add workspace_hack crate

Our builds can be a little inconsistent, because Cargo doesn't deal well
with workspaces where there are multiple crates which have different
dependencies that select different features. As a workaround, copy what
other big rust projects do: add a workspace_hack crate.

This crate just pins down a set of dependencies and features that
satisfies all of the workspace crates.

The benefits are:
- running `cargo build` from one of the workspace subdirectories now
  works without rebuilding anything.
- running `cargo install` works (without rebuilding anything).
- making small dependency changes is much less likely to trigger large
  dependency rebuilds.

Cargo.lock

@@ -269,6 +269,7 @@ dependencies = [
  "tokio-postgres",
  "toml",
  "walkeeper",
+ "workspace_hack",
 ]
 
 [[package]]
@@ -1180,6 +1181,7 @@ dependencies = [
  "tokio-stream",
  "tui",
  "walkdir",
+ "workspace_hack",
  "zenith_utils",
 ]
 
@@ -1342,6 +1344,7 @@ dependencies = [
  "rand",
  "regex",
  "thiserror",
+ "workspace_hack",
 ]
 
 [[package]]
@@ -2238,6 +2241,7 @@ dependencies = [
  "tokio-postgres",
  "tokio-stream",
  "walkdir",
+ "workspace_hack",
 ]
 
 [[package]]
@@ -2389,6 +2393,22 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "workspace_hack"
+version = "0.1.0"
+dependencies = [
+ "libc",
+ "memchr",
+ "num-integer",
+ "num-traits",
+ "proc-macro2",
+ "quote",
+ "regex",
+ "regex-syntax",
+ "serde",
+ "syn",
+]
+
 [[package]]
 name = "xattr"
 version = "0.2.2"
@@ -2413,6 +2433,7 @@ dependencies = [
  "control_plane",
  "pageserver",
  "postgres_ffi",
+ "workspace_hack",
 ]
 
 [[package]]

Cargo.toml

@@ -7,4 +7,5 @@ members = [
     "control_plane",
     "postgres_ffi",
     "zenith_utils",
+    "workspace_hack",
 ]

control_plane/Cargo.toml

@@ -25,3 +25,4 @@ thiserror = "1"
 pageserver = { path = "../pageserver" }
 walkeeper = { path = "../walkeeper" }
 postgres_ffi = { path = "../postgres_ffi" }
+workspace_hack = { path = "../workspace_hack" }

pageserver/Cargo.toml

@@ -42,3 +42,4 @@ parse_duration = "2.1.1"
 
 postgres_ffi = { path = "../postgres_ffi" }
 zenith_utils = { path = "../zenith_utils" }
+workspace_hack = { path = "../workspace_hack" }

postgres_ffi/Cargo.toml

@@ -17,6 +17,7 @@ crc32c = "0.6.0"
 hex = "0.4.3"
 log = "0.4.14"
 thiserror = "1.0"
+workspace_hack = { path = "../workspace_hack" }
 
 [build-dependencies]
 bindgen = "0.57"

walkeeper/Cargo.toml

@@ -34,3 +34,4 @@ walkdir = "2"
 # FIXME: 'pageserver' is needed for ZTimelineId. Refactor
 pageserver = { path = "../pageserver" }
 postgres_ffi = { path = "../postgres_ffi" }
+workspace_hack = { path = "../workspace_hack" }

workspace_hack/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "workspace_hack"
+version = "0.1.0"
+edition = "2018"
+
+[target.'cfg(all())'.dependencies]
+libc = { version = "0.2", features = ["default", "extra_traits", "std"] }
+memchr = { version = "2", features = ["default", "std", "use_std"] }
+num-integer = { version = "0.1", default-features = false, features = ["std"] }
+num-traits = { version = "0.2", default-features = false, features = ["std"] }
+regex = { version = "1", features = ["aho-corasick", "default", "memchr", "perf", "perf-cache", "perf-dfa", "perf-inline", "perf-literal", "std", "unicode", "unicode-age", "unicode-bool", "unicode-case", "unicode-gencat", "unicode-perl", "unicode-script", "unicode-segment"] }
+regex-syntax = { version = "0.6", features = ["default", "unicode", "unicode-age", "unicode-bool", "unicode-case", "unicode-gencat", "unicode-perl", "unicode-script", "unicode-segment"] }
+serde = { version = "1", features = ["default", "derive", "serde_derive", "std"] }
+
+[target.'cfg(all())'.build-dependencies]
+libc = { version = "0.2", features = ["default", "extra_traits", "std"] }
+memchr = { version = "2", features = ["default", "std", "use_std"] }
+proc-macro2 = { version = "1", features = ["default", "proc-macro"] }
+quote = { version = "1", features = ["default", "proc-macro"] }
+regex = { version = "1", features = ["aho-corasick", "default", "memchr", "perf", "perf-cache", "perf-dfa", "perf-inline", "perf-literal", "std", "unicode", "unicode-age", "unicode-bool", "unicode-case", "unicode-gencat", "unicode-perl", "unicode-script", "unicode-segment"] }
+regex-syntax = { version = "0.6", features = ["default", "unicode", "unicode-age", "unicode-bool", "unicode-case", "unicode-gencat", "unicode-perl", "unicode-script", "unicode-segment"] }
+syn = { version = "1", features = ["clone-impls", "default", "derive", "full", "parsing", "printing", "proc-macro", "quote", "visit", "visit-mut"] }

workspace_hack/src/lib.rs

@@ -0,0 +1,23 @@
+//! This crate contains no code.
+//!
+//! The workspace_hack crate exists only to pin down some dependencies,
+//! so that those dependencies always build with the same features,
+//! under a few different cases that can be problematic:
+//! - Running `cargo check` or `cargo build` from a crate sub-directory
+//!   instead of the workspace root.
+//! - Running `cargo install`, which can only be done per-crate
+//!
+//! The dependency lists in Cargo.toml were automatically generated by
+//! a tool called
+//! [Hakari](https://github.com/facebookincubator/cargo-guppy/tree/main/tools/hakari).
+//!
+//! Hakari doesn't have a CLI yet; in the meantime the example code in
+//! their `README` file is enough to regenerate the dependencies.
+//! Hakari's output was pasted into Cargo.toml, except for the
+//! following manual edits:
+//! - `winapi` dependency was removed. This is probably just due to the
+//!   fact that Hakari's target analysis is incomplete.
+//!
+//! There isn't any penalty to this data falling out of date; it just
+//! means that under the conditions above Cargo will rebuild more
+//! packages than strictly necessary.

zenith/Cargo.toml

@@ -14,3 +14,4 @@ anyhow = "1.0"
 pageserver = { path = "../pageserver" }
 control_plane = { path = "../control_plane" }
 postgres_ffi = { path = "../postgres_ffi" }
+workspace_hack = { path = "../workspace_hack" }