diff --git a/crates/agent/src/tools/grep_tool.rs b/crates/agent/src/tools/grep_tool.rs
index 0caba91564fd1f..6becd54e8623a1 100644
--- a/crates/agent/src/tools/grep_tool.rs
+++ b/crates/agent/src/tools/grep_tool.rs
@@ -170,12 +170,15 @@ impl AgentTool for GrepTool {
             Err(error) => return Task::ready(Err(error)),
         };
 
-        let results = self
+        let (results, search_task) = self
             .project
             .update(cx, |project, cx| project.search(query, cx));
 
         let project = self.project.downgrade();
         cx.spawn(async move |cx|  {
+            // Keep the search alive for the duration of result iteration. Dropping this task is the
+            // cancellation mechanism; we intentionally do not detach it.
+            let _search_task = search_task;
             futures::pin_mut!(results);
 
             let mut output = String::new();
diff --git a/crates/collab/src/tests/integration_tests.rs b/crates/collab/src/tests/integration_tests.rs
index 391e7355ea196d..e205abb32f37e4 100644
--- a/crates/collab/src/tests/integration_tests.rs
+++ b/crates/collab/src/tests/integration_tests.rs
@@ -5179,7 +5179,7 @@ async fn test_project_search(
 
     // Perform a search as the guest.
     let mut results = HashMap::default();
-    let search_rx = project_b.update(cx_b, |project, cx| {
+    let (search_rx, search_task) = project_b.update(cx_b, |project, cx| {
         project.search(
             SearchQuery::text(
                 "world",
@@ -5195,6 +5195,8 @@ async fn test_project_search(
             cx,
         )
     });
+    // Keep the search task alive while we drain the receiver; dropping it cancels the search.
+    let _search_task = search_task;
     while let Ok(result) = search_rx.recv().await {
         match result {
             SearchResult::Buffer { buffer, ranges } => {
diff --git a/crates/collab/src/tests/random_project_collaboration_tests.rs b/crates/collab/src/tests/random_project_collaboration_tests.rs
index 7e9b84c0571ed6..27b97b4a87734e 100644
--- a/crates/collab/src/tests/random_project_collaboration_tests.rs
+++ b/crates/collab/src/tests/random_project_collaboration_tests.rs
@@ -886,7 +886,7 @@ impl RandomizedTest for ProjectCollaborationTest {
                     if detach { "detaching" } else { "awaiting" }
                 );
 
-                let search = project.update(cx, |project, cx| {
+                let (search, search_task) = project.update(cx, |project, cx| {
                     project.search(
                         SearchQuery::text(
                             query,
@@ -904,6 +904,9 @@ impl RandomizedTest for ProjectCollaborationTest {
                 });
                 drop(project);
                 let search = cx.executor().spawn(async move {
+                    // Keep the search task alive while we drain the receiver; dropping it cancels the search.
+                    let _search_task = search_task;
+
                     let mut results = HashMap::default();
                     while let Ok(result) = search.recv().await {
                         if let SearchResult::Buffer { buffer, ranges } = result {
diff --git a/crates/dap_adapters/src/go.rs b/crates/dap_adapters/src/go.rs
index d3253d5fe250f7..3c6752ed3ebfe9 100644
--- a/crates/dap_adapters/src/go.rs
+++ b/crates/dap_adapters/src/go.rs
@@ -8,6 +8,7 @@ use dap::{
     },
 };
 use fs::Fs;
+use futures::AsyncReadExt as _;
 use gpui::{AsyncApp, SharedString};
 use language::LanguageName;
 use log::warn;
@@ -557,10 +558,18 @@ async fn handle_envs(
             continue;
         };
 
-        if let Ok(file) = fs.open_sync(&path).await {
-            let file_envs: HashMap<String, String> = dotenvy::from_read_iter(file)
-                .filter_map(Result::ok)
-                .collect();
+        if let Ok(mut file) = fs.open_read(&path).await {
+            let mut bytes = Vec::new();
+            if file.read_to_end(&mut bytes).await.is_err() {
+                warn!("While starting Go debug session: failed to read env file {path:?}");
+                continue;
+            }
+
+            let file_envs: HashMap<String, String> =
+                dotenvy::from_read_iter(std::io::Cursor::new(bytes))
+                    .filter_map(Result::ok)
+                    .collect();
+
             envs.extend(file_envs.iter().map(|(k, v)| (k.clone(), v.clone())));
             env_vars.extend(file_envs);
         } else {
diff --git a/crates/extension_host/src/wasm_host.rs b/crates/extension_host/src/wasm_host.rs
index a6e5768f16243c..0f92ab60847015 100644
--- a/crates/extension_host/src/wasm_host.rs
+++ b/crates/extension_host/src/wasm_host.rs
@@ -12,6 +12,7 @@ use extension::{
     WorktreeDelegate,
 };
 use fs::{Fs, normalize_path};
+use futures::AsyncReadExt;
 use futures::future::LocalBoxFuture;
 use futures::{
     Future, FutureExt, StreamExt as _,
@@ -763,13 +764,14 @@ impl WasmExtension {
 
         let mut wasm_file = wasm_host
             .fs
-            .open_sync(&path)
+            .open_read(&path)
             .await
             .context(format!("opening wasm file, path: {path:?}"))?;
 
         let mut wasm_bytes = Vec::new();
         wasm_file
             .read_to_end(&mut wasm_bytes)
+            .await
             .context(format!("reading wasm file, path: {path:?}"))?;
 
         wasm_host
diff --git a/crates/fs/src/fs.rs b/crates/fs/src/fs.rs
index 2cbbf61a21e145..24e224820c774d 100644
--- a/crates/fs/src/fs.rs
+++ b/crates/fs/src/fs.rs
@@ -66,6 +66,8 @@ use std::ffi::OsStr;
 #[cfg(any(test, feature = "test-support"))]
 pub use fake_git_repo::{LOAD_HEAD_TEXT_TASK, LOAD_INDEX_TEXT_TASK};
 
+pub type AsyncReadBox = Pin<Box<dyn AsyncRead + Send>>;
+
 pub trait Watcher: Send + Sync {
     fn add(&self, path: &Path) -> Result<()>;
     fn remove(&self, path: &Path) -> Result<()>;
@@ -116,7 +118,7 @@ pub trait Fs: Send + Sync {
         self.remove_file(path, options).await
     }
     async fn open_handle(&self, path: &Path) -> Result<Arc<dyn FileHandle>>;
-    async fn open_sync(&self, path: &Path) -> Result<Box<dyn io::Read + Send + Sync>>;
+    async fn open_read(&self, path: &Path) -> Result<AsyncReadBox>;
     async fn load(&self, path: &Path) -> Result<String> {
         Ok(String::from_utf8(self.load_bytes(path).await?)?)
     }
@@ -732,8 +734,8 @@ impl Fs for RealFs {
         Ok(())
     }
 
-    async fn open_sync(&self, path: &Path) -> Result<Box<dyn io::Read + Send + Sync>> {
-        Ok(Box::new(std::fs::File::open(path)?))
+    async fn open_read(&self, path: &Path) -> Result<AsyncReadBox> {
+        Ok(Box::pin(smol::fs::File::open(path).await?))
     }
 
     async fn open_handle(&self, path: &Path) -> Result<Arc<dyn FileHandle>> {
@@ -2530,9 +2532,9 @@ impl Fs for FakeFs {
         Ok(())
     }
 
-    async fn open_sync(&self, path: &Path) -> Result<Box<dyn io::Read + Send + Sync>> {
+    async fn open_read(&self, path: &Path) -> Result<AsyncReadBox> {
         let bytes = self.load_internal(path).await?;
-        Ok(Box::new(io::Cursor::new(bytes)))
+        Ok(Box::pin(futures::io::Cursor::new(bytes)))
     }
 
     async fn open_handle(&self, path: &Path) -> Result<Arc<dyn FileHandle>> {
diff --git a/crates/project/src/project.rs b/crates/project/src/project.rs
index 5e31f2a90cf137..f0b346747a7334 100644
--- a/crates/project/src/project.rs
+++ b/crates/project/src/project.rs
@@ -4141,7 +4141,11 @@ impl Project {
         searcher.into_handle(query, cx)
     }
 
-    pub fn search(&mut self, query: SearchQuery, cx: &mut Context<Self>) -> Receiver<SearchResult> {
+    pub fn search(
+        &mut self,
+        query: SearchQuery,
+        cx: &mut Context<Self>,
+    ) -> (Receiver<SearchResult>, Task<()>) {
         self.search_impl(query, cx).results(cx)
     }
 
@@ -5025,10 +5029,14 @@ impl Project {
         let path_style = this.read_with(&cx, |this, cx| this.path_style(cx))?;
         let query =
             SearchQuery::from_proto(message.query.context("missing query field")?, path_style)?;
-        let results = this.update(&mut cx, |this, cx| {
+        let (results, search_task) = this.update(&mut cx, |this, cx| {
             this.search_impl(query, cx).matching_buffers(cx)
         })?;
 
+        // Keep the search task alive while we drain the receiver; dropping it cancels the search.
+        // We intentionally do not detach it.
+        let _search_task = search_task;
+
         let mut response = proto::FindSearchCandidatesResponse {
             buffer_ids: Vec::new(),
         };
diff --git a/crates/project/src/project_search.rs b/crates/project/src/project_search.rs
index 90687f24733875..d2671bc4d023d4 100644
--- a/crates/project/src/project_search.rs
+++ b/crates/project/src/project_search.rs
@@ -1,7 +1,6 @@
 use std::{
     cell::LazyCell,
     collections::BTreeSet,
-    io::{BufRead, BufReader},
     ops::Range,
     path::{Path, PathBuf},
     pin::pin,
@@ -11,7 +10,7 @@ use std::{
 use anyhow::Context;
 use collections::HashSet;
 use fs::Fs;
-use futures::{SinkExt, StreamExt, select_biased, stream::FuturesOrdered};
+use futures::{AsyncBufReadExt, SinkExt, StreamExt, select_biased, stream::FuturesOrdered};
 use gpui::{App, AppContext, AsyncApp, Entity, Task};
 use language::{Buffer, BufferSnapshot};
 use parking_lot::Mutex;
@@ -68,13 +67,14 @@ pub struct SearchResultsHandle {
 }
 
 impl SearchResultsHandle {
-    pub fn results(self, cx: &mut App) -> Receiver<SearchResult> {
-        (self.trigger_search)(cx).detach();
-        self.results
+    pub fn results(self, cx: &mut App) -> (Receiver<SearchResult>, Task<()>) {
+        let task = (self.trigger_search)(cx);
+        (self.results, task)
     }
-    pub fn matching_buffers(self, cx: &mut App) -> Receiver<Entity<Buffer>> {
-        (self.trigger_search)(cx).detach();
-        self.matching_buffers
+
+    pub fn matching_buffers(self, cx: &mut App) -> (Receiver<Entity<Buffer>>, Task<()>) {
+        let task = (self.trigger_search)(cx);
+        (self.matching_buffers, task)
     }
 }
 
@@ -683,29 +683,37 @@ impl RequestHandler<'_> {
     async fn handle_find_first_match(&self, mut entry: MatchingEntry) {
         _=maybe!(async move {
             let abs_path = entry.worktree_root.join(entry.path.path.as_std_path());
-            let Some(file) = self.fs.context("Trying to query filesystem in remote project search")?.open_sync(&abs_path).await.log_err() else {
-                return anyhow::Ok(());
-            };
 
-            let mut file = BufReader::new(file);
-            let file_start = file.fill_buf()?;
-
-            if let Err(Some(starting_position)) =
-            std::str::from_utf8(file_start).map_err(|e| e.error_len())
-            {
-                // Before attempting to match the file content, throw away files that have invalid UTF-8 sequences early on;
-                // That way we can still match files in a streaming fashion without having look at "obviously binary" files.
-                log::debug!(
-                    "Invalid UTF-8 sequence in file {abs_path:?} at byte position {starting_position}"
-                );
-                return Ok(());
+            let file = self
+                .fs
+                .context("Trying to query filesystem in remote project search")?
+                .open_read(&abs_path)
+                .await?;
+
+            let mut file = futures::io::BufReader::new(file);
+
+            // Before attempting to match the file content, throw away files that have invalid UTF-8 sequences early on;
+            // That way we can still match files in a streaming fashion without having look at "obviously binary" files.
+            //
+            // Use `fill_buf` so we can "peek" without consuming bytes, and reuse the same stream for detection.
+            let buffer = file.fill_buf().await?;
+            let prefix_len = buffer.len().min(8192);
+
+            if let Err(error) = std::str::from_utf8(&buffer[..prefix_len]) {
+                if let Some(starting_position) = error.error_len() {
+                    log::debug!(
+                        "Invalid UTF-8 sequence in file {abs_path:?} at byte position {starting_position}"
+                    );
+                    return Ok(());
+                }
             }
 
-            if self.query.detect(file).unwrap_or(false) {
+            if self.query.detect(file).await.unwrap_or(false) {
                 // Yes, we should scan the whole file.
                 entry.should_scan_tx.send(entry.path).await?;
             }
-            Ok(())
+
+            anyhow::Ok(())
         }).await;
     }
 
diff --git a/crates/project/src/project_tests.rs b/crates/project/src/project_tests.rs
index 4cebc72073cfda..dc9738738c8f94 100644
--- a/crates/project/src/project_tests.rs
+++ b/crates/project/src/project_tests.rs
@@ -10400,7 +10400,10 @@ async fn search(
     query: SearchQuery,
     cx: &mut gpui::TestAppContext,
 ) -> Result<HashMap<String, Vec<Range<usize>>>> {
-    let search_rx = project.update(cx, |project, cx| project.search(query, cx));
+    let (search_rx, search_task) = project.update(cx, |project, cx| project.search(query, cx));
+    // Keep the search task alive while we drain the receiver; dropping it cancels the search.
+    let _search_task = search_task;
+
     let mut results = HashMap::default();
     while let Ok(search_result) = search_rx.recv().await {
         match search_result {
diff --git a/crates/project/src/search.rs b/crates/project/src/search.rs
index bb37ba2111db45..dffec3f1e417a9 100644
--- a/crates/project/src/search.rs
+++ b/crates/project/src/search.rs
@@ -2,13 +2,13 @@ use aho_corasick::{AhoCorasick, AhoCorasickBuilder};
 use anyhow::Result;
 use client::proto;
 use fancy_regex::{Captures, Regex, RegexBuilder};
+use futures::{AsyncBufRead, AsyncBufReadExt, AsyncReadExt};
 use gpui::Entity;
 use itertools::Itertools as _;
 use language::{Buffer, BufferSnapshot, CharKind};
 use smol::future::yield_now;
 use std::{
     borrow::Cow,
-    io::{BufRead, BufReader, Read},
     ops::Range,
     sync::{Arc, LazyLock},
 };
@@ -326,37 +326,38 @@ impl SearchQuery {
         }
     }
 
-    pub(crate) fn detect(
-        &self,
-        mut reader: BufReader<Box<dyn Read + Send + Sync>>,
-    ) -> Result<bool> {
-        if self.as_str().is_empty() {
+    pub(crate) async fn detect(&self, mut reader: impl AsyncBufRead + Unpin) -> Result<bool> {
+        let query_str = self.as_str();
+        let needle_len = query_str.len();
+        if needle_len == 0 {
             return Ok(false);
         }
 
+        let mut text = String::new();
         match self {
             Self::Text { search, .. } => {
-                let mat = search.stream_find_iter(reader).next();
-                match mat {
-                    Some(Ok(_)) => Ok(true),
-                    Some(Err(err)) => Err(err.into()),
-                    None => Ok(false),
+                if query_str.contains('\n') {
+                    reader.read_to_string(&mut text).await?;
+                    Ok(search.find(&text).is_some())
+                } else {
+                    while reader.read_line(&mut text).await? > 0 {
+                        if search.find(&text).is_some() {
+                            return Ok(true);
+                        }
+                        text.clear();
+                    }
+                    Ok(false)
                 }
             }
             Self::Regex {
                 regex, multiline, ..
             } => {
                 if *multiline {
-                    let mut text = String::new();
-                    if let Err(err) = reader.read_to_string(&mut text) {
-                        Err(err.into())
-                    } else {
-                        Ok(regex.find(&text)?.is_some())
-                    }
+                    reader.read_to_string(&mut text).await?;
+                    Ok(regex.find(&text)?.is_some())
                 } else {
-                    for line in reader.lines() {
-                        let line = line?;
-                        if regex.find(&line)?.is_some() {
+                    while reader.read_line(&mut text).await? > 0 {
+                        if regex.find(&text)?.is_some() {
                             return Ok(true);
                         }
                     }
diff --git a/crates/project/src/worktree_store.rs b/crates/project/src/worktree_store.rs
index 7c3eabd609c5ef..d31193ace16dde 100644
--- a/crates/project/src/worktree_store.rs
+++ b/crates/project/src/worktree_store.rs
@@ -1,5 +1,4 @@
 use std::{
-    io::{BufRead, BufReader},
     path::{Path, PathBuf},
     pin::pin,
     sync::{Arc, atomic::AtomicUsize},
@@ -8,7 +7,7 @@ use std::{
 use anyhow::{Context as _, Result, anyhow, bail};
 use collections::{HashMap, HashSet};
 use fs::{Fs, copy_recursive};
-use futures::{FutureExt, SinkExt, future::Shared};
+use futures::{AsyncBufReadExt as _, FutureExt, SinkExt, future::Shared, io::BufReader};
 use gpui::{
     App, AppContext as _, AsyncApp, Context, Entity, EntityId, EventEmitter, Task, WeakEntity,
 };
@@ -1024,15 +1023,15 @@ impl WorktreeStore {
         let mut input = pin!(input);
         while let Some(mut entry) = input.next().await {
             let abs_path = entry.worktree_root.join(entry.path.path.as_std_path());
-            let Some(file) = fs.open_sync(&abs_path).await.log_err() else {
+            let Some(file) = fs.open_read(&abs_path).await.log_err() else {
                 continue;
             };
 
             let mut file = BufReader::new(file);
-            let file_start = file.fill_buf()?;
+            let file_start = file.fill_buf().await?;
 
             if let Err(Some(starting_position)) =
-                std::str::from_utf8(file_start).map_err(|e| e.error_len())
+                std::str::from_utf8(&file_start).map_err(|e| e.error_len())
             {
                 // Before attempting to match the file content, throw away files that have invalid UTF-8 sequences early on;
                 // That way we can still match files in a streaming fashion without having look at "obviously binary" files.
@@ -1042,7 +1041,7 @@ impl WorktreeStore {
                 continue;
             }
 
-            if query.detect(file).unwrap_or(false) {
+            if query.detect(file).await.unwrap_or(false) {
                 entry.respond.send(entry.path).await?
             }
         }
diff --git a/crates/project_benchmarks/src/main.rs b/crates/project_benchmarks/src/main.rs
index e4ddbb6cf2c7b6..2b42e9e51858ba 100644
--- a/crates/project_benchmarks/src/main.rs
+++ b/crates/project_benchmarks/src/main.rs
@@ -102,9 +102,11 @@ fn main() -> Result<(), anyhow::Error> {
                 println!("Starting a project search");
                 let timer = std::time::Instant::now();
                 let mut first_match = None;
-                let matches = project
+
+                let (matches, _search_task) = project
                     .update(cx, |this, cx| this.search(query, cx))
                     .unwrap();
+
                 let mut matched_files = 0;
                 let mut matched_chunks = 0;
                 while let Ok(match_result) = matches.recv().await {
diff --git a/crates/remote_server/src/headless_project.rs b/crates/remote_server/src/headless_project.rs
index c83cc6aa34402a..4ef18ee99e5961 100644
--- a/crates/remote_server/src/headless_project.rs
+++ b/crates/remote_server/src/headless_project.rs
@@ -771,7 +771,7 @@ impl HeadlessProject {
             message.query.context("missing query field")?,
             PathStyle::local(),
         )?;
-        let results = this.update(&mut cx, |this, cx| {
+        let (results, search_task) = this.update(&mut cx, |this, cx| {
             project::Search::local(
                 this.fs.clone(),
                 this.buffer_store.clone(),
@@ -783,6 +783,10 @@ impl HeadlessProject {
             .matching_buffers(cx)
         })?;
 
+        // Keep the search task alive while we drain the receiver; dropping it cancels the search.
+        // We intentionally do not detach it.
+        let _search_task = search_task;
+
         let mut response = proto::FindSearchCandidatesResponse {
             buffer_ids: Vec::new(),
         };
diff --git a/crates/remote_server/src/remote_editing_tests.rs b/crates/remote_server/src/remote_editing_tests.rs
index a7a870b0513694..35f07696be8466 100644
--- a/crates/remote_server/src/remote_editing_tests.rs
+++ b/crates/remote_server/src/remote_editing_tests.rs
@@ -194,7 +194,7 @@ async fn test_remote_project_search(cx: &mut TestAppContext, server_cx: &mut Tes
     cx.run_until_parked();
 
     async fn do_search(project: &Entity<Project>, mut cx: TestAppContext) -> Entity<Buffer> {
-        let receiver = project.update(&mut cx, |project, cx| {
+        let (receiver, search_task) = project.update(&mut cx, |project, cx| {
             project.search(
                 SearchQuery::text(
                     "project",
@@ -211,6 +211,10 @@ async fn test_remote_project_search(cx: &mut TestAppContext, server_cx: &mut Tes
             )
         });
 
+        // Keep the search task alive while we drain the receiver; dropping it cancels the search.
+        // We intentionally do not detach it.
+        let _search_task = search_task;
+
         let first_response = receiver.recv().await.unwrap();
         let SearchResult::Buffer { buffer, .. } = first_response else {
             panic!("incorrect result");
diff --git a/crates/search/src/project_search.rs b/crates/search/src/project_search.rs
index e0bbf58ce6f1d0..11b6f3323a66fa 100644
--- a/crates/search/src/project_search.rs
+++ b/crates/search/src/project_search.rs
@@ -303,7 +303,7 @@ impl ProjectSearch {
     }
 
     fn search(&mut self, query: SearchQuery, cx: &mut Context<Self>) {
-        let search = self.project.update(cx, |project, cx| {
+        let (search, project_search_task) = self.project.update(cx, |project, cx| {
             project
                 .search_history_mut(SearchInputKind::Query)
                 .add(&mut self.search_history_cursor, query.as_str().to_string());
@@ -326,6 +326,10 @@ impl ProjectSearch {
         self.active_query = Some(query);
         self.match_ranges.clear();
         self.pending_search = Some(cx.spawn(async move |project_search, cx| {
+            // Keep the search task alive for the lifetime of this pending search task.
+            // Dropping it is the cancellation mechanism; we intentionally do not detach it.
+            let _project_search_task = project_search_task;
+
             let mut matches = pin!(search.ready_chunks(1024));
             project_search
                 .update(cx, |project_search, cx| {