From d5fa7b8a557ca0b0ca272cf82c66c2cc2e940f39 Mon Sep 17 00:00:00 2001
From: Reilly Wood <26268125+rgwood@users.noreply.github.com>
Date: Wed, 9 Aug 2023 22:36:09 -0700
Subject: [PATCH] Put heavy dataframe dependencies behind feature flag (#9971)

Context from Discord:
https://discord.com/channels/601130461678272522/615962413203718156/1138694933545504819

I was working on Nu for the first time in a while and I noticed that
sometimes rust-analyzer takes a really long time to run `cargo check` on
the entire workspace. I dug in and it was checking a bunch of
dataframe-related dependencies even though the `dataframe` feature is
not built by default.

It looks like this is a regression of sorts, introduced by
https://github.com/nushell/nushell/pull/9241. Thankfully the fix is
pretty easy, we can make it so everything important in
`nu-cmd-dataframe` is only used when the `dataframe` feature is enabled.

### Impact on `cargo check --workspace`

Before this PR: 635 crates, 33.59s
After this PR: 498 crates, ~20s

(with the `mold` linker and a `cargo clean` before each run, the
relative difference for incremental checks will likely be much larger)
---
 crates/nu-cmd-dataframe/Cargo.toml | 4 ++--
 crates/nu-cmd-dataframe/src/lib.rs | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/crates/nu-cmd-dataframe/Cargo.toml b/crates/nu-cmd-dataframe/Cargo.toml
index 83a29e8c5..e4f20cbb4 100644
--- a/crates/nu-cmd-dataframe/Cargo.toml
+++ b/crates/nu-cmd-dataframe/Cargo.toml
@@ -56,8 +56,8 @@ optional = true
 version = "0.30.0"
 
 [features]
-dataframe = ["default"]
-default = ["num", "polars", "sqlparser"]
+dataframe = ["num", "polars", "sqlparser"]
+default = []
 
 [dev-dependencies]
 nu-cmd-lang = { path = "../nu-cmd-lang", version = "0.83.2" }
diff --git a/crates/nu-cmd-dataframe/src/lib.rs b/crates/nu-cmd-dataframe/src/lib.rs
index f84027aca..7e7c8014c 100644
--- a/crates/nu-cmd-dataframe/src/lib.rs
+++ b/crates/nu-cmd-dataframe/src/lib.rs
@@ -1,2 +1,4 @@
+#[cfg(feature = "dataframe")]
 pub mod dataframe;
+#[cfg(feature = "dataframe")]
 pub use dataframe::*;