add snapshot test suitesnapshot-tests

31 files changed, 489 insertions, 20 deletions

diff --git a/bin/Cargo.toml b/bin/Cargo.toml
index d67e6c1..7c48083 100644
--- a/bin/Cargo.toml
+++ b/bin/Cargo.toml
@@ -6,7 +6,13 @@ license = "MIT"
 authors = [ "Akshay <[email protected]>" ]
 description = "Lints and suggestions for the Nix programming language"
 
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+[lib]
+name = "statix"
+path = "src/lib.rs"
+
+[[bin]]
+name = "statix"
+path = "src/main.rs"
 
 [dependencies]
 ariadne = "0.1.3"
@@ -27,5 +33,9 @@ version = "1.0.68"
 features = [ "derive" ]
 optional = true
 
+[dev-dependencies]
+insta = "1.8.0"
+strip-ansi-escapes = "0.1.1"
+
 [features]
 json = [ "lib/json-out", "serde_json", "serde" ]
diff --git a/bin/src/config.rs b/bin/src/config.rs
index 25c2a7f..d3944ac 100644
--- a/bin/src/config.rs
+++ b/bin/src/config.rs
@@ -2,17 +2,17 @@ use std::{default::Default, fmt, fs, path::PathBuf, str::FromStr};
 
 use crate::{dirs, err::ConfigErr};
 
-use clap::Clap;
+use clap::Parser;
 use vfs::ReadOnlyVfs;
 
-#[derive(Clap, Debug)]
+#[derive(Parser, Debug)]
 #[clap(version, author, about)]
 pub struct Opts {
     #[clap(subcommand)]
     pub cmd: SubCommand,
 }
 
-#[derive(Clap, Debug)]
+#[derive(Parser, Debug)]
 pub enum SubCommand {
     /// Lints and suggestions for the nix programming language
     Check(Check),
@@ -24,7 +24,7 @@ pub enum SubCommand {
     Explain(Explain),
 }
 
-#[derive(Clap, Debug)]
+#[derive(Parser, Debug)]
 pub struct Check {
     /// File or directory to run check on
     #[clap(default_value = ".", parse(from_os_str))]
@@ -67,7 +67,7 @@ impl Check {
     }
 }
 
-#[derive(Clap, Debug)]
+#[derive(Parser, Debug)]
 pub struct Fix {
     /// File or directory to run fix on
     #[clap(default_value = ".", parse(from_os_str))]
@@ -127,7 +127,7 @@ impl Fix {
     }
 }
 
-#[derive(Clap, Debug)]
+#[derive(Parser, Debug)]
 pub struct Single {
     /// File to run single-fix on
     #[clap(parse(from_os_str))]
@@ -174,7 +174,7 @@ impl Single {
     }
 }
 
-#[derive(Clap, Debug)]
+#[derive(Parser, Debug)]
 pub struct Explain {
     /// Warning code to explain
     #[clap(parse(try_from_str = parse_warning_code))]
diff --git a/bin/src/lib.rs b/bin/src/lib.rs
new file mode 100644
index 0000000..49c1a41
--- /dev/null
+++ b/bin/src/lib.rs
@@ -0,0 +1,7 @@
+pub mod config;
+pub mod dirs;
+pub mod err;
+pub mod explain;
+pub mod fix;
+pub mod lint;
+pub mod traits;
diff --git a/bin/src/main.rs b/bin/src/main.rs
index fabc509..f504796 100644
--- a/bin/src/main.rs
+++ b/bin/src/main.rs
@@ -1,15 +1,9 @@
-mod config;
-mod dirs;
-mod err;
-mod explain;
-mod fix;
-mod lint;
-mod traits;
-
-use crate::err::StatixErr;
-
-use clap::Clap;
-use config::{Opts, SubCommand};
+use clap::Parser;
+use statix::{
+    config::{Opts, SubCommand},
+    err::StatixErr,
+    explain, fix, lint,
+};
 
 fn _main() -> Result<(), StatixErr> {
     let opts = Opts::parse();
diff --git a/bin/tests/data/bool_comparison.nix b/bin/tests/data/bool_comparison.nix
new file mode 100644
index 0000000..dee2d08
--- /dev/null
+++ b/bin/tests/data/bool_comparison.nix
@@ -0,0 +1,13 @@
+[
+  # trivial
+  (a == true)
+  (b == true)
+  (true == c)
+  (true == d)
+
+  # not equals
+  (e != true)
+  (f != false)
+  (true != g)
+  (false != h)
+]
diff --git a/bin/tests/data/collapsible_let_in.nix b/bin/tests/data/collapsible_let_in.nix
new file mode 100644
index 0000000..7b41014
--- /dev/null
+++ b/bin/tests/data/collapsible_let_in.nix
@@ -0,0 +1,9 @@
+let
+  a = 2;
+  b = 3;
+in
+  let
+    c = 5;
+    d = 6;
+  in
+  a + b + c + d
diff --git a/bin/tests/data/deprecated_is_null.nix b/bin/tests/data/deprecated_is_null.nix
new file mode 100644
index 0000000..42596d7
--- /dev/null
+++ b/bin/tests/data/deprecated_is_null.nix
@@ -0,0 +1,6 @@
+let
+  e = null;
+in
+if isNull e
+then "no"
+else "yes"
diff --git a/bin/tests/data/empty_let_in.nix b/bin/tests/data/empty_let_in.nix
new file mode 100644
index 0000000..3ecb6e4
--- /dev/null
+++ b/bin/tests/data/empty_let_in.nix
@@ -0,0 +1,3 @@
+let
+in
+  null
diff --git a/bin/tests/data/empty_pattern.nix b/bin/tests/data/empty_pattern.nix
new file mode 100644
index 0000000..23d99e8
--- /dev/null
+++ b/bin/tests/data/empty_pattern.nix
@@ -0,0 +1,9 @@
+[
+  # match
+  ({ ... }: 42)
+
+  # don't match
+  ({ a, ... }: a)
+  ({ ... } @ inputs: inputs)
+]
+
diff --git a/bin/tests/data/eta_reduction.nix b/bin/tests/data/eta_reduction.nix
new file mode 100644
index 0000000..e717ee7
--- /dev/null
+++ b/bin/tests/data/eta_reduction.nix
@@ -0,0 +1,18 @@
+let
+  double = x: x * 2;
+  inherit (builtins) map;
+  xs = [ 1 2 3 ];
+  f = {
+    inherit double;
+    val = 2;
+  };
+in
+[
+  (map (x: double x) xs)
+
+  # don't lint on non-free exprs
+  (map (f: f.double f.val) [ f ])
+
+  # other non-free forms
+  (map (f: {inherit f;}.double f.val) [ f ])
+]
diff --git a/bin/tests/data/legacy_let_syntax.nix b/bin/tests/data/legacy_let_syntax.nix
new file mode 100644
index 0000000..46e3191
--- /dev/null
+++ b/bin/tests/data/legacy_let_syntax.nix
@@ -0,0 +1,5 @@
+let {
+  body = x + y;
+  x = "hello,";
+  y = " world!";
+}
diff --git a/bin/tests/data/manual_inherit.nix b/bin/tests/data/manual_inherit.nix
new file mode 100644
index 0000000..53ae4d7
--- /dev/null
+++ b/bin/tests/data/manual_inherit.nix
@@ -0,0 +1,12 @@
+let
+  a = 2;
+  y = "y";
+in
+{
+  # trivial
+  a = a;
+
+  # don't lint
+  x.y = y;
+}
+
diff --git a/bin/tests/data/manual_inherit_from.nix b/bin/tests/data/manual_inherit_from.nix
new file mode 100644
index 0000000..214b2a3
--- /dev/null
+++ b/bin/tests/data/manual_inherit_from.nix
@@ -0,0 +1,8 @@
+let
+  a = {b = 2; c = 3;};
+in
+{
+  b = a.b;
+  c = a.c;
+}
+
diff --git a/bin/tests/data/redundant_pattern_bind.nix b/bin/tests/data/redundant_pattern_bind.nix
new file mode 100644
index 0000000..d328c50
--- /dev/null
+++ b/bin/tests/data/redundant_pattern_bind.nix
@@ -0,0 +1 @@
+{ ... }  @ inputs: null
diff --git a/bin/tests/data/unquoted_splices.nix b/bin/tests/data/unquoted_splices.nix
new file mode 100644
index 0000000..30935b0
--- /dev/null
+++ b/bin/tests/data/unquoted_splices.nix
@@ -0,0 +1,15 @@
+let
+  x = 2;
+  y = 3;
+  a = { "2" = y; };
+in
+[
+  ${x}
+  ${toString (x + y)}
+  a.${toString x}
+
+  # multiline test
+  ${
+    toString x
+  }
+]
diff --git a/bin/tests/data/unquoted_uri.nix b/bin/tests/data/unquoted_uri.nix
new file mode 100644
index 0000000..e56574a
--- /dev/null
+++ b/bin/tests/data/unquoted_uri.nix
@@ -0,0 +1 @@
+github:nerdypepper/statix
diff --git a/bin/tests/data/useless_parens.nix b/bin/tests/data/useless_parens.nix
new file mode 100644
index 0000000..cf26441
--- /dev/null
+++ b/bin/tests/data/useless_parens.nix
@@ -0,0 +1,16 @@
+let
+  # parens around primitives
+  a = {
+    b = ("hello");
+    c = (d);
+    e = ({ f = 2; });
+  };
+
+  # parens around let-value
+  g = (1 + 2);
+  h = ({ inherit i; });
+
+  # TODO: binary exprs, function args etc.
+in
+  # parens around let body
+  (null)
diff --git a/bin/tests/main.rs b/bin/tests/main.rs
new file mode 100644
index 0000000..6175c90
--- /dev/null
+++ b/bin/tests/main.rs
@@ -0,0 +1,47 @@
+mod util {
+    #[macro_export]
+    macro_rules! test_lint {
+        ($($tname:ident),*,) => {
+            test_lint!($($tname),*);
+        };
+        ($($tname:ident),*) => {
+            $(
+                #[test]
+                fn $tname() {
+                    use statix::{config::OutFormat, traits::WriteDiagnostic, lint};
+                    use vfs::ReadOnlyVfs;
+
+                    let file_path = concat!("data/", stringify!($tname), ".nix");
+                    let contents = include_str!(concat!("data/", stringify!($tname), ".nix"));
+
+                    let vfs = ReadOnlyVfs::singleton(file_path, contents.as_bytes());
+
+                    let mut buffer = Vec::new();
+                    vfs.iter().map(lint::lint).for_each(|r| {
+                        buffer.write(&r, &vfs, OutFormat::StdErr).unwrap();
+                    });
+
+                    let stripped = strip_ansi_escapes::strip(&buffer).unwrap();
+                    let out =  std::str::from_utf8(&stripped).unwrap();
+                    insta::assert_snapshot!(&out);
+                }
+            )*
+        };
+    }
+}
+
+test_lint! {
+    bool_comparison,
+    empty_let_in,
+    manual_inherit,
+    manual_inherit_from,
+    legacy_let_syntax,
+    collapsible_let_in,
+    eta_reduction,
+    useless_parens,
+    unquoted_splices,
+    empty_pattern,
+    redundant_pattern_bind,
+    unquoted_uri,
+    deprecated_is_null,
+}
diff --git a/bin/tests/snapshots/main__bool_comparison.snap b/bin/tests/snapshots/main__bool_comparison.snap
new file mode 100644
index 0000000..0865332
--- /dev/null
+++ b/bin/tests/snapshots/main__bool_comparison.snap
@@ -0,0 +1,62 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W01] Warning: Unnecessary comparison with boolean
+   ╭─[data/bool_comparison.nix:3:4]
+   │
+ 3 │   (a == true)
+   ·    ────┬────  
+   ·        ╰────── Comparing a with boolean literal true
+───╯
+[W01] Warning: Unnecessary comparison with boolean
+   ╭─[data/bool_comparison.nix:4:4]
+   │
+ 4 │   (b == true)
+   ·    ────┬────  
+   ·        ╰────── Comparing b with boolean literal true
+───╯
+[W01] Warning: Unnecessary comparison with boolean
+   ╭─[data/bool_comparison.nix:5:4]
+   │
+ 5 │   (true == c)
+   ·    ────┬────  
+   ·        ╰────── Comparing c with boolean literal true
+───╯
+[W01] Warning: Unnecessary comparison with boolean
+   ╭─[data/bool_comparison.nix:6:4]
+   │
+ 6 │   (true == d)
+   ·    ────┬────  
+   ·        ╰────── Comparing d with boolean literal true
+───╯
+[W01] Warning: Unnecessary comparison with boolean
+   ╭─[data/bool_comparison.nix:9:4]
+   │
+ 9 │   (e != true)
+   ·    ────┬────  
+   ·        ╰────── Comparing e with boolean literal true
+───╯
+[W01] Warning: Unnecessary comparison with boolean
+    ╭─[data/bool_comparison.nix:10:4]
+    │
+ 10 │   (f != false)
+    ·    ─────┬────  
+    ·         ╰────── Comparing f with boolean literal false
+────╯
+[W01] Warning: Unnecessary comparison with boolean
+    ╭─[data/bool_comparison.nix:11:4]
+    │
+ 11 │   (true != g)
+    ·    ────┬────  
+    ·        ╰────── Comparing g with boolean literal true
+────╯
+[W01] Warning: Unnecessary comparison with boolean
+    ╭─[data/bool_comparison.nix:12:4]
+    │
+ 12 │   (false != h)
+    ·    ─────┬────  
+    ·         ╰────── Comparing h with boolean literal false
+────╯
+
diff --git a/bin/tests/snapshots/main__collapsible_let_in.snap b/bin/tests/snapshots/main__collapsible_let_in.snap
new file mode 100644
index 0000000..b135abc
--- /dev/null
+++ b/bin/tests/snapshots/main__collapsible_let_in.snap
@@ -0,0 +1,17 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W06] Warning: These let-in expressions are collapsible
+   ╭─[data/collapsible_let_in.nix:1:1]
+   │
+ 1 │ ╭───▶ let
+ 5 │ │ ╭─▶   let
+ 9 │ │ ├─▶   a + b + c + d
+   · │ │                 │   
+   · │ ╰───────────────────── This let in expression is nested
+   · │                   │   
+   · ╰───────────────────┴─── This let in expression contains a nested let in expression
+───╯
+
diff --git a/bin/tests/snapshots/main__deprecated_is_null.snap b/bin/tests/snapshots/main__deprecated_is_null.snap
new file mode 100644
index 0000000..d49b381
--- /dev/null
+++ b/bin/tests/snapshots/main__deprecated_is_null.snap
@@ -0,0 +1,13 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W13] Warning: Found usage of deprecated builtin isNull
+   ╭─[data/deprecated_is_null.nix:4:4]
+   │
+ 4 │ if isNull e
+   ·    ────┬───  
+   ·        ╰───── isNull is deprecated, check equality with null instead
+───╯
+
diff --git a/bin/tests/snapshots/main__empty_let_in.snap b/bin/tests/snapshots/main__empty_let_in.snap
new file mode 100644
index 0000000..426692f
--- /dev/null
+++ b/bin/tests/snapshots/main__empty_let_in.snap
@@ -0,0 +1,14 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W02] Warning: Useless let-in expression
+   ╭─[data/empty_let_in.nix:1:1]
+   │
+ 1 │ ╭─▶ let
+ 3 │ ├─▶   null
+   · │            
+   · ╰──────────── This let-in expression has no entries
+───╯
+
diff --git a/bin/tests/snapshots/main__empty_pattern.snap b/bin/tests/snapshots/main__empty_pattern.snap
new file mode 100644
index 0000000..3ea7ae0
--- /dev/null
+++ b/bin/tests/snapshots/main__empty_pattern.snap
@@ -0,0 +1,20 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W10] Warning: Found empty pattern in function argument
+   ╭─[data/empty_pattern.nix:3:4]
+   │
+ 3 │   ({ ... }: 42)
+   ·    ───┬───  
+   ·       ╰───── This pattern is empty, use _ instead
+───╯
+[W11] Warning: Found redundant pattern bind in function argument
+   ╭─[data/empty_pattern.nix:7:4]
+   │
+ 7 │   ({ ... } @ inputs: inputs)
+   ·    ────────┬───────  
+   ·            ╰───────── This pattern bind is redundant, use inputs instead
+───╯
+
diff --git a/bin/tests/snapshots/main__eta_reduction.snap b/bin/tests/snapshots/main__eta_reduction.snap
new file mode 100644
index 0000000..6271980
--- /dev/null
+++ b/bin/tests/snapshots/main__eta_reduction.snap
@@ -0,0 +1,13 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W07] Warning: This function expression is eta reducible
+    ╭─[data/eta_reduction.nix:11:9]
+    │
+ 11 │   (map (x: double x) xs)
+    ·         ─────┬─────  
+    ·              ╰─────── Found eta-reduction: double
+────╯
+
diff --git a/bin/tests/snapshots/main__legacy_let_syntax.snap b/bin/tests/snapshots/main__legacy_let_syntax.snap
new file mode 100644
index 0000000..35aa7ee
--- /dev/null
+++ b/bin/tests/snapshots/main__legacy_let_syntax.snap
@@ -0,0 +1,14 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W05] Warning: Using undocumented `let` syntax
+   ╭─[data/legacy_let_syntax.nix:1:1]
+   │
+ 1 │ ╭─▶ let {
+ 5 │ ├─▶ }
+   · │       
+   · ╰─────── Prefer rec over undocumented let syntax
+───╯
+
diff --git a/bin/tests/snapshots/main__manual_inherit.snap b/bin/tests/snapshots/main__manual_inherit.snap
new file mode 100644
index 0000000..063867c
--- /dev/null
+++ b/bin/tests/snapshots/main__manual_inherit.snap
@@ -0,0 +1,13 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W03] Warning: Assignment instead of inherit
+   ╭─[data/manual_inherit.nix:7:3]
+   │
+ 7 │   a = a;
+   ·   ───┬──  
+   ·      ╰──── This assignment is better written with inherit
+───╯
+
diff --git a/bin/tests/snapshots/main__manual_inherit_from.snap b/bin/tests/snapshots/main__manual_inherit_from.snap
new file mode 100644
index 0000000..9cf1f5d
--- /dev/null
+++ b/bin/tests/snapshots/main__manual_inherit_from.snap
@@ -0,0 +1,20 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W04] Warning: Assignment instead of inherit from
+   ╭─[data/manual_inherit_from.nix:5:3]
+   │
+ 5 │   b = a.b;
+   ·   ────┬───  
+   ·       ╰───── This assignment is better written with inherit
+───╯
+[W04] Warning: Assignment instead of inherit from
+   ╭─[data/manual_inherit_from.nix:6:3]
+   │
+ 6 │   c = a.c;
+   ·   ────┬───  
+   ·       ╰───── This assignment is better written with inherit
+───╯
+
diff --git a/bin/tests/snapshots/main__redundant_pattern_bind.snap b/bin/tests/snapshots/main__redundant_pattern_bind.snap
new file mode 100644
index 0000000..2f26818
--- /dev/null
+++ b/bin/tests/snapshots/main__redundant_pattern_bind.snap
@@ -0,0 +1,13 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W11] Warning: Found redundant pattern bind in function argument
+   ╭─[data/redundant_pattern_bind.nix:1:1]
+   │
+ 1 │ { ... }  @ inputs: null
+   · ────────┬────────  
+   ·         ╰────────── This pattern bind is redundant, use inputs instead
+───╯
+
diff --git a/bin/tests/snapshots/main__unquoted_splices.snap b/bin/tests/snapshots/main__unquoted_splices.snap
new file mode 100644
index 0000000..5fd1917
--- /dev/null
+++ b/bin/tests/snapshots/main__unquoted_splices.snap
@@ -0,0 +1,35 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W09] Warning: Found unquoted splice expression
+   ╭─[data/unquoted_splices.nix:7:3]
+   │
+ 7 │   ${x}
+   ·   ──┬─  
+   ·     ╰─── Consider quoting this splice expression
+───╯
+[W09] Warning: Found unquoted splice expression
+   ╭─[data/unquoted_splices.nix:8:3]
+   │
+ 8 │   ${toString (x + y)}
+   ·   ─────────┬─────────  
+   ·            ╰─────────── Consider quoting this splice expression
+───╯
+[W09] Warning: Found unquoted splice expression
+   ╭─[data/unquoted_splices.nix:9:5]
+   │
+ 9 │   a.${toString x}
+   ·     ──────┬──────  
+   ·           ╰──────── Consider quoting this splice expression
+───╯
+[W09] Warning: Found unquoted splice expression
+    ╭─[data/unquoted_splices.nix:12:3]
+    │
+ 12 │ ╭─▶   ${
+ 14 │ ├─▶   }
+    · │         
+    · ╰───────── Consider quoting this splice expression
+────╯
+
diff --git a/bin/tests/snapshots/main__unquoted_uri.snap b/bin/tests/snapshots/main__unquoted_uri.snap
new file mode 100644
index 0000000..2f0e5a9
--- /dev/null
+++ b/bin/tests/snapshots/main__unquoted_uri.snap
@@ -0,0 +1,13 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W12] Warning: Found unquoted URI expression
+   ╭─[data/unquoted_uri.nix:1:1]
+   │
+ 1 │ github:nerdypepper/statix
+   · ────────────┬────────────  
+   ·             ╰────────────── Consider quoting this URI expression
+───╯
+
diff --git a/bin/tests/snapshots/main__useless_parens.snap b/bin/tests/snapshots/main__useless_parens.snap
new file mode 100644
index 0000000..d44176e
--- /dev/null
+++ b/bin/tests/snapshots/main__useless_parens.snap
@@ -0,0 +1,48 @@
+---
+source: bin/tests/main.rs
+expression: "&out"
+
+---
+[W08] Warning: These parentheses can be omitted
+    ╭─[data/useless_parens.nix:16:3]
+    │
+ 16 │   (null)
+    ·   ───┬──  
+    ·      ╰──── Useless parentheses around body of let expression
+────╯
+[W08] Warning: These parentheses can be omitted
+   ╭─[data/useless_parens.nix:4:9]
+   │
+ 4 │     b = ("hello");
+   ·         ────┬────  
+   ·             ╰────── Useless parentheses around value in binding
+───╯
+[W08] Warning: These parentheses can be omitted
+   ╭─[data/useless_parens.nix:5:9]
+   │
+ 5 │     c = (d);
+   ·         ─┬─  
+   ·          ╰─── Useless parentheses around value in binding
+───╯
+[W08] Warning: These parentheses can be omitted
+   ╭─[data/useless_parens.nix:6:9]
+   │
+ 6 │     e = ({ f = 2; });
+   ·         ──────┬─────  
+   ·               ╰─────── Useless parentheses around value in binding
+───╯
+[W08] Warning: These parentheses can be omitted
+    ╭─[data/useless_parens.nix:10:7]
+    │
+ 10 │   g = (1 + 2);
+    ·       ───┬───  
+    ·          ╰───── Useless parentheses around value in binding
+────╯
+[W08] Warning: These parentheses can be omitted
+    ╭─[data/useless_parens.nix:11:7]
+    │
+ 11 │   h = ({ inherit i; });
+    ·       ────────┬───────  
+    ·               ╰───────── Useless parentheses around value in binding
+────╯
+