Support custom search directories

crates/bridge_core/src/lib.rs

@@ -764,6 +764,11 @@ impl SecuritySettings {
     pub fn allow_shell_escape(&self) -> bool {
         !self.disable_insecures
     }
+
+    /// Query whether we're allowed to specify extra paths to read files from.
+    pub fn allow_extra_search_paths(&self) -> bool {
+        !self.disable_insecures
+    }
 }
 
 impl Default for SecuritySettings {

docs/src/v2cli/compile.md

@@ -18,6 +18,8 @@ tectonic -X compile myfile.tex
 
 #### Usage Synopsis
 
+<!-- Keep options alphabetized -->
+
 ```sh
 tectonic -X compile  # full form
   [--bundle PATH] [-b PATH]
@@ -90,6 +92,8 @@ can trivially defeat this by explicitly clearing the environment variable.
 
 The following are the available flags.
 
+<!-- Keep alphabetized by full name: -->
+
 | Short | Full                      | Explanation                                                                                    |
 |:------|:--------------------------|:-----------------------------------------------------------------------------------------------|
 | `-b`  | `--bundle <PATH>`         | Use this Zip-format bundle file to find resource files instead of the default |
@@ -119,11 +123,13 @@ The following are the available flags.
 The following unstable options may be available. As the name aims to indicate,
 the set of unstable options is subject to change at any time.
 
+<!-- Keep alphabetized: -->
+
 | Expression               | Explanation |
 |:-------------------------|:------------|
 | `-Z help`                | List all unstable options |
 | `-Z continue-on-errors`  | Keep compiling even when severe errors occur |
 | `-Z min-crossrefs=<num>` | Equivalent to bibtex's `-min-crossrefs` flag. Default vaue: 2 |
 | `-Z paper-size=<spec>`   | Change the initial paper size. Default: `letter` |
+| `-Z search-path=<path>`  | Also look in `<path>` for files (unless `--untrusted` has been specified), like TEXINPUTS. Can be specified multiple times. |
 | `-Z shell-escape`        | Enable `\write18` (unless `--untrusted` has been specified) |
-

src/driver.rs

@@ -249,6 +249,9 @@ struct BridgeState {
     /// The main filesystem backing for input files in the project.
     filesystem: FilesystemIo,
 
+    /// Extra paths we search through for files.
+    extra_search_paths: Vec<FilesystemIo>,
+
     /// Additional filesystem backing used if "shell escape" functionality is
     /// activated. If None, we take that to mean that shell-escape is
     /// disallowed. We have to use a persistent filesystem directory for this
@@ -447,6 +450,12 @@ macro_rules! bridgestate_ioprovider_cascade {
             if let Some(ref mut p) = $self.shell_escape_work {
                 bridgestate_ioprovider_try!(p, $($inner)+);
             }
+
+            // Extra search paths. This has higher priority than bundles but lower than current
+            // working dir to support the use case of overriding broken bundles (see issue #816).
+            for fsio in $self.extra_search_paths.iter_mut() {
+                bridgestate_ioprovider_try!(fsio, $($inner)+);
+            }
         }
 
         bridgestate_ioprovider_try!($self.bundle.as_ioprovider_mut(), $($inner)+);
@@ -1060,14 +1069,31 @@ impl ProcessingSessionBuilder {
             None
         };
 
-        let filesystem = FilesystemIo::new(&filesystem_root, false, true, self.hidden_input_paths);
+        // move this out of self to get around borrow checker issues
+        let hidden_input_paths = self.hidden_input_paths;
+
+        let extra_search_paths = if self.security.allow_extra_search_paths() {
+            self.unstables
+                .extra_search_paths
+                .iter()
+                .map(|p| FilesystemIo::new(p, false, false, hidden_input_paths.clone()))
+                .collect()
+        } else {
+            if !self.unstables.extra_search_paths.is_empty() {
+                tt_warning!(status, "Extra search path(s) ignored due to security");
+            }
+            Vec::new()
+        };
+
+        let filesystem = FilesystemIo::new(&filesystem_root, false, true, hidden_input_paths);
 
         let mem = MemoryIo::new(true);
 
         let bs = BridgeState {
             primary_input: pio,
             mem,
             filesystem,
+            extra_search_paths,
             shell_escape_work: None,
             format_cache,
             bundle,

src/unstable_opts.rs

@@ -8,8 +8,12 @@
 //! to be reliable or very polished. In particular, many of these prevent the build from being
 //! reproducible.
 
-use crate::errors::{Error, Result};
+use crate::{
+    errmsg,
+    errors::{Error, Result},
+};
 use std::default::Default;
+use std::path::PathBuf;
 use std::str::FromStr;
 
 const HELPMSG: &str = r#"Available unstable options:
@@ -19,6 +23,8 @@ const HELPMSG: &str = r#"Available unstable options:
     -Z min-crossrefs=<num>      Equivalent to bibtex's -min-crossrefs flag - "include after <num>
                                     crossrefs" [default: 2]
     -Z paper-size=<spec>        Change the default paper size [default: letter]
+    -Z search-path=<path>       Also look in <path> for files, like TEXINPUTS. Can be specified
+                                    multiple times.
     -Z shell-escape             Enable \write18
 "#;
 
@@ -29,6 +35,7 @@ pub enum UnstableArg {
     Help,
     MinCrossrefs(i32),
     PaperSize(String),
+    SearchPath(PathBuf),
     ShellEscapeEnabled,
 }
 
@@ -44,25 +51,30 @@ impl FromStr for UnstableArg {
         // For structopt/clap, if you pass a value to a flag which doesn't accept one, it's
         // silently ignored.
 
+        let require_value = |value_name| {
+            value.ok_or_else(|| {
+                errmsg!(
+                    "'-Z {}=<{}>' requires a value but none was supplied",
+                    arg,
+                    value_name
+                )
+            })
+        };
+
         match arg {
             "help" => Ok(UnstableArg::Help),
 
             "continue-on-errors" => Ok(UnstableArg::ContinueOnErrors),
 
-            "min-crossrefs" => value
-                .ok_or_else(|| {
-                    "'-Z min-crossrefs <spec>' requires a value but none was supplied".into()
-                })
+            "min-crossrefs" => require_value("num")
                 .and_then(|s| {
                     FromStr::from_str(s).map_err(|e| format!("-Z min-crossrefs: {}", e).into())
                 })
                 .map(UnstableArg::MinCrossrefs),
 
-            "paper-size" => value
-                .ok_or_else(|| {
-                    "'-Z paper-size <spec>' requires a value but none was supplied".into()
-                })
-                .map(|s| UnstableArg::PaperSize(s.to_string())),
+            "paper-size" => require_value("spec").map(|s| UnstableArg::PaperSize(s.to_string())),
+
+            "search-path" => require_value("path").map(|s| UnstableArg::SearchPath(s.into())),
 
             "shell-escape" => Ok(UnstableArg::ShellEscapeEnabled),
 
@@ -77,6 +89,7 @@ pub struct UnstableOptions {
     pub paper_size: Option<String>,
     pub shell_escape: bool,
     pub min_crossrefs: Option<i32>,
+    pub extra_search_paths: Vec<PathBuf>,
 }
 
 impl UnstableOptions {
@@ -97,6 +110,7 @@ impl UnstableOptions {
                 MinCrossrefs(num) => opts.min_crossrefs = Some(num),
                 PaperSize(size) => opts.paper_size = Some(size),
                 ShellEscapeEnabled => opts.shell_escape = true,
+                SearchPath(p) => opts.extra_search_paths.push(p),
             }
         }
 

tests/executable.rs

@@ -794,3 +794,41 @@ fn shell_escape_env_override() {
 
     error_or_panic(&output);
 }
+
+/// Test that include paths work
+#[test]
+fn extra_search_paths() {
+    let fmt_arg = get_plain_format_arg();
+    let tempdir = setup_and_copy_files(&["subdirectory/content/1.tex"]);
+
+    let output = run_tectonic_with_stdin(
+        tempdir.path(),
+        &[&fmt_arg, "-", "-Zsearch-path=subdirectory/content"],
+        "\\input 1.tex\n\\bye",
+    );
+    success_or_panic(&output);
+
+    let output = run_tectonic_with_stdin(
+        tempdir.path(),
+        &[
+            &fmt_arg,
+            "-",
+            "--hide=subdirectory/content/1.tex",
+            "-Zsearch-path=subdirectory/content",
+        ],
+        "\\input 1.tex\n\\bye",
+    );
+    error_or_panic(&output);
+
+    let output = run_tectonic_with_stdin(
+        tempdir.path(),
+        &[
+            &fmt_arg,
+            "-",
+            "-Zsearch-path=subdirectory/content",
+            "--untrusted",
+        ],
+        "\\input 1.tex\n\\bye",
+    );
+    error_or_panic(&output);
+}