rework cli, fix is now a flag, implement dry-run mode

5 files changed, 120 insertions, 102 deletions

diff --git a/bin/src/config.rs b/bin/src/config.rs
index cb03a4b..6d7bc49 100644
--- a/bin/src/config.rs
+++ b/bin/src/config.rs
@@ -17,39 +17,30 @@ use crate::err::ConfigErr;
 pub struct Opts {
     /// File or directory to run statix on
     #[clap(default_value = ".")]
-    target: String,
+    pub target: String,
 
-    // /// Path to statix config
-    // #[clap(short, long, default_value = ".statix.toml")]
-    // config: String,
-    /// Regex of file patterns to not lint
+    /// Globs of file patterns to skip
     #[clap(short, long)]
-    ignore: Vec<String>,
+    pub ignore: Vec<String>,
 
-    /// Output format. Supported values: json, errfmt
+    /// Output format.
+    /// Supported values: errfmt, json (on feature flag only)
     #[clap(short = 'o', long)]
     format: Option<OutFormat>,
 
-    #[clap(subcommand)]
-    pub subcmd: Option<SubCommand>,
-}
-
-#[derive(Clap, Debug)]
-#[clap(version = "0.1.0", author = "Akshay <[email protected]>")]
-pub enum SubCommand {
     /// Find and fix issues raised by statix
-    Fix(Fix),
-}
+    #[clap(short = 'f', long)]
+    pub fix: bool,
 
-#[derive(Clap, Debug)]
-pub struct Fix {
-    /// Do not write to files, display a diff instead
+    /// Do not fix files in place, display a diff instead
     #[clap(short = 'd', long = "dry-run")]
     diff_only: bool,
 }
 
+
 #[derive(Debug, Copy, Clone)]
 pub enum OutFormat {
+    #[cfg(feature = "json")]
     Json,
     Errfmt,
     StdErr,
@@ -66,9 +57,10 @@ impl FromStr for OutFormat {
 
     fn from_str(value: &str) -> Result<Self, Self::Err> {
         match value.to_ascii_lowercase().as_str() {
-            "json" => Ok(Self::Json),
+            #[cfg(feature = "json")] "json" => Ok(Self::Json),
             "errfmt" => Ok(Self::Errfmt),
             "stderr" => Ok(Self::StdErr),
+            "json" => Err("statix was not compiled with the `json` feature flag"),
             _ => Err("unknown output format, try: json, errfmt"),
         }
     }
@@ -122,11 +114,7 @@ impl FixConfig {
             .filter(|path| !ignores.is_match(path))
             .collect();
 
-        let diff_only = match opts.subcmd {
-            Some(SubCommand::Fix(f)) => f.diff_only,
-            _ => false,
-        };
-
+        let diff_only = opts.diff_only;
         Ok(Self { files, diff_only })
     }
 
diff --git a/bin/src/err.rs b/bin/src/err.rs
index c9db4d5..727e0cc 100644
--- a/bin/src/err.rs
+++ b/bin/src/err.rs
@@ -23,6 +23,8 @@ pub enum LintErr {
 pub enum FixErr {
     #[error("[{0}] syntax error: {1}")]
     Parse(PathBuf, ParseError),
+    #[error("path error: {0}")]
+    InvalidPath(#[from] io::Error),
 }
 
 #[derive(Error, Debug)]
diff --git a/bin/src/fix.rs b/bin/src/fix.rs
index 478dbd9..d9087fe 100644
--- a/bin/src/fix.rs
+++ b/bin/src/fix.rs
@@ -65,48 +65,40 @@ pub struct Fixed {
 
 impl<'a> FixResult<'a> {
     fn empty(src: Source<'a>) -> Self {
-        Self { src, fixed: vec![] }
+        Self { src, fixed: Vec::new() }
     }
 }
 
-fn next(mut src: Source) -> Result<FixResult, RnixParseErr> {
-    let all_reports = collect_fixes(&src)?;
-
-    if all_reports.is_empty() {
-        return Ok(FixResult::empty(src));
-    }
+impl<'a> Iterator for FixResult<'a> {
+    type Item = FixResult<'a>;
+    fn next(&mut self) -> Option<Self::Item> {
+        let all_reports = collect_fixes(&self.src).ok()?;
+        if all_reports.is_empty() {
+            return None;
+        }
 
-    let reordered = reorder(all_reports);
+        let reordered = reorder(all_reports);
+        let fixed = reordered
+            .iter()
+            .map(|r| Fixed {
+                at: r.range(),
+                code: r.code,
+            })
+            .collect::<Vec<_>>();
+        for report in reordered {
+            report.apply(self.src.to_mut());
+        }
 
-    let fixed = reordered
-        .iter()
-        .map(|r| Fixed {
-            at: r.range(),
-            code: r.code,
+        Some(FixResult {
+            src: self.src.clone(),
+            fixed
         })
-        .collect::<Vec<_>>();
-    for report in reordered {
-        report.apply(src.to_mut());
     }
-
-    Ok(FixResult {
-        src,
-        fixed
-    })
 }
 
-pub fn fix(src: &str) -> Result<FixResult, RnixParseErr> {
+pub fn fix(src: &str) -> Option<FixResult> {
     let src = Cow::from(src);
-    let _ = rnix::parse(&src).as_result()?;
-    let mut initial = FixResult::empty(src);
-
-    while let Ok(next_result) = next(initial.src)  {
-        if next_result.fixed.is_empty() {
-            return Ok(next_result);
-        } else {
-            initial = FixResult::empty(next_result.src);
-        }
-    }
-
-    unreachable!("a fix caused a syntax error, please report a bug");
+    let _ = rnix::parse(&src).as_result().ok()?;
+    let initial = FixResult::empty(src);
+    initial.into_iter().last()
 }
diff --git a/bin/src/main.rs b/bin/src/main.rs
index 6f0343e..d0f69a0 100644
--- a/bin/src/main.rs
+++ b/bin/src/main.rs
@@ -6,55 +6,50 @@ mod traits;
 
 use std::io;
 
-use crate::{
-    err::{FixErr, StatixErr},
-    traits::WriteDiagnostic,
-};
+use crate::{err::{StatixErr, FixErr}, traits::WriteDiagnostic};
 
 use clap::Clap;
-use config::{FixConfig, LintConfig, Opts, SubCommand};
+use config::{FixConfig, LintConfig, Opts};
 use similar::TextDiff;
 
 fn _main() -> Result<(), StatixErr> {
     let opts = Opts::parse();
-    match opts.subcmd {
-        Some(SubCommand::Fix(_)) => {
-            let fix_config = FixConfig::from_opts(opts)?;
-            let vfs = fix_config.vfs()?;
-            for entry in vfs.iter() {
-                match fix::fix(entry.contents) {
-                    Ok(fix_result) => {
-                        let text_diff = TextDiff::from_lines(entry.contents, &fix_result.src);
-                        let old_file = format!("{}", entry.file_path.display());
-                        let new_file = format!("{} [fixed]", entry.file_path.display());
-                        println!(
-                            "{}",
-                            text_diff
-                                .unified_diff()
-                                .context_radius(4)
-                                .header(&old_file, &new_file)
-                        );
-                    }
-                    Err(e) => eprintln!("{}", FixErr::Parse(entry.file_path.to_path_buf(), e)),
+    if opts.fix {
+        let fix_config = FixConfig::from_opts(opts)?;
+        let vfs = fix_config.vfs()?;
+        for entry in vfs.iter() {
+            if let Some(fix_result) = fix::fix(entry.contents) {
+                if fix_config.diff_only {
+                    let text_diff = TextDiff::from_lines(entry.contents, &fix_result.src);
+                    let old_file = format!("{}", entry.file_path.display());
+                    let new_file = format!("{} [fixed]", entry.file_path.display());
+                    println!(
+                        "{}",
+                        text_diff
+                            .unified_diff()
+                            .context_radius(4)
+                            .header(&old_file, &new_file)
+                    );
+                } else {
+                    let path = entry.file_path;
+                    std::fs::write(path, &*fix_result.src).map_err(FixErr::InvalidPath)?;
                 }
             }
         }
-        None => {
-            let lint_config = LintConfig::from_opts(opts)?;
-            let vfs = lint_config.vfs()?;
-            let (lints, errors): (Vec<_>, Vec<_>) =
-                vfs.iter().map(lint::lint).partition(Result::is_ok);
-            let lint_results = lints.into_iter().map(Result::unwrap);
-            let errors = errors.into_iter().map(Result::unwrap_err);
+    } else {
+        let lint_config = LintConfig::from_opts(opts)?;
+        let vfs = lint_config.vfs()?;
+        let (lints, errors): (Vec<_>, Vec<_>) = vfs.iter().map(lint::lint).partition(Result::is_ok);
+        let lint_results = lints.into_iter().map(Result::unwrap);
+        let errors = errors.into_iter().map(Result::unwrap_err);
 
-            let mut stderr = io::stderr();
-            lint_results.for_each(|r| {
-                stderr.write(&r, &vfs, lint_config.format).unwrap();
-            });
-            errors.for_each(|e| {
-                eprintln!("{}", e);
-            });
-        }
+        let mut stdout = io::stdout();
+        lint_results.for_each(|r| {
+            stdout.write(&r, &vfs, lint_config.format).unwrap();
+        });
+        errors.for_each(|e| {
+            eprintln!("{}", e);
+        });
     }
     Ok(())
 }
diff --git a/readme.md b/readme.md
index 9ccb66e..68265cc 100644
--- a/readme.md
+++ b/readme.md
@@ -1,12 +1,53 @@
-## statix
+# statix
 
-`statix` intends to be a static analysis tool for the
-Nix programming language.
+> Lints and suggestions for the Nix programming language.
+
+`statix` highlights antipatterns in Nix code. `statix fix`
+can fix several such occurrences.
 
 For the time-being, `statix` works only with ASTs
 produced by the `rnix-parser` crate and does not evaluate
 any nix code (imports, attr sets etc.). 
 
+## Installation
+
+`statix` is available via a nix flake:
+
+```
+nix run git+https://git.peppe.rs/languages/statix
+
+# or
+
+nix build git+https://git.peppe.rs/languages/statix
+./result/bin/statix --help
+```
+
+## Usage
+
+```
+statix 0.1.0
+
+Akshay <[email protected]>
+
+Lints and suggestions for the Nix programming language
+
+USAGE:
+    statix [FLAGS] [OPTIONS] [--] [TARGET]
+
+ARGS:
+    <TARGET>    File or directory to run statix on [default: .]
+
+FLAGS:
+    -d, --dry-run    Do not fix files in place, display a diff instead
+    -f, --fix        Find and fix issues raised by statix
+    -h, --help       Print help information
+    -V, --version    Print version information
+
+OPTIONS:
+    -i, --ignore <IGNORE>...    Globs of file patterns to skip
+    -o, --format <FORMAT>       Output format. Supported values: errfmt, json (on feature flag only)
+```
+
 ## Architecture
 
 `statix` has the following components:
@@ -37,5 +78,5 @@ their metadata.
 ## TODO
 
 - Offline documentation for each lint
-- Automatically fix all lints from suggestions generated
 - Test suite for lints and suggestions
+- Output singleline/errfmt + vim plugin