--` should be passed.
+
+ * If no `--` appears after `---`, the word after `---` is the
+ command to run; if its final pathname component contains the
+ string `cargo`, it is treated as `<cargo>` (implying usage 2 and
+ the search for `<subcmd>`). Otherwise it is treated as
+ `<build-command>` (usage 3).
+
+Options
+-------
* `-v`: Increase verbosity. Default is 1.
* `-n`: "No action": stop after writing `Cargo.toml.nailing~`
everywhere, and do not run any build command.
- * `-A<arch>` | `--arch=<arch>` | `--target=<arch>`
+ * `-T<arch>` | `--target=<arch>`
- Specify target architecture.
+ Specify target architecture.
- This option translates to a `--target=<arch>` option to the
- ultimate command, unless that is a cargo subcommand which we
- know would reject it. `--arch` and `--target` are simply
- aliases.
+ This option translates to a `--target=<arch>` option to cargo
+ (when the subcommand accepts it).
- If `<arch>` starts with a capital ascii letter, it is an alias
- for some other arch: it is looked up in the configuration, and
- then in the builtin arch alias list. The builtin list is
- equivalent to: `[arch]` `RPI='arm-unknown-linux-gnueabihf'`.
+ If `<arch>` starts with a capital ascii letter, it is an alias
+ for some other arch: it is looked up in the configuration, and
+ then in the builtin arch alias list. The builtin list is
+ equivalent to:
- * `-u` | `--cargo-lock-update` | `-U` | `--no-cargo-lock-update`
-
- Enables, or disables, the dance to allow `Cargo.lock` (or
- alternative) to be updated in the source directory.
-
- With this dance enabled the `Cargo.lock` and `Cargo.toml` are
- copied to the build directory along with a skeleton just big
- enough to fool cargo. After cargo has run, the resulting
- `Cargo.lock` is copied back to the source tree.
+```
+[arch]
+RPI="arm-unknown-linux-gnueabihf"
+WASM="wasm32-unknown-unknown"
+```
- This makes no sense with in-tree builds.
+ * `-o` | `--online` | `-O` | `--offline`
- Default is no update unless the ultimate command is a
- cargo subcommand which we know needs it.
+ Whether to allow cargo to make network access. nailing-cargo
+ always passes `--offline` to cargo, unless `--online` is in
+ force. The default value depends on the configuration and the
+ cargo subcommand - see [`[misc]` `online`](#misc_online),
+ under Configuration.
- * `-m` | `--cargo-manifest-args` | `-M` | `--no-cargo-manifest-args`
+ * `-u` | `--cargo-lock-update` | `-U` | `--no-cargo-lock-update`
- Controls whether we add cargo command line options, relating to
- finding `Cargo.toml`, to the command to run.
+ Allows (or disallows) cargo to update `Cargo.lock` in the source
+ directory. Without this enabled, nailing-cargo passes `--locked`
+ to cargo.
+
+ With this enabled, in an out-of-tree build the `Cargo.lock` and
+ `Cargo.toml` are copied to the build directory along with a
+ linkfarm, to fool cargo. After cargo has run, the resulting
+ `Cargo.lock` is copied back to the source tree.
+
+ Default is no update unless the whole point of the cargo
+ subcommand is to update `Cargo.lock`.
+
+ * `-c` | `-C`
+
+ Controls the addition of cargo command line options; ie,
+ whether nailing-cargo should treat the build command as if it
+ were cargo.
+ With `-C`, nailing-cargo will not add additional options
+ to the build command. With `-c` it will pass those options
+ after the cargo subcommand (usages 1 and 2) or right
+ after the build command (usage 3).
+
+ The cargo options are in any case also passed in the
+ environment - see [Environment of the build command](#environment-of-the-build-command).
+
+ The default is to pass cargo options if the command line
+ parsing yielded a cargo command and options (usages 1 and 2),
+ rather than a non-cargo build command (usage 3). `-C` and `-c`
+ do not affect the parsing of nailing-cargo's command line.
+
+ * <a name="s_subcommand">`-s<subcommand>`</a>
+
+ Behave as if the build command were `cargo <subcommand>`.
+ This influences the logic which tries to determine which
+ options to pass to cargo, whether cargo needs to be online, and
+ whether cargo might want to update `Cargo.lock`.
+
+ nailing-cargo knows about the following commands:
+ * `fetch`
+ * `fmt`
+ * `generate-lockfile`
+ * `update`
+
+ All other subcommands are (silently) treated the same way
+ as `build` (ie, no subcommand properties). See
+ `--subcommand-props` for more detail about how the
+ subcommand affects nailing-cargo's behaviour.
+
+ The default is to use the cargo subcommand found from parsing
+ nailing-cargo's command line. NB: `-s` does not affect
+ which build command (and which cargo subcommand) is actually run.
+
+ * <a name="subcommand_props">`--subcommand-props=<prop>,...`</a>
+
+ Specify the properties of the subcommand. This is an
+ alternative to `-s<subcmd>`. The usual properties are:
+
+ * `lock_update`: cargo will want to update `Cargo.lock`. (The `-u` and `-U` options override this.)
+ * `online`: this subcommand makes no sense to run offline. (The `-o` and `-O` options, and the configuration, can override this.)
+ * `edits`: The purpose of this subcommand is to edit the source tree. Produces warning if `--edit-sources` mode not specified.
+ * `!target`: cargo would reject `--target=<arch>`; in this case nailing-cargo's `-T` option is ineffective.
+ * `!target-dir`: cargo would reject `--target-dir`, so don't pass it. (Usually we pass `--target-dir=target` when we pass `--manifest-path`, since cargo's default is `target` in the same directory as `Cargo.toml`.)
+ * `linkfarm-shallow`: Make the default be `--linkfarm=shallow`. This is the default for `miri` and can also be used for other subcommands which do not understandg `--manifest-path` properly.
+ * `linkfarm-gitclean`: Make the defaults be `--linkfarm=git` and `--preclean-build=src`.
+
+ There are also some properties which should not be needed, but are
+ provided for completeness. Do not use these to solve the problem
+ of nailing-cargo passing cargo options to a build command which is
+ not cargo - use `-C` for that. The properties whose use is discouraged:
+
+ * `!manifest-path`: cargo would reject `--manifest-path`, so don't pass it (and don't pass `--target-dir` either). Only makes any difference for out-of-tree builds. Things will probably go wrong unless the build command looks at `[NAILING]CARGO_MANIFEST_DIR`.
+ * `!locked`: cargo would reject `--locked`, so don't pass it. Hazardous.
+ * `!offline`: the build command would reject `--offline`, so never pass it. *Not* overridden by configuration or command line.
+
+
+ * `--linkfarm[=no|shallow|git|full]`: Override nailing-cargo's
+ approach to out-of-tree builds. Normally nailing-cargo chooses
+ automatically whether to make a linkfarm, and precisely what kind
+ of linkfarm, based on the cargo subcommand. The linkfarm styles
+ are:
+
+ * `no`: Do not make a linkfarm; pass a `--manifest-path` option
+ pointing to the actual source directory. This is the default
+ for most cargo commands.
+
+ * `shallow`: Symlink top-level objects in the source directory,
+ including whole subdirectories. This the default when
+ nailing-cargo thinks cargo is going to update `Cargo.lock`.
+
+ * `git`: Make a deep linkfarm, with subdirectories. Symlink
+ those objects tracked by git. This is the default for
+ `cargo publish`.
+
+ * `full`: Make a deep linkfarm and symlink every nondirectory found
+ in the source tree. This will including all sorts of junk,
+ including for example editor backup files.
+
+ Whenever nailing-cargo linkfarms, old symlinks pointing back to
+ the source tree are deleted. In each case, `Cargo.lock` is not
+ symlinked, but copied. If nailing-cargo expects cargo to update
+ `Cargo.lock`, it will copy it back to the source tree afterwards.
+ Just `--linkfarm` is the same as `--linkfarm=git`.
+
+ * `--edit | --edit-sources | -E`: Permits the cargo command to edit
+ sources in the source tree. This is achieved by *copying* the
+ entire source tree (all files tracked by git) into the destination
+ directory, and then copying back all changed files. *Only git
+ tracked filles* can be edited by the cargo command; edits to
+ other files, and creation of new files, will be ignored.
+
+ If you are running out of tree builds for privsep reasons, you
+ should use git to review the edits made by the cargo command and
+ either stage and commit them, or reject them.
+
+ This is the default mode for `nailing-cargo fmt`.
+
+ * `--just-linkfarm[=shallow|git|full]`: Make the out-of-tree
+ linkfarm as if for `--cargo-lock-update`, but do not actually run
+ any command, nor try to copy back a a generated `Cargo.lock`.
+ Forces `--keep-linkfarm` (even if the contrary is also specified).
+
+ With a linkfarming mode, overrides (and is overridden by)
+ `--linkfarm=`. Without a linkfarming mode, and without
+ `--linkfarm`, the default is `shallow`.
+
+ * `--keep-linkfarm` | `--clean-linkfarm`: When doing an out-of-tree
+ lockfile update, controls whether the linkfarm is kept afterwards.
+ Overrides the `oot.clean` config option. (Default: keep.)
+
+ * `--[no-]preclean-build[=no|src|full]`: When doing an out-of-tree
+ build, controls whether the build directory is purged of leftover
+ contents *before* the build is run. The usual default is `no`.
+ For `cargo publish`, the default is `src`, which deletes
+ everything except the directory `target`. `full` means to clean
+ out that too.
+
+ * `--leave-nailed`: At the end, leave all the `Cargo.toml` files in
+ their edited state, rather than (trying to) clean them up. To
+ clean this up later, run `nailing-cargo` again without this option.
+ Without this option, the nailed versions are left in
+ `.Cargo.toml.nailed~`, so you only need this if you want to run
+ cargo by hand or something.
+
+ * `--just-run`: Execute the specified command (perhaps concurrently
+ with other commands), but do not manipulate any of Cargo's
+ metadata fiules. Useful in out of tree mode to invoke a non-cargo
+ command in the build environment. Implies `--no-nail`,
+ `--no-cargo-lock-manip` and `--no-concurrency-lock` (overrideable
+ by later occurrences of the corresponding opposite options).
+ Hazardous if the command is actually cargo, or will run cargo.
+
+ * `--no-nail` | `--nail` (default): Whether to actually nail - ie,
+ whether to actually modify any `Cargo.toml`s while running the
+ command. This can be useful, e.g., in out-of-tree mode with
+ commands that don't actually invoke cargo. Consider passingm
+ `--no-lock` too.
+
+ * `--no-cargo-lock-manip` | `--cargo-lock-manip` (default):
+ Whether to manipulate `Cargo.lock`. For example, whether to copy
+ it to the build tree and back (in out of tree mode) and whether to
+ rename it from an alternative lockfile name, and put it back.
+ Overrides `-u` etc.
+
+ * `--no-concurrency-lock` | `--concurrency-lock` (default): Whether
+ to take the nailing-cargo lock. Some kind of protection against
+ concurrent operation is necessary to prevent multiple instances of
+ nailing-cargo trashing each others' work, and possibly mangling
+ your `Cargo.toml`s, `Cargo.lock`, etc., so `--no-concurrency-lock`
+ is dangerous unless you take other measures against concurrent
+ execution.
+
+ * `-h` | `--help`: Print usage summary.
+
+ * `--doc` | `--man` | `--manual`: Format this manual into html using
+ `pandoc` and display it with `w3m`.
+
+Environment of the build command
+--------------------------------
- Default is to add them if we are doing an out-of-tree build,
- unless we are doing the dance to update the `Cargo.lock` (see
- above) since in that case all the relevant files can be found
- by cargo in the build directory.
+nailing-cargo passes these environment variables to the build command:
- The arguments added are
+ * `CARGO_MANIFEST_DIR`: invocation `.` (invocation directory)
+ * `NAILINGCARGO_MANIFEST_DIR`: same as `CARGO_MANIFEST_DIR`
+ * `NAILINGCARGO_WORKSPHERE`: invocation `..` (parent)
+ * `NAILINGCARGO_BUILD_DIR`: build directory (even if same as source)
+ * `NAILINGCARGO_BUILDSPHERE`: parent of build dir (only set if out-of-tree)
+ * `NAILINGCARGO_CARGO_OPTIONS`: additional options that nailing-cargo passed (or would pass) to cargo. Space-separated; does not include `--manifest-path`.
- --manifest-path=<path/to/Cargo.toml>
- --locked
- --target-dir=target
+All of these are absolute paths.
- * `-T` | `--no-cargo-target-dir-arg` | `-t` | `--cargo-target-dir-arg`
+### Build commands which wrap cargo ###
- `-T` suppresses `--target-dir`; `-t` un-suppresses it. Only
- makes any difference with `-m`, since otherwise no
- `--target-dir` would be passed anyway. Additionally this is
- done automatically when nailing-cargo sees that the cargo
- subcommand is one which needs it, eg `fetch`.
+If you specify a build command which eventually runs cargo, you may
+wish to pass on to your cargo the options which nailing-cargo would
+have passed. This will definitely be necessary if you are using nailing-cargo's out-of-tree facility.
- * `-o` | `--online` | `-O` | `--offline`
+In such a situation, do it like this:
+```
+ cargo build --manifest-path="${CARGO_MANIFEST_DIR-.}"/Cargo.toml $NAILINGCARGO_CARGO_OPTIONS
+```
- Whether to allow cargo to make network access. nailing-cargo
- always passes `--offline` to cargo, unless `--online` is in
- force. The default is offline, unless the cargo subcommand is
- one which implies online (currently, `fetch`).
+If you need to run a cargo subcommand which doesn't understand some of
+nailing-cargo's options, currently, you must strip them out of
+`NAILINGCARGO_CARGO_OPTIONS` yourself - or pass some `-s` or
+`--subcmd-props` option to nailing-cargo (but that is a layering
+violation and may not work if one build command runs various different
+cargo runes).
-Configuration
-=============
+Configuration reference
+=======================
nailing-cargo reads these configuration files:
```
Settings in later-mentioned files override ones in earlier-mentioned
files.
-Note that unlike everything else, `packages` and `subdirs` are read
-only from `Cargo.nail` (see "Limitations and bugs", below).
+Source directories and packages (toplevel)
+------------------------------------------
+
+Note that unlike everything else, these keys (`packages` and
+`subdirs`) are read only from `Cargo.nail` (see "Limitations and
+bugs", below).
+
+These keys specify a combination of (i) a mapping from package name to
+source subdirectory (ii) a set of subdirectories whose `Cargo.toml`
+must be massaged.
+
+ * `packages`: a map keyed by package name, giving the subdirectory
+ for each one.
+
+ This causes each mentioned subdirectory's `Cargo.toml` to be
+ massaged, and records that subdirectory as the source for that
+ package. (nailing-cargo will check that subdirectory actually
+ contains the indicated package.)
+
+ Each value can be just the subdirectory name (eg `[packages]`
+ `mylibrary='mylibrary-test'`) or itself a map with the key `subdir`
+ (eg `[packages.mylibrary]` `subdir='mylibrary-test'`).
+
+ * `subdirs`: a list of subdirectory names to process.
+
+ Each subdirectory's `Cargo.toml` will be massaged. Also, the
+ subdirectory will be examined to see what package it contains; it
+ will then be used as the source for that package, unless that
+ package appears in an entry in `packages`, or an earlier entry in
+ `subdirs`.
-Alternative `Cargo.lock` filename
----------------------------------
+ This can be a list of strings (eg `subdirs =
+ ['myproject','mylibrary']`). Or it can be single multi-line
+ string containing one subdirectory name per line; in that
+ case, `#`-comments are supported and tabs and spaces are ignored
+ (see "Most basic example usage" above.)
+
+In each case the subdirectory should usually be a relative pathname;
+it is relative to the directory containing `Cargo.nail`.
+
+`[alt_cargolock]`: Alternative `Cargo.lock` filename
+----------------------------------------------------
To control use of alternative `Cargo.lock` filename, use the section
`[alt_cargolock]`. Settings here:
* `force = true`: Always uses the alternative filename.
-Running the command
-===================
+`[oot]`: Out-of-tree build support
+----------------------------------
-Normally you pass cargo as an argument to nailing-cargo. But you
-can also pass make or any other command. You may need to pass
-`--no-cargo-manifest-args` (aka `-M`) to nailing-cargo, to avoid
-passing options like `--manifest-path` to make or whatever.
+ * `dir`: The build directory. If relative, it is relative to the
+ parent of the invocation directory (and could be a symlink then).
+ Default is `Build` (assuming `use` is specified).
-nailing-cargo passes these environment variables to the build command:
+ The build directory will contain one subdir for each package: each
+ subdir in the build dir corresponds to one source dir where
+ nailing-cargo was invoked. nailing-cargo will arrange to create
+ these subdirectories, so the build directory can start out empty.
- * `NAILINGCARGO_WORKSPHERE`: invocation `..` (parent)
- * `NAILINGCARGO_MANIFEST_DIR`: invocation `.` (invocation directory)
- * `NAILINGCARGO_BUILD_DIR`: build directory (even if same as source)
- * `NAILINGCARGO_BUILDSPHERE`: only set if out of tree: parent of build dir.
+ * `use`: How to become the build user. Needs to be combined
+ with other setting(s):
-All of these are absolute paths.
+ * `ssh`: Use ssh. `user` must be given as well and can be
+ a username on localhost, or the `<user>@<host>`
+ argument to ssh.
+
+ * `command_args`: `command` must be specified as a list,
+ specifying a command and arguments which work like `nice`.
+
+ * `command_sh`: `command` must be specified as a list,
+ specifying a command and arguments which work like `sh -c`.
+
+ * `null`: Run builds as the same user.
+
+ * `really`: Use `really` from `chiark-really.deb`.
+ `user` must be given as well.
+
+ * `disable': Disable this feature, even if `dir` is set.
+
+ * `command`: The command to run for `command_sh` or `command_args`.
+
+ In both cases, this is a command and its arguments/options. The
+ list will be passed to `execvp`. The difference between
+ `command_args` and `command_sh` is in what nailing-cargo appends to
+ the specified `command` list:
+
+ For `command_args`, nailing cargo appends multiple more arguments;
+ each one should be passed as-is as a single argument to the actual
+ build command. This is correct if `command` is a program like
+ `nice` or `really`, which takes a command and its arguments and
+ does not go via the shell.
+
+ For `command_sh`, nailing-cargo appends one single further
+ argument. That argument is a shell command; nailing-cargo
+ constructs it by shell-quoting the real command and arguments and
+ wrapping them up in a small script, the text of which becomes the
+ extra argument to `command`. This is correct if `command` will
+ pass its argument to a bournelike shell - for example, if `command`
+ is an ssh rune for a remote account whose shell is `/bin/sh` or
+ `/bin/bash`.
+
+ * `user`: The build username, for `really` and `ssh`. For `ssh`, can
+ be just the local username (meaning `@localhost`), or
+ `<user>@<host>`.
+
+ * `clean` (boolean): When doing a `Cargo.lock` update, which involves
+ linkfarming in the build directory, whether the clean up the
+ linkfarm afterwards. Default: `true`. Can be overridden by
+ `--keep-linkfarm` or `--clean-linkfarm`.
+
+`[arch]`: Architecture convenience aliases
+------------------------------------------
+
+This is a map from archictecture aliases to full cargo architecture
+names. The keys are the aliases; each entry should be a string, the
+cargo architecture name.
+
+Only keys starting with an ascii uppercase letter are relevant, since
+other names are not looked up in this alias map.
+
+`[misc]`: Miscellaneous individual nailing-cargo config
+-------------------------------------------------------
+
+ * <a name="misc_online">`online`</a>:
+
+ Specifies whether to allow or prevent cargo from accessing the
+ network. Value is a boolean or `'auto'`. `'auto'` permits online
+ access if the cargo subcommand being invoked is one whose main
+ purpose involves online access.
+
+ Implemented by passing `--offline` to cargo when necessary ---
+ cargo's default is online. nailing-cargo's default is
+ `'auto'`.
Limitations and bugs
====================
At least, running nailing-cargo again will clean up any mess
left by an interrupted run.
- * Out of tree builds require a unified filesystem view: eg, different
+ * nailing-cargo needs to understand the behaviour of the cargo
+ subcommand you are running - especially for out-of-tree builds.
+ nailing-cargo only has a short builtin list of commands it knows
+ about (see [`-s<subcommand`](#s_subcommand)). For other commands, you may need to
+ add an entry to `@subcmd_props` in the source, or use
+ [`--subcommand-props`](#subcommand_props).
+
+ Contributions of additonal entries to `@subcmd_props` (or bug
+ reports about missing entries) are of course very welcome.
+
+ * Out-of-tree builds ought to support `sudo`. Patches welcome.
+
+ * Out-of-tree builds require a unified filesystem view: eg, different
users on the same host, NFS, or something.
Specifically, the invocation and build execution environments must