demos: automate running demos and update them

demos/README.md

@@ -0,0 +1,44 @@
+# Screenshots with demos and scripts to generate them
+
+The `demo_*.sh` scripts in this directory demo
+various features of `jj`.
+
+The `run_scripts.sh` script can be used to:
+
+- Run them inside a standardized environment instead of the user's local
+  environment.
+- Generate SVG and PNG images for the scripts.
+
+The PNG images in the repo may be slightly older, as they take up more space in
+the repo.
+
+The SVG images have human-readable diffs, but may look different on different
+computers with different fonts installed.
+
+## Running `run_scripts.sh`
+
+This requires ImageMagick and `term-transcript-cli` to be installed. See
+`run_scripts.sh`'s error messages for some more details. On Debian Linux, it
+also seems helpful to `sudo apt install inkscape`; ImageMagick seems to use
+either Inkscape itself or some dependency of it.
+
+One way to make all the images and check the output is:
+
+```shell
+cd demos
+./run_scripts.sh demo_*.sh |less
+```
+
+### A note on fonts
+
+The exact PNG output depends on the fonts you have installed on your system.
+
+The screenshots are usually generated on a Debian Linux system and use the "Fira
+Code" font. It can be installed with `sudo apt install fonts-firacode`. It seems
+to include all relevant Unicode symbols and be a little bolder and thus more
+readable than the "Liberation Mono" font, which is used if Fira Code is not
+installed. That font also works OK. See the CSS font specification in
+`run_scripts.sh` for other fonts tried (especially when viewing SVGs on the
+web). If none apply, the default `monospace` font will be used.
+
+`convert -list Fonts` will list the fonts ImageMagick is aware of.

demos/demo_git_compat.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 set -euo pipefail
-. "$(dirname "$0")"/demo_helpers.sh
+. "$(dirname "$0")"/helpers.sh
 
 new_tmp_dir
 
@@ -10,6 +10,7 @@ run_command "cd Hello-World"
 
 comment "Inspect it:"
 run_command "jj log -r 'all()'"
+blank
 run_command "jj diff -r b1"
 
 comment "The repo is backed by the actual Git repo:"

demos/demo_juggle_conflicts.sh

@@ -1,18 +1,20 @@
 #!/bin/bash
 set -euo pipefail
-. "$(dirname "$0")"/demo_helpers.sh
+. "$(dirname "$0")"/helpers.sh
 
 new_tmp_dir
-jj init --config-toml ui.allow-init-native=true
-echo "first" > file
-jj branch create first
-jj commit -m 'first' 
-echo "second" > file
-jj branch create second
-jj commit -m 'second' 
-echo "third" > file
-jj branch create third
-jj commit -m 'third' 
+(
+    jj init --config-toml ui.allow-init-native=true
+    echo "first" > file
+    jj branch create first
+    jj commit -m 'first'
+    echo "second" > file
+    jj branch create second
+    jj commit -m 'second'
+    echo "third" > file
+    jj branch create third
+    jj commit -m 'third'
+) >/dev/null
 
 comment "We are in a repo with three commits, all
 editing the same line:"
@@ -26,13 +28,11 @@ comment "Let's reorder the second and third commits:"
 run_command "jj rebase -s third -d first"
 run_command "jj rebase -s second -d third"
 run_command "jj log"
-comment "The commit labeled \"third\" has a conflict,
-as expected. What's more interesting is
-that the top commit has no conflict! That's
-because it has the changes from all three
-commits applied to it."
+comment "The commit labeled \"third\" has a conflict, as expected. What's more
+interesting is that the top commit has no conflict! That's because it
+has the changes from all three commits applied to it.
 
-comment "Let's verify that by looking at its contents:"
+Let's verify that by looking at its contents:"
 run_command "jj co second"
 run_command "cat file"
 

demos/demo_operation_log.sh

@@ -1,10 +1,14 @@
 #!/bin/bash
 set -euo pipefail
-. "$(dirname "$0")"/demo_helpers.sh
+. "$(dirname "$0")"/helpers.sh
 
 new_tmp_dir
-jj git clone https://github.com/octocat/Hello-World
-cd Hello-World
+{
+    jj git clone https://github.com/octocat/Hello-World
+    cd Hello-World
+    jj abandon octocat-patch-1
+    jj branch forget octocat-patch-1
+} > /dev/null
 
 comment "We are in the octocat/Hello-World repo.
 The \"operation log\" shows the operations
@@ -27,10 +31,10 @@ comment "The repo now looks like this:"
 run_command "jj log"
 comment "The most recent portion of the operation log
 is:"
-run_command "jj op log --color=always | head"
+run_command_allow_broken_pipe "jj op log --limit 4"
 
 comment "Let's undo that rebase operation:"
-rebase_op=$(jj --color=never op log | grep '^◉  ' | sed '2q;d' | cut -b4-15)
+rebase_op=$(jj --color=never op log --no-graph -T 'id.short(5)' --limit 1 --at-op @--)
 run_command "jj undo $rebase_op"
 
 comment "Note that only the rebase was undone, and the

demos/demo_resolve_conflict.sh → demos/demo_resolve_conflicts.sh

@@ -1,36 +1,43 @@
 #!/bin/bash
 set -euo pipefail
-. "$(dirname "$0")"/demo_helpers.sh
+. "$(dirname "$0")"/helpers.sh
 
 new_tmp_dir
-jj git clone https://github.com/octocat/Hello-World
-cd Hello-World
+{
+    jj git clone https://github.com/octocat/Hello-World 
+    cd Hello-World
+    jj abandon test
+    jj branch forget test
+} > /dev/null
 
 comment "We are on the master branch of the
 octocat/Hello-World repo:"
-run_command "jj log -r 'all()'"
+run_command "jj log"
 
 comment "Let's make an edit that will conflict
 when we rebase it:"
 run_command "jj describe -m \"README: say which world\""
 run_command "echo \"Hello Earth!\" > README"
 run_command "jj diff"
 
+# TODO(ilyagr): Get the real shortest prefix of the b1b commit using `jj log
+# --no-graph` and the `.shortest()` template function.
+#
+# This could also be done in demo_git_compat.sh, but that might not be worth it.
 comment "We're going to rebase it onto commit b1.
 That commit looks like this:"
 run_command "jj diff -r b1"
 
 comment "Now rebase:"
 run_command "jj rebase -d b1"
 
-comment "Huh, that seemed to succeed. Let's take a
-look at the repo:"
-run_command "jj log -r 'all()'"
+comment "That seemed to succeed but we are also told there is now a conflict.
+Let's take a look at the repo:"
+run_command "jj log"
 run_command "jj status"
 
-comment "As you can see, the rebased commit has a
-conflict. The file in the working copy looks
-like this:"
+comment "Indeed, the rebased commit has a conflict. The conflicted file
+in the working copy looks like this:"
 run_command "cat README"
 
 comment "Now we will resolve the conflict:"

demos/demo_working_copy.sh

@@ -1,24 +1,29 @@
 #!/bin/bash
 set -euo pipefail
-. "$(dirname "$0")"/demo_helpers.sh
+. "$(dirname "$0")"/helpers.sh
 
 new_tmp_dir
-jj git clone https://github.com/octocat/Hello-World
-cd Hello-World
+{
+    jj git clone https://github.com/octocat/Hello-World
+    cd Hello-World
+    jj abandon test
+    jj branch forget test
+    jj abandon octocat-patch-1
+    jj branch forget octocat-patch-1
+}> /dev/null
 
 comment "We are in the octocat/Hello-World repo.
 We have an empty working copy on top of master:"
-run_command "jj status"
 run_command "jj log"
+run_command "jj status"
 
 comment "Now make some changes in the working copy:"
 run_command "echo \"Goodbye World!\" > README"
 run_command "echo stuff > new-file"
 
-comment "Our working copy's commit ID changed
-because we made changes:"
+comment "Because of these changes, our working copy is no longer marked as \"(empty)\".
+Also, its commit ID (starting with a blue character) changed:"
 run_command "jj status"
-run_command "jj log"
 
 comment "Add a branch so we can easily refer to this
 commit:"
@@ -27,24 +32,27 @@ run_command "jj log"
 
 comment "Start working on a new change off of master:"
 run_command "jj co master"
-run_command "jj log"
-
-comment "Note that the working copy is now clean; the
+comment "Note that we were told the working copy is now empty (AKA clean). The
 \"goodbye\" change stayed in its own commit:"
+
+run_command "jj log"
+comment "Let's do a sanity check: 'jj status' should tell us that
+the working copy is clean."
 run_command "jj status"
 
 comment "Modify a file in this new change:"
 run_command "echo \"Hello everyone!\" > README"
+run_command "jj status"
 
 comment "The working copy is not special; we can, for
 example, set the description of any commit.
 First, set it on the working copy:"
-run_command "jj describe -m everyone"
+# The output with the description of the working copy slightly messes up the
+# parallel between the working copy and another commit, so we redact it.
+run_command_output_redacted "jj describe -m everyone"
 
 comment "Now set it on the change we worked on before:"
 run_command "jj describe goodbye -m goodbye"
 
 comment "Inspect the result:"
 run_command "jj log"
-
-blank