Add gix-config-value fuzzer

- Add fuzzer
- Add associated dict

Author: nathaniel-brough

gix-config-value/fuzz/.gitignore

@@ -0,0 +1,4 @@
+target
+corpus
+artifacts
+coverage

gix-config-value/fuzz/Cargo.toml

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+[package]
+name = "gix-config-value-fuzz"
+version = "0.0.0"
+publish = false
+edition = "2021"
+
+[package.metadata]
+cargo-fuzz = true
+
+[dependencies]
+libfuzzer-sys = "0.4"
+gix-config-value = { path = ".." }
+anyhow = "1.0.78"
+bstr = "1.9.0"
+arbitrary = { version = "1.3.2", features = ["derive"] }
+
+# Prevent this from interfering with workspaces
+[workspace]
+members = ["."]
+
+[profile.release]
+debug = 1
+
+[[bin]]
+name = "fuzz_value"
+path = "fuzz_targets/fuzz_value.rs"
+test = false
+doc = false

gix-config-value/fuzz/fuzz_targets/fuzz_value.dict

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+# Names
+"normal"
+"default"
+"black"
+"brightblack"
+"red"
+"brightred"
+"green"
+"brightgreen"
+"yellow"
+"brightyellow"
+"blue"
+"brightblue"
+"magenta"
+"brightmagenta"
+"cyan"
+"brightcyan"
+"white"
+"brightwhite"
+
+# Attributes
+"reset"
+"bold"
+"nobold"
+"dim"
+"nodim"
+"ul"
+"noul"
+"blink"
+"noblink"
+"reverse"
+"noreverse"
+"italic"
+"noitalic"
+"strike"
+"nostrike"

gix-config-value/fuzz/fuzz_targets/fuzz_value.rs

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+#![no_main]
+
+extern crate libfuzzer_sys;
+
+use anyhow::Result;
+use arbitrary::Arbitrary;
+use bstr::{BStr, BString};
+use gix_config_value::{
+    color::{Attribute, Name},
+    path::interpolate::Context,
+    Boolean, Color, Integer, Path,
+};
+use libfuzzer_sys::fuzz_target;
+use std::{borrow::Cow, hint::black_box, str::FromStr};
+
+#[derive(Debug, Arbitrary)]
+struct Ctx<'a> {
+    bool_str: &'a [u8],
+    color_str: &'a [u8],
+    integer_str: &'a [u8],
+    path_str: &'a [u8],
+    attribute_str: &'a str,
+    name_str: &'a str,
+}
+
+fn fuzz(ctx: Ctx) -> Result<()> {
+    let b = Boolean::try_from(BStr::new(ctx.bool_str))?;
+    _ = black_box(b.is_true());
+
+    _ = black_box(Color::try_from(BStr::new(ctx.color_str)))?;
+
+    let a = Attribute::from_str(ctx.attribute_str)?;
+    _ = black_box(format!("{a}"));
+
+    let name = Name::from_str(ctx.name_str)?;
+    _ = black_box(format!("{name}"));
+
+    let i = Integer::try_from(BStr::new(ctx.integer_str))?;
+    _ = black_box(i.to_decimal());
+
+    let p = Path::try_from(Cow::Owned(BString::from(ctx.path_str)))?;
+    _ = black_box(p.interpolate(Context::default()));
+
+    Ok(())
+}
+
+fuzz_target!(|ctx: Ctx| {
+    if let Err(e) = fuzz(ctx) {
+        // Excersize display/debug fmt code.
+        _ = black_box(format!("{e} {e:?}"));
+    }
+});