Properly support nested globs when there are conflicts

src/glob.rs

@@ -1,5 +1,5 @@
 use std::env;
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::sync::Mutex;
 
 use globset::{GlobBuilder, GlobMatcher};
@@ -55,6 +55,8 @@ pub fn glob_exec<F: FnMut(&Path)>(base: &Path, pattern: &str, mut f: F) {
         fail_fast: std::env::var("INSTA_GLOB_FAIL_FAST").as_deref() == Ok("1"),
     });
 
+    // step 1: collect all matching files
+    let mut matching_files = vec![];
     for file in walker {
         let file = file.unwrap();
         let path = file.path();
@@ -71,9 +73,26 @@ pub fn glob_exec<F: FnMut(&Path)>(base: &Path, pattern: &str, mut f: F) {
             continue;
         }
 
+        matching_files.push(path.to_path_buf());
+    }
+
+    // step 2: sort, determine common prefix and run assertions
+    matching_files.sort();
+    let common_prefix = find_common_prefix(&matching_files);
+    for path in &matching_files {
         settings.set_input_file(path);
-        settings.set_snapshot_suffix(path.file_name().unwrap().to_str().unwrap());
 
+        // if there is a common prefix, use that stirp down the input file.  That way we
+        // can ensure that a glob like inputs/*/*.txt with a/file.txt and b/file.txt
+        // does not create two identical snapshot suffixes.  Instead of file.txt for both
+        // it would end up as a/file.txt and b/file.txt.
+        let snapshot_suffix = if let Some(prefix) = common_prefix {
+            path.strip_prefix(prefix).unwrap().as_os_str()
+        } else {
+            path.file_name().unwrap()
+        };
+
+        settings.set_snapshot_suffix(snapshot_suffix.to_str().unwrap());
         settings.bind(|| {
             f(path);
         });
@@ -104,3 +123,23 @@ pub fn glob_exec<F: FnMut(&Path)>(base: &Path, pattern: &str, mut f: F) {
         );
     }
 }
+
+fn find_common_prefix(sorted_paths: &[PathBuf]) -> Option<&Path> {
+    let first = sorted_paths.first()?;
+    let last = sorted_paths.last()?;
+    let prefix_len = first
+        .components()
+        .zip(last.components())
+        .take_while(|(a, b)| a == b)
+        .count();
+
+    if prefix_len == 0 {
+        None
+    } else {
+        let mut prefix = first.components();
+        for _ in 0..first.components().count() - prefix_len {
+            prefix.next_back();
+        }
+        Some(prefix.as_path())
+    }
+}

tests/inputs-nested/a/file.txt

@@ -0,0 +1 @@
+Hello A

tests/inputs-nested/b/file.txt

@@ -0,0 +1 @@
+Hello B

tests/snapshots/test_glob__basic_globbing_nested@a__file.txt.snap

@@ -0,0 +1,7 @@
+---
+source: tests/test_glob.rs
+expression: "&contents"
+input_file: tests/inputs-nested/a/file.txt
+---
+Hello A
+

tests/snapshots/test_glob__basic_globbing_nested@b__file.txt.snap

@@ -0,0 +1,7 @@
+---
+source: tests/test_glob.rs
+expression: "&contents"
+input_file: tests/inputs-nested/b/file.txt
+---
+Hello B
+

tests/test_glob.rs

@@ -8,6 +8,14 @@ fn test_basic_globbing() {
     });
 }
 
+#[test]
+fn test_basic_globbing_nested() {
+    insta::glob!("inputs-nested/*/*.txt", |path| {
+        let contents = std::fs::read_to_string(path).unwrap();
+        insta::assert_snapshot!(&contents);
+    });
+}
+
 #[test]
 fn test_globs_follow_links() {
     insta::glob!("link-to-inputs/*.txt", |path| {